whats this noise ?

[JohnzY]

hey I need some help figuring out what this noise is that keeps comming from the engine its louder when the car is colder and slowly goes away when car gets warmer sometimes still there when car is warmed up too and i was wondering what the noise is

Ive taken the car to a couple mechanics they told me could be a exhaust leak or bad turbo or bad bearing inside turbo or even a vacuum leak

what do you guys think this could be from ?


here is a video showing the sound when I rev the motor

[Weehe]

Your video doesn't work. If it is a high pitched sound, could be the secondary air pump going. (since it is on cold starts mostly). You can check the turbo by pulling off the TIP and feeling for play in the shaft also.

[JohnzY]

sorry if that video didnt work here is the link with the video on youtube let me know if this one works.
thanks

[vdubb3dan]

cam chain tensioner.

[JohnzY]

if it were the cam chain tensioner wouldnt it still make this noise after the car was warm and even if i were to rev it slowly this is only happens if i tap on the gas youll hear it if i were to slowly rev it you wont hear it and also you hear it when the turbo spools while driving and you can hear that sound like as if it were spooling so that kinda makes me think its the turbo

[scotts13]

It's not the typical CCT sound but it's still more likely to be that than the turbocharger. I don't see the turbo making ANY sound that low pitched.

[JohnzY]

anyone know what this could be ?

maybe exhaust or vac leak ?

[IanInOhio]

Do a sea foam test in the vac system and let it run through. If you have an exhaust leak you should see it. If it's a vac leak there's a chance you won't see it, so run a vac test. It sounds like it's coming from the turbo / manifold / cat area, not the back of the engine. Get real close and listen for the sound and determine exactly where it's coming from.

It really just sounds like air is doing something it's not supposed to, so I think it's just a leak somewhere. Does it drive like normal otherwise?


---edit

Reason why I don't think it's your turbo at all is because is in order for your turbo to spool up, there needs to be a load on the engine. Just sitting there out of gear all of that air will go through the bypass and not spool the turbo. So you're turbo is good. Focus on the exhaust though it really sounds like a gasket is blown, but it's hard to tell on the video. So again, so a sea foam test.

[JohnzY]

did a boost leak test and no leaks and took off the intake hose and checked the turbo it has no play and non of the turbo fins were bent or anything like that so im guessing maybe a exhaust leak ?

and if its not a exhaust leak what else should i check ?

[IanInOhio]

Yea check your gaskets from block to manifold to turbo to cat to downpipe...

I had a very similar issue, but it would leak out a damaged gasket when under high boost. But same basic sound I had.

[JohnzY]

alright thank you yes i will check the gaskets for the exhaust and also the exhaust its self too to see if there is any leaks is there any way of spraying something onto the exhaust to find leaks for the exhaust or the only way of doing it is either a smoke machine and sea foam

[IanInOhio]

Sea foam would do the trick. Use about a third of the can through the vac lines, stop the engine as soon as it's done with a third of a can (pour it into a separate cup so you can regulate how much goes in the engine) for about 5 minutes so it can break down any particles. Then start her up, use either a brick or a friend and have the engine rev to 2-3000 rpms and look under the hood and body of the car to see any smoke. With the engine reving like that there weill be plenty of smoke to see if you have any leaks. Also note that if it's a gasket, sea foam won't always be vi sable through the leak. I know in my case it wasn't, but when I pulled the gasket it was cracked quite a bit.

Good luck!

P.S. You might as well replace all of your gaskets since they're cheap and easy to do and will be one less place to check for leaks. Also remember to use a liquid sealant on both sides of the gaskets too to create a full bond / seal.