[Keith]

Gee you are very enterprising Keith (quite the back yard mechanic) 

I love saving money Daz! I calculated a short while back that tackling stuff myself, on 8 different cars, over the last 8 years has saved me around £5k at dealership prices around £90 / hour! Thats just lights & general electrical problems, brake pads / discs & shoe problems, suspension, EML's etc... if I had the facilities for doing exhausts, clutches etc I'd have saved around another £1k I reckon.

[Surferdude]

Banging the dash doesn't make any difference. It doesn't induce it nor get rid of it.
When you pull up and turn the motor off, the noise goes away, about 2 seconds AFTER the ignition is swithed off.

[Keith]

Banging the dash doesn't make any difference. It doesn't induce it nor get rid of it.
When you pull up and turn the motor off, the noise goes away, about 2 seconds AFTER the ignition is swithed off.

Thats different then, sounds like interference from one of the control systems under the bonnet. The alternator stops almost immediately when you shut the engine off.
When its really quiet one evening... run the motor or open the bonnet with the motor running and stick ya head under by the engine... secure all loose and hanging clothing first!
Get someone to switch the engine off and you will hear what I'm talking about... something runs for a few seconds after switch off other than the cooling fan. When I say "runs" I mean runs electrically... you can hear it... but I dunno what it is yet!

[Phil №❶]

Of those with radio probs, can we identify diesel or petrol or both 

[constipated]

A bit more info on my problem.

I have a diesel.

Actually what I said in an earlier post is not true. I too have the interference continue once the engine is turned off.

When I know it's happening  (ie usually as I pull into my carport, where the slightly reduced signal brings out the interference), I then switch off the engine but am still in the ACC setting so radio still plays. The high pitched whine immediately starts dropping it pitch going from high pitched to a low drone, and then reverses and starts to go up again. There is an associated clicking noise too. This can go on for several minutes before fading away.

I don't know what sort of electrical device can generate the ongoing interference after the engine goes off.

At this stage I am willing to accept that it is a faulty noise suppressor in the radio.

[Phil №❶]

OK, diesel, well that rules out ignition systems then.

Even when the car is switched "off", electrically it's still "on" The Body Control Module remains activated in order to handle door locking when the key is removed, and lock / unlock from the key. This can be hours or days apart even, so it is always energised.

The BCM is effectively a computer, with a processor which will emit RFI. AM radio is susceptible to this type of interference. The BCM is located in the interior of the car AFAIK. It's my bet this is the culprit.

I also remember reading on here somewhere a long time ago about other things in our cars that remain on but I can't remember what thread it was

[constipated]

Second new radio is going well so far. This one was new. I had to remove the protective plastic from the display.

In problem areas like my carport where the radio signal is probably weaker, occasionally on start up I get the high pitched whine but now this disappears within about 3-4 seconds and doesn't come back.

So I guess possible faulty noise suppressor in the radio was the problem.

Hope it doesn't come back.

[Dazzler]

Thanks for the update con.. (fingers crossed)

[Doggie 1]

  & eyes too.