Bad turbo? or good ol' rod-knock?

[turbo4toy]

Hey there, I was hoping to get some advice from you guys about a diagnosis of a problem.

Last night on my way home from work and I heard a faint knocking noise. I was looking at all of the posts about rodknock and saw the different ways to check for that. (Which I have not done yet) The only reason I think that it might be something else is that I have a leak right by my turbo and it appears to be coolant. It was buring the coolant off right away before the car was even close to warm it had idled for probably 1 min. I took my intake off and there is very minimal shaft play and the fins don't appear to be damaged. The last time I had a crazy noise like that the turbo I has was hitting the housing and died. Anyway, the only other thing I can think is possibly if the gas is bad or low octane.

You can hear the noise at about 2k RPM but not really above or below that. Sounds good at start-up as well.

Its probably just wishful thinking but is it possible the turbo is bad or do I more likely have a BHG with a side of rod-knock.

Luckily I have a spare head and block that are in good condition so even if it is the worst case I have some extra parts to get it out on the road again.

Any advice or tips are welcomed.

 

[7Mboost]

If you had rod knock it would get louder the higher rpm's you reach.

 

[aye mate]

If you had rod knock it would get louder the higher rpm's you reach.

I don't think that is totally true.

You are gonna need to do some testing before anyone here is going to be able to help you out that much. I've never heard of a dying turbo making a knocking noise. The leaking coolant sounds like it could be from the coolant lines for the turbo. They tend to crack because of the heat in that area of the engine bay. Like I said you are gonna need to do some testing before you can call it rod knock. It could be valve noise also.

 

[boosting185]

could be a wrist pin or piston slap..bad gas...what is your oil pressure?

 

[7Mboost]

I don't think that is totally true.

You are gonna need to do some testing before anyone here is going to be able to help you out that much. I've never heard of a dying turbo making a knocking noise. The leaking coolant sounds like it could be from the coolant lines for the turbo. They tend to crack because of the heat in that area of the engine bay. Like I said you are gonna need to do some testing before you can call it rod knock. It could be valve noise also.

If you have rod knock and are increasing the speed (rpm) of which it is spinning it will only hit the block harder and get louder...right?

 

[turbo4toy]

Well........
It is definitely not the turbo the motor is siezed.

 

[7Mboost]

Well........
It is definitely not the turbo the motor is siezed.

Ha that sucks, did you drive it and it locked up, or would it not start and figured its seized?

 

[MmmBoost]

rodknock (if minor) will only be audible at around 2000-2500 rpm and whenever oil pressure is low (start up). i drove mine like that for 6 months before it took its final shit.

when it gets bad, it makes a scary noise, and eventually the motor wont run.

 

[turbo4toy]

It won't start and it makes a metal on metal sound that lightly jerks the car when i tried to start it up again.

But it's hard to say exactly whats wrong until i take it apart.

 

[supramike7m]

i had a similar sound happen to mine, sounds very similar. i thought it was rod knock. it ended up being my flywheel bolts came loose and was flopping around. but it sounded alot like knock. take off your inspection plate and have a look, its worth a look.

 

[IJ.]

If you have rod knock and are increasing the speed (rpm) of which it is spinning it will only hit the block harder and get louder...right?

Wrong!

Early on in a Rod Knock motor when RPM increases so does Oil pressure and the knock goes away........ for awhile!

 

[turbo4toy]

i had a similar sound happen to mine, sounds very similar. i thought it was rod knock. it ended up being my flywheel bolts came loose and was flopping around. but it sounded alot like knock. take off your inspection plate and have a look, its worth a look.

Did it make the sound while the car was still while revving the engine? Its worth a shot either way I suppose.

 

[supramike7m]

yes it did. just check it out, its worth a look

 

[turbo4toy]

yes it did. just check it out, its worth a look

Was it totally obvious when you had the inspection plate off? Was it so loose you could wiggle it by hand or what? I'm taking a look at it today.

Forgive me for asking this if it is totally impossible but can a starter get stuck or jammed causing the car not to start or run? or any other advice of things to look for without totally taking the top end apart?

 

[supramike7m]

yep it was pretty obvious if was just wiggling around, and it made the car hard to start, cause sometimes when the flywheel was toward the starter it would start but when it would wobble the other direction it wouldnt start.

 

[turbo4toy]

Ok, so upon further investigation I have a BHG and there is coolant in my oil . There appears to be a leak on the exhaust side as well. Anyway, I am wondering If I change the HG and flush all of the coolant/oil mixture from the engine is there a chance my rodknock will go away since it is very slight. Or do I just need to do a total rebuild? And I got the car to start I don't know why it wouldn't before but the flywheel and everything is tight.

 

[PROJECT N00b]

i dont think the knocking of the rod will ever go away.


DUN DUN DUN!

 

[Tim]

That is the exact symptom that I had. The knock would only be present at about 2500 rpm and would not be their under heavy load or when the car was not warmed up. It ended up being rodknock!!

 

[yrallofthenamestaken]

Ok, so upon further investigation I have a BHG and there is coolant in my oil . There appears to be a leak on the exhaust side as well. Anyway, I am wondering If I change the HG and flush all of the coolant/oil mixture from the engine is there a chance my rodknock will go away since it is very slight. Or do I just need to do a total rebuild? And I got the car to start I don't know why it wouldn't before but the flywheel and everything is tight.

Rebuild.

 

[F_T_F]

look at the oil when i had my rod bearing go i saw metal flakes in the oil, then again i drove it for longer then i should have before i finally pulled the engine and rebuilt it.