Engine Noise - whistle

[DPG]

Evening all

I wonder is someone could shed some light on a noise that i have. I've taken my car to a local garage for a quick look but they couldnt find anything wrong.

The noise is like a high pitched whistle and it only happens when driving with very low revs (1st, 2nd gear and reverse) and when the engine is up to normal running temperature. Never happens when the engine is cold.

The local mechanic could only suggest (without furthur investigation) that it's some sort of valve that could be on its way out.

It doesnt seem to have any affect on the performance, its just a bit annoying when setting off or parking up. :?

Cheers

DPG

 

[srhutch]

Have you had an oil change recently?

I had a similar issue turned out the oil filter wasnt seated correctly

 

[DPG]

The noise was there before my oil change and is still there after.

I asked the Indy that did my oil change to have a look. They could hear the noise but could find anything wrong or where it was coming from.

 

[Shipkiller]

Open your bonnet, and perform a inspection of your rubber intake pipe using your hands. This is the pipe that runs from the engine to the air box. I bet you will find a crack somewhere on it. Most likely on the small tube.

http://www.realoem.com/bmw/showparts.do?model=BT33&mospid=47798&btnr=13_0995&hg=13&fg=15

Number five on the drawing....

 

[Shooter]

I also have a whistle on my car, which only occurs when i put the gas pedal to a certain position, let say 1/3 of the way when i accelerate. It happens at all revs, all temperature... if i accelerate a bit less, no whistle, if i accelerate harder, no whistle.
My guess is that the air flowing through the engine intake is making that noise when throttle flap is in a certain position only.
Or could it be that there is a leak somewhere, but only at a certain air pressure/speed ?

 

[DPG]

Open your bonnet, and perform a inspection of your rubber intake pipe using your hands. This is the pipe that runs from the engine to the air box. I bet you will find a crack somewhere on it. Most likely on the small tube.

http://www.realoem.com/bmw/showparts.do?model=BT33&mospid=47798&btnr=13_0995&hg=13&fg=15

Number five on the drawing....

I thought it could be that too but the noise was still there once i'd installed my Sound Generator which comes with a new Rubber Boot :?

 

[Shipkiller]

Make sure your boot is seated against the throttle body correctly....

Another member on this forum had the same noise and that was his problem.

 

[Aebous]

I also have a whistle on my car, which only occurs when i put the gas pedal to a certain position, let say 1/3 of the way when i accelerate. It happens at all revs, all temperature... if i accelerate a bit less, no whistle, if i accelerate harder, no whistle.
My guess is that the air flowing through the engine intake is making that noise when throttle flap is in a certain position only.
Or could it be that there is a leak somewhere, but only at a certain air pressure/speed ?

Do the same thing that Shipkiller said. Most likely you have a small crack probably on one of the intake hoses commonly on the #5 part as Shipkiller pointed out. There has been quite a few of us on this forum that have had to replace #5.

Open your bonnet, and perform a inspection of your rubber intake pipe using your hands. This is the pipe that runs from the engine to the air box. I bet you will find a crack somewhere on it. Most likely on the small tube.

http://www.realoem.com/bmw/showparts.do?model=BT33&mospid=47798&btnr=13_0995&hg=13&fg=15

Number five on the drawing....

If that isn't it, check all the lines you can see that deal with air.

 

[DPG]

After another test today with someone else pressing the gas pedal, the noise seems to be coming from the area around the oil filter housing.

Any ideas?