Exhaust Leak?

[karmakaze]

ok, so my car is making ****ed up noises.

sounds like a huge exhaust leak or the turbo going bad, something along those lines. gets worse as the engine revs, and the car drives like its having a lot of resistance.

so i took my turbo/exhaust manifold off. can't find any leaks. manifold has no cracks, turbo has no play. however, the turbo shaft is very stiff. it does not spin very freely. i spin it and it maybe goes around a few rotations.

there is no abnormal oil buildup.

i still don't see how that could cause that much racket.

so i link my oil inlet and outlet and start the car. i guess it sort of sounded like the noise i am describing, but not really. i don't know what a car without headers is suposed to sound like. i should of recorded the noise before i took it apart. but i just figured it was an exhaust leak or cracked mani.

i did chop off a length of water hose to snoop out the sound and it did seem like the noise was coming from my turbo. no noise from the head or exhaust mani.

help!!!

any ideas?

[Silvia007]

First off... zerothread?id=158599

Loud knocking noise (I assume) that increases with RPM and engine running sluggish.

If my description is correct, it's probably a spun connecting rod bearing.

If not, or atleast we hope not, it may be leaking from the turbo manifold where it meets the head.

[S13240]

Most likely an exhaust leak.

Silvia007 has it right on the dot. Check your exhaust gaskets.

[karmakaze]

First off... zerothread?id=158599

Loud knocking noise (I assume) that increases with RPM and engine running sluggish.

If my description is correct, it's probably a spun connecting rod bearing.

If not, or atleast we hope not, it may be leaking from the turbo manifold where it meets the head.

well there is not an exhaust leak. i will however double check tomorrow. that sucks... thanks.

[Nismo_Freak]

Make sure your exhaust wheel is still there.

[karmakaze]

i have. at the moment i actually have the entire exhaust manifold, turbo, and downpipe off of the car.

[karmakaze]

ok, i replaced the exhaust gaskets. no change. problem is still there.

could it be the turbo?

i started it up again today, and using my ghetto stethoscope (a piece of water hose), found that the noise is the loudest after the exhaust turbine. however, unhooking the wastegate does not affect the sound.

the car runs like crap. has no power, hardly spools, and bucks up like its not getting fuel if you try to give it gas. does make "thwapping" noises after you give it gas and the rpms go down.

exhaust smells fine. oil looks fine.blowbye is normal.

i just had the turbo out, and it seemed fine. no oil or shaftplay. i find it hard to believe that it would be a spun bearing. the inside of this engine is spotless.

I am going to get a real stethoscope to try to pinpoint it better.

you guys still think it is a spun bearing?

[Blown240sx]

A Spun bearing in the motor will cause a noticable KNOCK and will probably only occure during certain RPM ranges not through the whole powerband. You wont confuse it for anything else. If it is a bearing they arnt terribly hard to replace but you have to pull the motor. If you dont replace it youlll be in a world of trouble.My buddy is replacing his 1 and 2 rod bearings at this moment.

If its an exhaust leak it will sound, and smell like it.

Most of the things your talking about are noticable problems without help of tools.

If your not positive on what it is Id go ahead and pull th motor and double check everything. Better to be safe than sorry.

[karmakaze]

A Spun bearing in the motor will cause a noticable KNOCK and will probably only occure during certain RPM ranges not through the whole powerband. You wont confuse it for anything else. If it is a bearing they arnt terribly hard to replace but you have to pull the motor. If you dont replace it youlll be in a world of trouble.My buddy is replacing his 1 and 2 rod bearings at this moment.

If its an exhaust leak it will sound, and smell like it.

Most of the things your talking about are noticable problems without help of tools.

If your not positive on what it is Id go ahead and pull th motor and double check everything. Better to be safe than sorry.

Its not an exhaust leak. I have elemenated that. It happens through the entire power band above idle.

[karmakaze]

well i had someone i know who has a bit more experience with engine internals than me take a look at it and they said it sounded like a problem with one of my exhaust valves and that one might be burned up. they also pointed out that my 02 sensor had a crushed wire on it.