Hi,

03 STi has just been mapped...running fine but gradually getting this PPSSSSSS noise (air escaping) while coming on boost,been getting worse and worse... so...

I put on a new jubilee clip on the turbo intake,and checked everywhere for leaks...and only found on the intercooler one of the cast pipes is leaking oil...(see pic) it's leaking from the gasket and running down and onto the red turbo output hose. is this a big enough leak to be giving me this grief or am I looking for something more serious?

everything appears fine,I have sprayed carb cleaner on every joint/connection and what have you but I get no rpm increase or decrease.

when we were mapping the car I got a smell of oil but we passed it off as being one of the wagons...

here's the pic...thanks

 

bump

 

Bumping the thread after an hour is taking the p*ss a bit, not like it was off the bottom of page 1, was it?

Are the bolts securing the inlet flange to the intercooler tight? Provided they are, and provided the gasket is still in one piece (have you taken the Y off to check?), there shouldn't be a significant air leak from there.

Your mapper has presumably seen a bunch of cars so what was his/her opinion of the cause? Was the leak sufficient enough to impact the turbo's ability to generate boost?

 

well excuse the eagerness,but I'm so fed up...at the verge of selling this car.

I'v had the inter cooler pipe work off,all gaskets are in place,and i'v nipped up the bolts...

we had no real problems mapping it...apart from 5th and 6th a bit of compressor surge..but as I drove it the next day...it got worse and worse.


when I say it's leaking oil...there is a small puddle/damp spot where it's been running down and dripping off the red outlet hose...

 

Obvious question: Are you sure this is a boost leak, or is there an alternative cause for the noise you haven't so far considered?

 

well i'm not sure...

around 2800 rpms this hissing noise comes in and get's louder the more revs,and the car doesn't pull as well as it did after mapping.

what other causes could there be?

 

could a leaking de-cat at the turbo caus a significant drop in power,and how the turbo is spooling?

 

I'v just had the airbox lid off and back on and looked around for anything obvious,and it seem's to have cleared up considerably..so maybe the airbox lid wasn't on to well...although it seemed to be.

now it's a slight whistle and a flutter when coming on boost...would the inter cooler gasket leaking be able to caus this?

 

I've had to replace those gaskets before mate.. they are only a few quid from subaru.

 

You can repair the leak, just clean up the joint and reseat with sealant. It can also be the DV leaking.

 

Hey,

did replacing them help your problem? i'v been quoted 33 quid inc vat from montys in Sheffield,that's for the 2 inlet gaskets and the re circ valve gasket.

thanks,

 

I put a bit of gasket cement on it yesterday which didn't seem to help any...I think the gasket cement was crap tho...my dad has had it for almost 15 years haha

 

If the bolts are tight I would be very surprised if those gaskets were responsible for any audible leaking.

However as far as gasket cement is concerned, you'll be wasting your time simply daubing it on the exterior of the assembled joint - especially when we already know there's oil leaking through it. This applies whether the sealant is 15 years or 15 days old.

If you have an intent to seal it properly you'll need to disassemble the joint, properly clean and degrease it, and then reassemble properly. If you use a liquid gasket, it must be on the mating surfaces, not applied to the exterior.

Although, provided the Subaru gasket is in good condition, there should be no need for liquids of any sort - and they're best avoided in areas like this anyway. If the proper part is degraded, the best fix is a new one as 2000 Sport says.

Provided all the bolts are done up properly, both on these connections and the DV flange, and provided the gaskets are in reasonably good nick, you won't find significant leakage from them.

 

hey,

the gaskets are fully intact,no damage to them at all...I did apply the cement to the mating surface...not just blob it on the outside.

if it's not one of these joints...where else should I look? turbo inlet seems to be ok... airbox lid seems to be on right.

 

gaskets are at my dealer's now,picking them up tomorrow...

is there anything else I can check while I have it in bits tomorrow? I'm going to have a real good look at the inter cooler hoses,anything else?

 

all new gaskets on the IC and hasn't helped one bit...

I'm beginning to think the car is just over boosting a little early maybe and it's just blowing off the boost.

a hope a map tweak will sort it.