[aranciataoz]

Hi there ...

Just after some advice ... our i30 Tourer diesel has done 127,000km of trouble free motoring. Aside from upcoming trailing arms that will need replacing at some stage, our mechanic sometime last year advised me there was quite a bit of oil buildup on the engine block.

Careful investigations by myself after I degreased everything clean, revealed one (or maybe more) of the bolts fastening the inlet manifold to the engine block, has been weeping oil - refer photos below, especially 3rd photo.

I'm assuming it's diesel that's leaking not engine oil (well I'm hoping not!) given there has not been any significant drop in engine oil levels; as well based on the (excellent) topic below of gunk from EGR impacting the manifold:

The impact of the EGR system on the intake manifold of my 2012 i30 diesel.

I'm wondering what investigative steps to undertake ... basically do I get my mechanic to embark on hours of removing the manifold for an inspection and clean for what is potentially quite a normal occurrence (of oil weeping)? In other words is this normal? Or am I not cautious enough ie. have it investigated ASAP given it could be a turbo related issue? (the turbo does seem to be working fine).

In terms of performance symptoms, when the throttle is floored, and the gear changing down, I do notice from the rear vision mirror quite a bit of black smoke from the tailpipe for a few secs - again, I can't recall if this is no greater than when we had the car 7 years ago when it was only 24,000kms. I just noticed it more in the past 2 years, and am wondering even if the end result of the manifold clean does not reveal any major issues, the cleaned manifold might result in better airflow under full throttle (I read somewhere the black smoke under full throttle is often an overly rich fuel mixture, which I'm guessing can also be exacerbated by lack of air).

Anyway I'm after suggestions, especially from the gurus of the EGR topic above @Fireescape @nzenigma 

[zatos99]

Diesels tend to be dirtier than petrols. My mate has a Hilux who had a similar problem to you, "oil" leaking somewhere from the block, I also have had oil leaking from my intake manifold at a slow rate. The seal around the turbo shaft isn't perfect and let's some oil in to the air flow, that seems to be normal in diesels, hence why the new Hilux's blow "blue" smoke which is oil due to the turbos overworking.

Possible sources of oil from intake direction: It could very well be turbo related, one way to check is look inside the intercooler or even easier have a look inside the tube that goes from the intercooler to the engine, if there's excessive oil then it could be turbo, you can get your mechanic to have a look at it (take intake hose coming from MAF off and wiggle the shaft. Highly unlikely for 127kms that there's any significant play). There's a vid on YouTube about a mechanic who sees lots of iLoads and iMaxs blowing turbos (i30s have very similar turbos btw) and he said the best thing to do is replace the copper washers on the injectors every year as they degrade and let combustion gases into the oil which reduces the lubricating effect, which is bad for the turbo

Other things it could be: bolt tension on manifold, manifold gasket. Both are unlikely but problems like these are soul destroying if you can't find the problem haha.

Good luck

Disclaimer: I'm not a pro, but I've had an i30 and all their (usually minor) issues for 7 yrs

[aranciataoz]

Thanks so much for this @zatos99 ! I’ll chat with my mechanic about these - personally I’d love to take all this apart and do it myself but with two young kids and now in lockdown it’s a challenge to just breathe sometimes! But very helpful pointers mate!


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