Unusual Noise Coming From Turbo Side Of Motor

[R32_GODZILLA]

Hey guys

A few days ago i noticed an unusual noise coming from my motor after as soon as it cranks over on a cold start. Within a couple of seconds after the motor has cranked over this weird humming/grinding noise was apparent.

On cold start it is very audible (sounds like a cow mooing), when revved increases in pitch, quiets down somewhat after a few minutes then once warm it is very quiet/not even noticeable. Last couple of times I've started the car in the mornings I've left my bonnet open to find the source - It seems to be coming from the turbo side of the motor if not the turbo itself.

I'm hoping the turbo isn't eating itself away as a couple of weeks ago I've installed a manual boost controller and set it to 12-13psi (stock RB20 turbo) - car is still boosting fine to 12psi, goes exactly as hard as before i heard the noise so it's got me scratching my head.

My car has turbo-back exhaust, fuel pump, front mount, filter, ecu remap.

I'll be taking my car to my mechanic so he can have a look at it in the next few days but just want to see what people on here might think this could be or have had this sort of problem before.

Cheers,

Steve.

[ZILR-34]

sounds like shaft play. turbo is on the way out mate. best way to check take off the inlet pipe and see if u can pull and push the turbo wheel in and out or sideways. then u will know 4 sure. then save up for a gcg highflow

[R31 POWER]

My sisters 32 is doing the same thing! It may be cas bearings but i will have to check that out.

[teng]

sounds like shaft play. turbo is on the way out mate. best way to check take off the inlet pipe and see if u can pull and push the turbo wheel in and out or sideways. then u will know 4 sure. then save up for a gcg highflow

How much push and pull to tell if the turbo has shaft play? If it's just a little, does it mean turbo is on it's way out? I guess the tubo wheel must not be able to move in and out correct?

[R32_GODZILLA]

sounds like shaft play. turbo is on the way out mate. best way to check take off the inlet pipe and see if u can pull and push the turbo wheel in and out or sideways. then u will know 4 sure. then save up for a gcg highflow

Yeah that was my first thought once i heard the noise - i'll get it checked out properly so i know that it definately is. Looking for an RB25 turbo replacement for the moment - No high-flow as of yet

My sisters 32 is doing the same thing! It may be cas bearings but i will have to check that out.

Possible i guess, but didn't sound like it was near there on my occasion - More middle manifold i.e turbo. Sucks. I'll try get audio or something.

[Psymon]

I had a similar problem... turned out my a/c pump was shagged!

[R31 POWER]

Turns out it is the cas. I did the old screw driver tip on it while holding the handle in my ear It's noisey as fark. The noise must travel thru the cam/rocker cover (in my sisters case) because it sounded like it was coming from around the turbo/head area.

[R32_GODZILLA]

Hmm thanks to everyone for their input

I haven't had time to get it properly checked out but since i've posted this up the noise has disappeared. No cold/warm start noise like before and car is still performs the same - all well and good. Hope it doesn't come back.

Ahh well, still on the lookout for a better turbo though

Cheers

Steve.