Help please - loud high pitched noise from engine bay

[mtk540 3]

OK so my wife used my car tHis evening to go look at a open home. I'd just got home from work so the engine is at its correct running temperature.

She arrives home some 45 minutes later and backs up the driveway, the car making this awful high pitched squealing noise. At first I thought it was the fan belt but nevertheless got her to shut down straight away. She said "your brakes are making a funny noise". WTF?!!! "It only made that noise when I was braking or when I had the brakes on when we were stationery...". OK so at low revs or idle. Obviously not the brakes then.

"Sorry darling, not the brakes." Lifted the hood and started up. High pitched noise coming from rear of the right bank (as we are looking at it) of the V8. Rev it and the noise diminishes in sound but speeds up in frequency. Sounds like a rotating part touching something. Engine temp seems OK hovering at mid point on guage as had radiator replaced two weeks ago so coolant levels should be optimal.

Anyway I may wait until the engine cools and start up again.

In the meantime, any thoughts? I am a total non mechanic so wouldn't know what to look or listen for.

If its still making that noise tomorrow morning shall I run the risk of driving to my mechanic in rush hour traffic?

Cheers

Mike

[CSET 564]

Sure it's not a drive belt Mike? Otherwise could be tensioner or pulley? I've read up on this a little, there's a couple of people offshore who've reported a similar noise on the e39 540 and it's turned out to be the water pump.

[*Glenn* 854]

Possibly the PCV valve. Try releasing the oil filler cap slightly and raise it a little and see if the noise goes away. If it's that loud though you might not be able to release the cap with the suction on it. If necessary, use both hands to raise it.

[mtk540 3]

Let it cool down last night and it idled fine.

However... on the school run she started that dreadful noise again. A bit embarrassing at the school drop off zone. Anyway I made it to Kevin Burt's and Kevin, as always, was very obliging and tried to sort it straight away.

At first he thought it was a slipping belt on a pulley - yes Christian, good googling - so sprayed some magic stuff on. Noise gone. About to drive away and then "Wheeeeeee !" WTF, again. Kevin suggested I leave it with him as the suspect pulley was buried under the water pump.

Once on the hoist it was diagnosed as a broken crankcase ventilation valve - Glenn is that the same part that you are talking about?? THis is located at the back of the engine, where I thought the noise was coming from in the first place. He showed me the part and the gasket was shot as was the valve and the casing was cracked. May have been a large stone from one of Chch's many cr@p roads that smacked into it - who knows. Apparently as the valve was shot, the vent inside was vibrating against the casing making the noise which, when under load, would stop vibrating.

All good now, running real nice and smooth.

Mike

PS: Christian - thanks for lunch the other day! Will reciprocate when next in AKL - actually next Wed but just a quick day visit.

[*Glenn* 854]

Let it cool down last night and it idled fine.

However... on the school run she started that dreadful noise again. A bit embarrassing at the school drop off zone. Anyway I made it to Kevin Burt's and Kevin, as always, was very obliging and tried to sort it straight away.

At first he thought it was a slipping belt on a pulley - yes Christian, good googling - so sprayed some magic stuff on. Noise gone. About to drive away and then "Wheeeeeee !" WTF, again. Kevin suggested I leave it with him as the suspect pulley was buried under the water pump.

Once on the hoist it was diagnosed as a broken crankcase ventilation valve - Glenn is that the same part that you are talking about?? THis is located at the back of the engine, where I thought the noise was coming from in the first place. He showed me the part and the gasket was shot as was the valve and the casing was cracked. May have been a large stone from one of Chch's many cr@p roads that smacked into it - who knows. Apparently as the valve was shot, the vent inside was vibrating against the casing making the noise which, when under load, would stop vibrating.

All good now, running real nice and smooth.

Mike

PS: Christian - thanks for lunch the other day! Will reciprocate when next in AKL - actually next Wed but just a quick day visit.

Yes...same part. PCV valve = crankcase ventilator valve = oil seperator valve. They can get real loud at times when they fail

Edited March 14, 2013 by *Glenn*