On my 2001 S40 Turbo when it starts cold there is a chirping sound coming from like underneath the car. All the guys over 60 that have heard it say it sounds like an exhaust issue. I took it to my mechanic and he also thought exhaust but because it would stop after the car warmed up a minute he suggested it could be some kind of pollution control valve that only runs when the engine is cold on European cars. He wasn't sure if this one had one but said to bring it back when he had more time. Anybody got any ideas?

 

With the engine cold remove the heat shield over the turbo and check the nuts on the exhaust studs to see if one or two have backed off. My 2001 used to loosen up every 6 months or so and make a noise until it warmed up. A stop nut fixed it for good.

 

Thanks... I'll try that.. is this shield the turkey pan looking thing on the firewall? Did you noise chirp at every revolution of the engine? Hope it is this simple.

 

Lol, that heat shield does look like a cooking pan for a turkey but it's not the one I'm talking about. It's the one on the back of the engine above the turbo and exhaust manifold. It's held in place with 3 bolts. Once removed the exhaust manifold is pretty easy to access. When the engine is cold you can feel the nuts on the exhaust studs. The furthest one towards the driver's side gave me problems.

Mine sounded like the classic sewing machine sound of a leaking manifold. A chirping sound, to me, means metal on metal. A dry bearing or maybe the A/C compressor. A leaking manifold is an easy fix. Metal on metal is very bad usually. A mechanic's stethoscope can help pinpoint a noise with the engine running. You can also use a rubber hose held to your ear. Move the other end around the engine bay to find the source.

 

Glad I ask about the turkey pan I might have pulled the wrong one.

The chirping sound I mean is probably a bad description. More like a whistling sound (think George Jetson's car). And it only does it for a minute or less at startup. I'll try to get out there this weekend and figure it out. Might have to make a video if I can't.

 

I Think it occurs because the engine is cold .



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there is probably a chipmunk living under car and hes getting pissed because of the fumes when you start car. im no mechanic though, just my 2 cents. sorry, couldnt help it. seriously , it could be the belt.

 

I have a 2001 S60 that makes a noise when driving that sounds like a belt is humming. I just had he timing belt assembly replaced, but it's still pretty loud....especially when driving on the highway. My car used to be quiet as a mouse and now it's loud like a machine is running outside. Has anyone encountered this problem? Thanks.

 

Does the sound get louder when the engine is revved up? If so, you could try this. Remove the serpentine belt then start the car and see if the noise goes away. If the noise goes away then put the belt back on and try to pinpoint the source. Power steering pump, alternator, and compressor all run off the belt.

If the sound does not get louder as the engine is revved up then it's more likely in the drive train. Axles, transmission, wheel bearings, etc.