Hi ALl,

At present this is just a hypothetical discussion for me - as have just taken receipt of my PD diesel (so has a DPF fitted) and it had a dealer service just a few months ago using the 'Hyundai recommended' 5w-30 C3 oil.

My query is this - why given Australia's high temps (and could be anywhere in the world as temps often just as high in Europe etc) is 5w-30 oil used?  Going by the i30 manual - for the U2 1.6 TCI diesel engine the recommended oils and temp ranges (all degrees C) are:

OIL WEIGHT                TEMP RANGE
15w-40                            -15 to 50
10w-30                           -20 to 40
5w-30                             -25 to 40
0w-30                            -30 to 30

So to me using 5w-30 that is not recommended over 40 degrees seems stupid given the average Aussie summer might have a dozen+ days of those - not to mention actual on road temps in high traffic being well above this.

Further making using such light oils a concern is the affect that fuel dilution back into the oil can have - apparently it happens in all cars and certain models are more prone to it - but there are articles saying its far more common than people think and can occur within a few months.  So your 5w-30 oil can easily be reduced to 5w-20 - which then leads to shearing where it's too thin to protect metal on metal rubbing etc. See this thread to see what a guy who had a Ford TDI found when he checked his oil via a UOA (used oil analysis?) -fuel dilution in diesels

We can assume the same thing occurs in Hyundai's perhaps not that badly but it's still reducing whats already a thin oil down - especially when the oil change intervals are 15,000kms - which is 2-3x the intervals that guy did.

FWIW has anyone running a late model Hyundai diesel done an UOA?  There are a few labs here in Oz that do them - curious what your results were.

Anyway - so factoring that ON TOP of the already questionable temp ranges I do wonder why Hyundai Oz continues to insist on 5w-30 being used and if common sense would say that a heavier grade of oil should be used not only to help in higher running temps - but so over such a long oil change period WHEN fuel dilution that occurs (as it's a certainty, not an IF) the oil doesn't drop to viscosity thats unacceptably low.

Oh and let me just say the whole 'lower fuel consumption on lighter viscosity oils is apparently a bit of a furfy - a pretty ordinary 15w-40 oil only used UP TO 1% more fuel than a 5W-30 - so given that you may be exposing your engine to much higher wear via higher temp range and viscosity thats dropped completely out of range (via fuel dilution) it's clearly a false economy many times over.  Fuel consumption study

Thoughts?

Like I said is just a 'reading up and this occurred to me' thing - so wanted to run by the much more learned folk here - so poke holes in it all you like, just trying to get to the bottom of things.

Also on a side note....for DPF equipped i30's the manual recommends ACEA C2 or C3 rated oils be used.  Dealers seem to put in C3 rated oil.  Has anyone looked into the viability of using the supposably 'higher' rated C4 oil?   Curiously this is cheaper at SCA than the 'lower' C3 rated stuff.

Thanks, Nick

     

[Dazzler]

Hi Nikko, Me again. The site was getting a bit quiet a month or two ago  but you and a few other members have livened things up again.  Thanks for that!
I know the UK doesn't get as hot, but them and some other places have 30K service intervals on the diesel! 

I think there is a 15 W40 oil you can use in the PD diesel isn't there. If you are stressed by this issue (with good reason from the look of your research, why not get an oil change only done with 15 W40 at say the end of October before the summer hits and then supply this grade for all future services.

It's obviously far less of an issue in Tassie but I supply my own Penrite approved oils for all our Hyundai vehicles.  I believe it is better oil than the bulk stuff the dealer probably uses and they take more off the bill than it costs me on special.

Hi Nikko, Me again. The site was getting a bit quiet a month or two ago  but you and a few other members have livened things up again.  Thanks for that!

Ah well happy to assist but I am sure there's a lot of lurkers and great members that just didn't have the PITA key issues etc I've been 'blessed' with.

I know the UK doesn't get as hot, but them and some other places have 30K service intervals on the diesel! 

30k?  That seems crazily high - I really would be fascinated to know if anyone has gotten an oil test done on their i30 when it's getting close to 15k on it's oil - it would be very interesting to know to what level fuel dilution is affecting them - it's certain to be a factor, just how much of one.

I think there is a 15 W40 oil you can use in the PD diesel isn't there. If you are stressed by this issue (with good reason from the look of your research, why not get an oil change only done with 15 W40 at say the end of October before the summer hits and then supply this grade for all future services.

Oh I wouldn't say 'stressed' if it read that way it's definitely not the case at all - as I tried to state it was more that I was hoping someone could clarify WHY Hyundai Oz gives 5W-30 oil when this seems ill suited for our climate - something that would be made even worse by whatever the level of fuel dilution to it is.

I in no way pretend to be an expert in these areas hence hoping someone could point out what I was missing as it seemed a odd and illogical choice.

I am unsure if there's a 15W-40, I've not looked into it much yet - am sure there'd be something - I know Penrite does a 5W-40 and a 10W-40 (that it oddly states is 'Suitable for use' in C3 specified cars - it's odd as the oil isn't c3 rated but they say that instead.

It's obviously far less of an issue in Tassie but I supply my own Penrite approved oils for all our Hyundai vehicles.

I dunno you guys get a few hot ones - plus honestly if those are the limits, why would you even want to push the line in 5W-30 oil, I mean most folks are not using the -25c range - but moving the high end temp range up would seem 'handy'.  Perhaps an oil boffin will have a rationale but I'm not seeing it.

I am glad you mentioned that the dealers will allow you to supply your own oils - I suspected that either they'd get the craps or do the old fake/no discount i.e use their oil it's $350, supplying your own oil it's  $330 as they just mark up other bits to ensure they make up the 'lost' profit margin item.

So yeah, not stressed at all - just curious as while it seems 5W-30 might be ok for most of Europe - seems 5W-40 is much better choice for us (going the 15W-40 doesn't seem any more helpful for the high temp protection).

FWIW I actually stumbled over what might be the answer to my query as to whether you can use C4 oils in C3 rated cars (the PD is C2/C3, the latter being what they put in at services).  Penrite's site states:

ACEA C grade oils are for the most, not interchangeable with one another depending on the particular applications. e.g. An ACEA C4 engine oil, cannot be used where an ACEA C3 oil is specified by the manufacturer as the C4 has a lower Sulphated Ash requirement than a C3 oil. This could lead to longevity issues with the engine. Alternatively, if a C3 oil is used in place of a C4 oil, this could cause issues with after treatment systems such as DPFs or catalysts in the exhaust system.

Seems straight forward right - the curious thing being I looked into how lower sulphated ash issues might actually be a negative in engines - as if anything it seems a positive i.e less sulphated ash in a DPF equipped car is good!  Couldn't find anything at all stating why, the only thing is maybe higher sulphated ash helps protect against internal corrosion but that seems unlikely as the rationale and apparently the TBN (total base number) is more indicative of an oils ability to do this - and for Penrite the C4 and C3 oils are rated identical for this.

To further muddy the water again in another area when listing the benefits of it's C4 oil Penrite states this:

Suitable for ACEA C4 and C3 applications

????  So in one area they say don't use C4 in C3 but then for it's C4 it says it's ok for use in C3......completely contradictory.

Anywho I've emailed Penrite to ask them to clarify - I also asked them their thoughts on the whole Hyundai saying 5w-30 but Aussie temps seemingly better for a 40 oil - interested to hear what they say and will share.

I know it all seems pedantic BUT it doesn't get more central to any car's health than engine oil (perhaps quality fuel only surpasses) and so if we're using stuff thats not really suited just because some person in Seoul says so - thats a worry.

[Purplehazeffc]

This is an American Hyundai Service Bulletin dated 28th November 2016. In regards to what oil grade should be used.
It pretty much mentions exactly what you are saying. In that different area's are hotter in summer than others.  So in hotter area's 5w-40 is better to use.

When I first saw this I messaged Hyundai Australia via Facebook Message. And the reply I got back was that this Bulletin DOES-NOT include Australia. And that 5w-30 is still the correct oil to use.   
I change my oil every 5000k's With the dealer doing it at each 10,000k's when the service is due.
So hopefully that should keep the fuel dilution down.  Which specially direct injected petrol & diesels are know for

If you would like some more info on oils. This web site is really good. It is in Russian. But it can be translated into English using Google Chrome.
????? oil-club.ru - ????? ???????? ?????, ??????????????? ?????????, ??????????, ???????, ??????. ????? ????????? ? ?????????????.

[CraigB]

If worried about pushing the heat barrier limit grab the 5W-40, I’d still stick with a 5W for quick circulation at startup 

This is an American Hyundai Service Bulletin dated 28th November 2016. In regards to what oil grade should be used.
It pretty much mentions exactly what you are saying. In that different area's are hotter in summer than others.  So in hotter area's 5w-40 is better to use.

When I first saw this I messaged Hyundai Australia via Facebook Message. And the reply I got back was that this Bulletin DOES-NOT include Australia. And that 5w-30 is still the correct oil to use. 

Excellent find....haha and it's nice to know I wasn't astray with the logic.

I can't believe Hyundai Australia advised that - did they provide a rationale as to why that logic would apply in USA but not here?  I mean that makes absolutely no sense whatsoever as if they've acknowledged higher temps anywhere mean they should be using higher temp oil then it stands to reason that it's something they should do everywhere.  It's not like there's some variable that would mean thats not valid here.

The only thing I can imagine is that maybe they were facing legal action in the USA - and so did that to avoid it - but thats not an issue here.

I am sorry but I'm calling complete BS on them for that and I'd be fascinated to see what they'd say if they were emailed and essentially asked to explain why that makes sense in the USA but not here.

If worried about pushing the heat barrier limit grab the 5W-40, I’d still stick with a 5W for quick circulation at startup

Well I already thought the 40 made sense on amateur logic alone - now Hyundai USA's policy change seems to confirm that makes sense - so that Hyundai Australia issued a 'just do as we say' without any explanation (that I'm aware of yet - though I'd be fascinated) I think it's definitely the 'smart' option to go with the higher temp rated oil.

i mean really other than its in the manual - why would you chose the 5w-30 over it?  Does it get over 40c here much?  Certainly does and we all know how much hotter it is standing on asphalt - so thats a no brainer IMHO.....and as stated and confirmed by purplehazeffc fuel dilution is a well known fact for direct injected engines - so by the time you're 1/2 way through your oil's life it's likely waaaaaaaaaaaaaaaay under being a 30 oil and is much, much thinner - that is not good.

Yes, you're right in that sticking with the 5w is better - if only as it's basically much more widely available than 15w - especially in the C2/3 rated stuff.

[CraigB]

  I’d personally use the 5W-40 in a diesel too, they seem to be affected by ambient temps more than petrol models, it does mention you can use a C4 oil for your model which is supposed to make the DPF last longer...Hyundai likely don’t use it because of costs.

Mine (petrol) for instance I use Penrite 5W-30 PAO oil which is sheer free and easily handles 50c temps

[Purplehazeffc]

I didn't go into much more detail or question with Hyundai when they said to keep using the 5w-30.
As I said, I change mine every 5000k's anyway. So that should help out with the oil dilution.
Plus 75% of my driving is freeway stuff. So the oil temp should stay fairly consistent. And longer running times helps with burning off that fuel in the oil.

Stop / start or short trips would make it a fair bit worse. Then I would more than like lean on using 5w-40. Or even if you do any sort of track type driving.

Apart from slightly higher fuel consumption.   There is probably no reason to not be using the 5w-40

I’d personally use the 5W-40 in a diesel too

Well it seems we all agree on that - well other than Hyundai Australia - I might have to email them and pose a please explain.

it does mention you can use a C4 oil for your model which is supposed to make the DPF last longer

Where did you see that?  As the manual says no C4 in this model - Penrite flops back and forth on it - if you use their model selector tool (which even they concede is kinda flawed) it says C4 isn't suitable and says to use C3.....but then with it's C4 it says it can be used in C3.....hahaha but then again in another area it says don't use C4 in C3 cars!!!!   No wonder folks just use C3 and be done with it.

Hyundai likely don’t use it because of costs.

Well who knows what logic they're using - though the bottomline seems a logical one to still apply - but as stated oddly enough at SCA's normal prices Penrite's C4 is actually less than their same product in C3 ($12 cheaper in 10L size) - so if anything I'd say the prices are likely the same so you'd thikn if it was superior, as it seems the C4 is especially for DPF cars, why not use it?

[mickd]

Now I'm going to throw the cat amongst the pigeons 
What temp does your engine run at when at normal temp ?
Most will be greater than 90 degrees,  some up to 110 degrees.




So: the most common factor is -start up temp as said by Craigb.
Ensure good flow AND pressure when COLD. 

I didn't go into much more detail or question with Hyundai when they said to keep using the 5w-30.

Fair enough I might shoot off an email to them - if nothing else it will shit them and I'm curious to see how they explain it.

Apart from slightly higher fuel consumption.   There is probably no reason to not be using the 5w-40

Well to be fair as that study I linked showed the fuel consumption difference between the 30 and 40 is AT MOST 1% - so thats really in anyone's definition (unless you're doing an astounding number of kms each yr - exactly the same - $20 saved on $2000 worth of fuel isn't really a saving worth noting as at that point tyre pressure would get you many fold more savings.  Not being argumentative but just saying it's kind of a moot point in that regard whereas the higher protection of the 40 in a normal Ausatralian year of driving is kinda undeniable....hence very odd Hyundai deny this being correct - as the USA did.

Now I'm going to throw the cat amongst the pigeons 
What temp does your engine run at when at normal temp ?
Most will be greater than 90 degrees,  some up to 110 degrees.

Sorry but I'm missing your point.  I'm just going by the Hyundai oil recommendations in their manual so what temp an engine runs at is not a variable I'm really sure comes into play in so much as that changes anything stated.

So: the most common factor is -start up temp as said by Craigb.
Ensure good flow AND pressure when COLD. 

Sorry but most common factor in what?  Start up viscosity of oil is one thing and no-one has questioned that - hence why I said sticking with one that has a 5w rating for that makes sense (though I am sure you could go with a 10w or 15w and at our normal startup temps, lets assume 24c - I would imagine the viscosity of 5/10/15 would be pretty identical at that )- though I'm sure you could find data on comparing those weights at normal starting temps - as that would be interesting to see if the lighter ones really have much of an advantage or is it just smoke and mirrors.

But again I've not questioned start up temps (other than in Australia as a general rule we never have such low temps) whereas in Europe and other parts of world it's not unknown to change your oil for summer and winter as you need very different ones.

I'd like to think we're on the same page here - so lets not pop 'friendly fire' on each other - the plain cold facts (and please tell me if I'm wrong) are:
- Hyundai Aust puts and recommends 5w-30 in these cars
- Hyundai Aust do not recommend using this oil outside of 40c ambient temps
- Hyundai USA advise different on this saying use 5w-40
- Australia is more and more having a lot of days above 40c and certainly countless ones in the very high 30's, so pushing the envelope of that limit
- Fuel dilution is a real issue for direct injection cars, so a 30 oil can easily be a 20 only a few months into its change interval - which makes any issues much, much worse.

Add that all together and it seems odd to me.

[CraigB]

Unless you are really pushing it or towing you'll probably find the 5W-30 will still cover you anyway, piece of mind I suppose if your able to find a 5W-40.

Fuel dilution I wouldn't be so concerned with as many countries have 20 or 30 thou services without being affected, plus modern engines have much tighter clearances and within our 5k to 15k servicing it's not really an issue in Australia.

Unless you are really pushing it or towing you'll probably find the 5W-30 will still cover you anyway, piece of mind I suppose if your able to find a 5W-40.

To be fair and please get me straight here - I mean zero offence - but on what basis - given those facts I stated in previous post (or so) - would you say the 5w-30 would be fine? And if so why, specifically?   As on face value alone I'd put it to you that the 30 offers no advantage over the 40 at all - but yet there's a lot of reasons to go the other way. Again don't get me wrong here I'm not trying to be a nelly or argumentative but it seems that using 5w-30 is pretty daft given whats known and even conceded by Hyundai i.e temp ranges and USA's policy change.

Fuel dilution I wouldn't be so concerned with as many countries have 20 or 30 thou services without being affected, plus modern engines have much tighter clearances and within our 5k to 15k servicing it's not really an issue in Australia

.
Hmmm well I'm not saying you're wrong - far from it but just curious has anyone on here done a UOA?  As really thats the only way to know - and there's plenty of modern engines that do have such issues as shown via my link in OP (Mk3 Ford TDCi 2015 engine). So again not being a nelly - but its a very gray area - moreso as there's already a very questionably thin oil at normal operating temps being used and recommended - so unless it can be ruled out it'd be unfair to just say 'I'm sure it's fine."

Haha again and as I'm new I'm going to emphasise this - I am not trying to shit stir people or make a mountain out of a molehill - but this seemed an irrational recommendation by Hyundai Australia at face value - the more I dug the worse it seemed - and now it seems like another one of those times where Australia get 2nd class info/service compared to how multinationals do things overseas.  I was just hoping people could point out to me - "Oh but you're missing A, B and C - thats why what Hyundai said makes sense." that actually would have been my preferred option - but I'm yet to see even close to a decent reason why 5w-30 would be recommended by them over the 40 version.

[CraigB]

I didn't say 30 would be an advantage over 40, just that 30 will still be fine otherwise Hyundai would have a lot of warranty repairs on engines if they didn't deem it safe to use, as mentioned 40 would be piece of mind.

I've never had a UOA performed for specifics but as never personally having an issue with oil dilution it's never been a concern for myself changing oil every 7500km's.

I didn't say 30 would be an advantage over 40, just that 30 will still be fine otherwise Hyundai would have a lot of warranty repairs on engines if they didn't deem it safe to use, as mentioned 40 would be piece of mind.

But to be fair thats basically a 'she'll be right mate' - and those facts given (and again happy to be pulled up on them) would all indicate good reasons why 30 wouldn't be 'fine'.

The only thing really that could be argued is whether 'not fine' is still perfectly acceptable i.e you could run 5w-30 and do marginally more damage to engine than 5w-40 for lifespan of car and never notice the difference.  And I'd imagine thats a question well above both our paygrades. :-) 

just that 30 will still be fine otherwise Hyundai would have a lot of warranty repairs on engines if they didn't deem it safe to use, as mentioned 40 would be piece of mind.

Again I'd have to disagree with you here - as stated above the marginal damage caused might either be at best trivial and impossible to actually manifest itself in tangible ways - which would be ideal for all.  Or if it did show up in numbers of issues, then it still actually has to be provable that Hyundai recommending the wrong oil was the cause - and again thats something that the average Joe is going to have a bloody hard time doing.

So on the contrary now - if Hyundai Australia did make like their USA brethren then they'd ACTUALLY be opening themselves up to potential issues as they'd be acknowledging that they gave incorrect advice for many yrs....THAT would make them far more liable to issues being brought and actually being provable.

So what do most big companies do in situations like this?  They stick with the company line i.e smoking doesn't cause cancer, teflon is safe to consume, asbestos is not the cause of lung issues etc - ok thats being dramatic but you get what I'm saying, that they don't change what they're saying is in no way a reflection of that advice being either good or correct.

And not to get semantic on you - but to do something for peace of mind is more where one does something as overkill, unnecessary etc but it's just so they can know they over did it just to be safe. But using 5w-40 isn't that as I'm going to go as far as saying the average Australian driver would be a tad silly to allow 5w-30 to be used as there's no good basis for this in infact 5w-40 is without doubt the superior weighting to use.

I've never had a UOA performed for specifics but as never personally having an issue with oil dilution it's never been a concern for myself changing oil every 7500km's.

No, I'd expect not - as I think it's a pretty rare thing - I only had one done once and that was as a company was doing them for free - though at the time I had basically no idea what the real benefit.rationale for them was.

Hmmmm well look having read a few more things now all I can say in isolation fuel dilution isn't a big issue - but when you add it to the fact that it seems inappropriately thin oil is being recommended by the maker - and that most drivers likely do exactly the type of driving that leads to more fuel dilution e.g short trips, lots of idling - and tack onto this service intervals are longer than ever and the new engine tech in use (CRD and GDI is more prone to it) - I think for the average Joe, it's a factor - they just don't know about it.

Really changing your oil more regularly or using higher weight oil is the only defence.  I mean I just watched a John Cadogan video on it - and look while he has some good info he does carry on like a real twit a tad much and also often be a jerk when it's not needed.  His explanation of how people should keep a look out for it also was pretty dumb - in that he said to check your dipstick and see if the level has risen.

While that'd protect against the level getting so high it killed the engine (which I believe Mazda had issues with) they regard problematic dilution levels as being IIRC 3.5% in diesels and 2.x% in petrol - now if a person can detect that % change on a dipstick I'll eat my shoe.  Apparently it only takes getting to those levels and the oil effectively drops down to approx the weight below it so 30 to 20, 40 to 30 etc.  So is a big deal IF it's happening - anyway seems neither of us are aware of how i30's fare with this - but I was just flagging as it's an unknown but needs to be considered.

Haha and again sorry if any of this comes across badly etc - I don't mean to be that way, I am just a bit Aspy and well often I can be dogmatic with a subject - thats not to say I'd not be very happy to be proven wrong on any or all things as I've currently got no 'skin in the game' as they say.

[CraigB]

However you want to put the spin on it...if you want to use the 40 then do it, it's still piece of mind no matter what

You'll also notice that if your dealer is using 5W-30, Hyundai in the next suburb could be using 5W-40 as I see here often, Rockingham Hyundai (AHG) used to use Castrol Magnetec 5W-40 A3B4 for all vehicles then later changed to Castrol edge 5W-30 A3B4 when suggested in my manual I should be using A5 spec oil, Hyundai Maddington (DVG) are using Shell Ultra 5W-40 A3B4 which I used myself for some time until switching to Penrite 5W-30 A5 PAO...for my own piece of mind

However you want to put the spin on it...if you want to use the 40 then do it, it's still piece of mind no matter what

Hmm well I'd say we agree the 40 should be used - you say that'd be for peace of mind, I say it's for common sense. The end justifies the means perhaps.

You'll also notice that if your dealer is using 5W-30, Hyundai in the next suburb could be using 5W-40 as I see here often, Rockingham Hyundai (AHG) used to use Castrol Magnetec 5W-40 A3B4 for all vehicles then later changed to Castrol edge 5W-30 A3B4 when suggested in my manual I should be using A5 spec oil, Hyundai Maddington (DVG) are using Shell Ultra 5W-40 A3B4 which I used myself for some time until switching to Penrite 5W-30 A5 PAO

Yeah well first of all 'could be' doesn't exactly inspire confidence - you'd expect there was a standard and that would be followed - hardly asking much. So you know dealers are autonomously putting 5w-40 in diesels without prompting?   Sure it's not the owners asking for this?

Is confusing as you start referencing petrol oil in same sentence - and obviously very different (though I'm not sure of specs for petrol oil so I'll defer to you on this).

Again though you've shown that the dealers are hardly to be either trusted or relied upon for either common sense or integrity as it seems they were putting oil in your car that wasn't meeting the specs of Hyundai and they'd have known this.

for my own piece of mind

Now now, another peace of mind quip and I might have to consider giving you a piece of my mind.  ;-) Obviously kidding....but seriously dodgy and questionable effort by Hyundai on a very basic issue - love to know why whats good for the Goose (USA) isn't for the Gander (lil ole us).

[CraigB]

In the end it comes down to what they deem suitable at a cost, this is why they allow you to choose your own oils as one persons use - needs -driving style - demographic region might require different or more advanced spec, it should be noted that not just Hyundai but all car brands and dealerships do this with their oil used and it's consumers preference of choice to either stick with what they provide or go above recommended.

All those oil's I mentioned other than the A5 were also suitable for light diesels, as I mentioned earlier Hyundai were using those oils across their fleet, cheapest to supply one oil that suits all.

[mickd]

Hi Nikko,
Been making & eating pizzas, yum.
Oil is a funny subject. Yes different weights and viscosity stated for temps.
0, 5, 10 w oil are available.  Mineral,  semi and full synth oil as well.
Maybe the oil industry marketing is confusing us all, even manufacturers.
Change it often is the key, if it looks crap, dump it.
 I had a 1998 diesel hilux 2wd ute  work provided,  oil change every 5000km. I  was working between Sydney,  QLD border and Mudgee, clocking up 4800 to 5200 every 2 weeks   
Mech loved it, oil & filter every 2 weeks for 6 months 
Luckily manual only states "oil for temps".
My bikes use 1990's tech.
 4cyl, oil & air cooled, 1127cc, dohc, 4 valve per cyl, 10,000 redline, 5,000 is 120 kph, same oil for gearbox and shaftdrive pinion and wet clutch. 0 to 240 in12 s.
States similar oils for  air temps. Air /oil cooler doesn't open till 90 deg, oil expected to reach 120 deg. Manual goes on to state,  oil pressure must be between 300 and 600 kpa at 3000 rpm when warmed up by running for 15 min at 1500 rpm. If below 300 change to heavier oil,  if above 600 change to lighter oil regardless of ambient range.
Change 6 months or 5000 km and 800ml of old oil stays in sump - need to remove sump to extract, leave unless removing engine.
 
I Use semi-syth, change yearly or if it changes colour. 
I  change Santa fe' oil every 7500 instead of 15000.

In the end it comes down to what they deem suitable at a cost, this is why they allow you to choose your own oils as one persons use - needs -driving style - demographic region might require different or more advanced spec, it should be noted that not just Hyundai but all car brands and dealerships do this with their oil used and it's consumers preference of choice to either stick with what they provide or go above recommended.

Dunno about this - I think they allow you to choose your own oils as it's YOUR car, so they can hardly pull a Henry Ford and say you can use any oil as long as it's the one we say.

Lets be candid - 99% of folks don't want to stuff around with looking at oil ratings and the rationale behind them - 90% of them trust that the dealer will use the CORRECT oil for their car inline with the maker's recommendations.  And so they're trusting both the dealer and the maker to have integrity, technical knowledge and common sense.

But in this case I think the maker isn't showing that - and in those examples you gave it seemed you were implying the dealer isn't showing integrity as they're using cheaper stuff that didn't meet the Hyundai specs - again as I said you're talking petrol and for your car so I've no idea what that is - but I'd not trust the dealers if left to make the choices for you.

So you'd expect/hope they were using the 100% correct stuff but I think there's clearly - atleast in this case a fair bit of doubt over that. I've not been shown a single bit of evidence to the contrary and I've put up a crapload of stuff showing that it's highly questionable that 5w-30 is the right oil for these cars in Australia.

And to be fair you're going into stuff that is off tangent from what this thread is about - my central point is why is this particular oil grade recommended and actively pushed on consumers for this car, when evidence shows it's a questionable choice at best and the same company has a different policy in other markets - those questions stand.

Beyond that, sure if the consumer is doing some 'special' stuff then how is the dealer/mechanic to know that and so they'd only be able to use what the maker (and lets just stay on this one rather than generalising across the entire industry as that tends to make the discussion even more of a mess) recommends - so you'd hope the maker is correct. 

All those oil's I mentioned other than the A5 were also suitable for light diesels

To be exact they might be suitable for SOME light diesels, they're not suitable for all (i.e dpf fitted) - but again we're getting off tangent. Anyway hopefully I'll hear back from Penrite soon, perhaps a real oil boffin is lurking in here who can assist and I might even try and see what Hyundai say and how they explain the USA vs Aus policy difference.

[CraigB]

All those oil's I mentioned other than the A5 were also suitable for light diesels

To be exact they might be suitable for SOME light diesels, they're not suitable for all (i.e dpf fitted)

I did say "were" and they were suitable for all petrol and light duty diesels and used exclusively across the fleet, "were" also being pre-DPF which I failed to mention as I was referencing what Hyundai did in the past before I chose to use my own oil.

[Purplehazeffc]

While fuel dilution does happen. It is not a great concern as a lot of people make out.

This is an oil sample taken from a Skoda Superb. Which has VW EA888, 2lt direct injection, turbo engine.
The oil had done 13,998 klms on the 5w-30 oil.  After that the fuel in the oil was 1.09%
When tested the oil still identifies as a 5w-30 oil. So not dropping down any viscosity.  Again it is in Russian.
Suprotec Atomium 5W-30 ????????? ?? Skoda Superb ????? 13 998 ??. - ???????????? ??????? ????????? - ?????????? ????????? - ????? oil-club.ru - ?????

My SR change intervals are every 10,000ks, which get done at the dealer. I change the oil at every 5000k's.  Using 5w-30

More constant driving will help with fuel dilution. As longer running at operation temp will allow the fuel in the oil to vapour off.
But if the vehicle is only used to go down the shops & drop kids off at school etc, and the engine not getting up to operating temp.
Then there is less chance of the fuel to vapour off.  And more fuel gets into the oil when the engine is cold. Due to be a more richer mixture.
And the pistons & rings haven't expanded, due to the heat.. So a car that only does a 5-10 minute drive, while looking at having low K's
Is worse off than a car that drives for about an hour with more K's. As most people just service their car by the book, or even slightly over.

It's no different with diesels fitted with a DPF. The engine & exhaust needs to get to a certain temp for them to re-generate.
Only drive short distances. Then the DPF won't get to temp. Then you have them having problems like blocking up..

Why did the USA put out a notice on going from 5w-30 to a 5w-40 ??   Maybe in general cars in the US only drive short distances..
If really interested maybe contact a US Hyundai dealer & ask them why.

And another oil sample from a Skoda 1.4lt TSI. Turbo, direct injection. Where the car has done 38,000k's
The sample of oil has done 8,300k's with Shell HX8 5w-30 being used.
Shell Helix HX8 ECT 5W-30 ????????? ?? Skoda Octavia A7 1.4TSI ????? 8300?? - ???????????? ??????? ????????? - ?????????? ????????? - ????? oil-club.ru -

Again Fuel is present in the oil to just over 2%.  But the oil still identify's as a 5w-30.  And no wear is shown.


So I think what comes out of this..   Is use a good quality fully synthetic oil. And change it regularly.
Keep to your manufacture specs.  But is doing more IE:  Track day work, heavy towing.  Then go up from say 5w-30 to a 5w-40

[pidim]

Doesn’t engine temperature remain constant, regardless of ambient temp?

[The Gonz]

By design there's an optimal running temperature, much higher than ambient, regulated by the heat exchange of radiator, pump and coolant. However, there is a practical limit to its effectiveness and efficiency, which is why we have temperature gauges to warn us of sub-optimal conditions.

This isn't to tell you to suck eggs but to walk through the logic to make your point. Based on that same logic, unless my temperature gauge is reading higher than usual, I wouldn't feel the need for a higher-rated oil.

[mickd]

By design there's an optimal running temperature, much higher than ambient, regulated by the heat exchange of radiator, pump and coolant. However, there is a practical limit to its effectiveness and efficiency, which is why we have temperature gauges to warn us of sub-optimal conditions.

This isn't to tell you to suck eggs but to walk through the logic to make your point. Based on that same logic, unless my temperature gauge is reading higher than usual, I wouldn't feel the need for a higher-rated oil.

@The Gonz
Right you are Gonz 
90 deg is deemed usual, check thermostat temps. (Can get 60 deg for hard working workhorses.)
Short trips etc listed as abnormal/ severe  conditions in owners manual, thus adding a new set of values.

Based on that same logic, unless my temperature gauge is reading higher than usual, I wouldn't feel the need for a higher-rated oil.

What you're saying makes sense - however, lets just assume there was no existing oil weight recommendation out from Hyundai Aust - you seem to come from ADL, a tad hotter than where I live mid-NSW - how would you rationalise to someone that 5W-30 was a superior choice for them than 5W-40?

As I just cannot see based on either Hyundai's very rudimentry Recommended SA Viscosity Number diagram in the user manual - which states and I'll directly quote ," ...higher viscosity engine oils are required for satisfactory lubrication in hot weather. "
"When choosing an oil, consider the range of temperature your vehicle will be operated in before the next oil change."

Now just allow me to be clear - I am ONLY talking about applications for DIESEL engines - as the temp ratings for those are COMPLETELY DIFFERENT (5W-30 is rated up to 50c ambient for petrol ONLY).

But for diesel it clearly shows that 5/10W-30 oils are officially recommended only to be used up to 40c operating temps.  I mean if that isn't clear cut I really must be missing something completely and like I said I don't pretent to know the in's and out's of oil tech but I don't think there's much to know with that as it's very straight forward.

Then you add on top of that the brilliant internal Hyundai Technical Service Memo that was very kindly shared by @Purplehazeffc and that adds another level of gravity to the above logic being concurred with by Hyundai themselves:
Engine Oil viscosity grades - logic vs Hyundai recommendation

As in short is says, "We previous said use 5W-30  but instead use 5W-40 - and if you don't do this you might damage your engine as you're not following what we said - and this would void your warranty."

@The Gonz with that in mind and being that you live in pretty hot ADL why is it you'd feel the 30 is a better option that the 40 weight?  Serious question - am not looking to be PITA - as I am sure you know more than myself and I'm just trying to see what i'm missing. :-)

[The Gonz]

@The Gonz with that in mind and being that you live in pretty hot ADL why is it you'd feel the 30 is a better option that the 40 weight?  Serious question - am not looking to be PITA - as I am sure you know more than myself and I'm just trying to see what i'm missing. :-)

I wouldn't accept that I know more than you - that would be step one on a path to no learning.

I simply take the observation that the 30 is deemed adequate while considering the 40 better. But the advice out there is a minefield, some saying the viscosity of the 40 adds to the work the engine does, while at the same time saying it provides better start-up penetration. I don't how you can have both when comparing the 30 and 40 both at 5W. In the end, I suspect maintaining viscosity at temperature isn't the only consideration behind the recommendations.

As I say in my STEM lectures, though, you can't argue science when faced with all the facts.

I wouldn't accept that I know more than you - that would be step one on a path to no learning.

I'm being polite - I'm new here and the last thing I want to do is tell old salts I know better. :-)

I simply take the observation that the 30 is deemed adequate

Well it seems that it WAS (past tense) deemed adequate, but that memo from HACC shows thats no longer the case - and like I said given that diagram and info in the user manual it's clearly not adequate for most of Australia. 

I would go as far as to say it's downright irresponsible for Hyundai to use it given that it seems to directly contradict them own info and recommendations.
I really get the feeling people are defending it so strongly as it seems they've always had it used and on some level don't want to concede that it likely isn't the appropriate weight for the temperatures we face for an Australian Summer.

But the advice out there is a minefield,

Well I have been trying to keep things simple and more meaningful by dealing with only the info put out by Hyundai themselves - if we go saying 'well someone said we'd get nowhere at all.

some saying the viscosity of the 40 adds to the work the engine does,

The first statement is correct but it's in no way a 'negative' thats why studies have shown a 30 oil uses up to 1% less fuel than a 40 weight. So thats basically the entire and only benefit of 30 vs 40.  So if you want that instead of having your engine protected anytime the temp is over 40 - and bearing in mind 40 is the recommended MAX for 30.....so you'd be pushing that a lot in an average summer - especially in high traffic, built up areas where the on road temps are much higher.

while at the same time saying it provides better start-up penetration.

My understanding is thats incorrect - the 5W (as there's 30 & 40 in 5W) is their viscosity at startup - so for all intents and purposes they are identical.

Like I said I get the feeling a lot of folks are very protective of the 5W-30 oil that they've been using on the basis that Hyundai chose to put it in so it must have been ok to use - I'd ask folks put that to the side and look at the temps you drive in each summer, the Hyundai recommended viscosity chart and that HACC memo where they plainly said do not use 5W-30 anymore - and then say why they feel 30 is still the better choice. :-)

[pidim]

By design there's an optimal running temperature, much higher than ambient, regulated by the heat exchange of radiator, pump and coolant. However, there is a practical limit to its effectiveness and efficiency, which is why we have temperature gauges to warn us of sub-optimal conditions.

This isn't to tell you to suck eggs but to walk through the logic to make your point. Based on that same logic, unless my temperature gauge is reading higher than usual, I wouldn't feel the need for a higher-rated oil.

All good. I’m no mechanic, just wondered.