Whistling at idle... - United Bimmer Community

**Kistoni** · 08-15-2006, 10:22 PM

I ve run out of luck down at the steelership...

Been chasing a whistling noise from under the hood

The vacuum tube had perished and turned to sponge so that has been replaced, but now the crankcase breather valve is letting air in (tried cleaning it but seems it needs replacing) and there is still a whistling noise that stops when the engine is under load.

I have removed the icv a couple of times and cleaned and oiled it but not helped. Perhaps this is shot and needs replacing too?

Cant find any other holes in hoses or bellows.

Replaced the gaskets on the TB and induction flange. Replaced ac belt (cracked), replace water pump (was still good) and pulley guide and tensioner (both good still) but the noise remains...

Steeler is doing well out of this one but has no idea what is the problem.

Any ideas before I run out of $$ and the misses murders me?

**xsperf** · 08-15-2006, 10:31 PM

if u rev up, whistle goes away? and is it a whistling or a whining?

**c1apton** · 08-15-2006, 11:16 PM

Replace that crankcase breather valve & check for more vac leaks. A vac leak will drop (in sound) when under load because you're equalizing the outside pressure with the internal - actually just lowering it. At idle is when vac pressure is about at it's highest and if it's whistling you have yourself a vac leak whether a hose, injector, head gasket.map gasket _ Does it idle rough?

witeshark · 08-15-2006, 11:31 PM

^^^ Good idea, and also maybe a crack leak in the intake bellows to the manifold?

**Kistoni** · 08-16-2006, 02:21 AM

The noise is more of a whistling and it usually only comes when the engine is warmed up and idling.

**Kistoni** · 08-16-2006, 02:27 AM

yes idle is a bit rough and runing a bit rich. noise stops on rev up / load.

I am fairly sure vac leak but how to find???

**c1apton** · 08-16-2006, 05:44 AM

Take and spray propane around areas in question while the car is idling and the idle will immediately rev slightly & momentarily when you discover the leak(s) Your local hardware store should sell these home soldering kits with small bottles of propane. Just use one of those kits and DON'T light the propane.

**Kistoni** · 08-16-2006, 03:15 PM

thx will try and let you kno

**Kistoni** · 08-17-2006, 07:09 AM

went to stealership and out of stock on the breather valve + other bits i need so will try to get them myself...

not sure if propane in the vacuum system would make the engine rev as this does not flow into the cylinders.

**c1apton** · 08-17-2006, 07:38 AM

Quote:

Originally Posted by Kistoni

went to stealership and out of stock on the breather valve + other bits i need so will try to get them myself...

not sure if propane in the vacuum system would make the engine rev as this does not flow into the cylinders.

Engine vacuum is created by the cylinders. It's the same vacuum (low pressure) that assists your brakes and vac operated switches and valves on the engine. What do you think powers your "mpg meter" on your dash?

**RSF5** · 08-17-2006, 11:28 AM

Quote:

Originally Posted by Kistoni

Steeler is doing well out of this one but has no idea what is the problem.

Man their taking your money even when they can't find the problem. United BMW stopped charging me when they couldn't figure out my leak and then when they did they only charged me for the part.

**Kistoni** · 08-18-2006, 08:19 AM

Quote:

Originally Posted by RSF5

Man their taking your money even when they can't find the problem. United BMW stopped charging me when they couldn't figure out my leak and then when they did they only charged me for the part.

yeah feels like bum deal... its takes them weeks to get over priced parts too

at least they haggle

**Kistoni** · 08-18-2006, 08:28 AM

is that so. I guess I thought it was powered by the intake manifold?

thanks for the education

sprayed some anti squeal on the belt today but definately not that.
will take off the belt tomo to check alternator and ps bearings.

forgot to mention whitsling continues after turning off the ignition for about 2 - 3 secs.

**dinan540** · 08-18-2006, 08:53 AM

Kistoni, good luck with the noise. How irritating.

I just returned from Fiji on my honeymoon this week. What a beautiful place, my wife and I will return again in the future.

**c1apton** · 08-18-2006, 11:17 PM

Quote:

Originally Posted by Kistoni

forgot to mention whitsling continues after turning off the ignition for about 2 - 3 secs.

It's probably dieseling (running on) after you turn off ignition. That's another idication of a vac leak. Get in there with a good light and inspect every hose - vac lines, intake hose - look for cracks, broken etc...