I have been trying to diagnose my STi v6's low boost prob for some time now with no luck, in the coarse of my diagnosis i replaced the factory Blow off valve suspecting a leak, but noticed oil in the intercooler when i removed it. My car has only done 12000km and has not seen a hard time. From where is it comming....is it normal.....Lastly Why does Subaru tell me my car is fine when it struggles to peak at 14psi and holds 13psi????
Please suggest.

Cheers

YY

I have also noticed oil in my intercooler MY97 when i replaced the hoses with Samco stuff, is it normal?, or should i/we be worried?

Please comment

Cheers


Iain

I also found oil in the intercooler when I had my Pulsar GTiR. I queried it with the garage that services my cars, and was told that a small amount of oil in the intercooler is normal and is nothing to worry about. Never had any problems with it.

surely you will always get oil in the intercooler as the oil breather system is plumbed ack into the inlet pipe. This means the oil vapour will have to travel through the intercooler before being sent back into the engine to be burned.

Since the intercooler is the most restrictive part of the intake system, you are bound to get some coming out of the fluid and collecting on the walls.

Is this where oil breathers/catch tanks are of use?

Will it prevent this from happening?

Cheers
Andy - Engine novice!

I had oil in the intercooler and suffered from on-boost puffs of smoke (only if the car had been off-boost for a while, i.e. motorway cruise followed by blast up the slip road).

Almost certainly caused by leaking oil seals on the impeller side of the turbo. If there is a problem here, then this also may explain your poor turbo performance - for example you may have lost a blade, reducing boost and putting it so out of balance that the oils seals have gone.

This is one experience, there may be other causes.

Trout

I found a bit of oil in my intercooler too...

not a huge surprise I suppose -the engine was rebuilt with Cosworth pistons (very noisy at start up) which generally use more oil (according to the people who service the car).

the only worrying thing is....

oil isn't known for its octane enhancing properties....

any thoughts?

Nick

Oil is coming from the beather system.

Cossies are renowned for this.. as are most turbo cars.

The Subie is fitted with a PCV which reduces oil vapour/polution at idle/cruise by sucking it back in, but on boost it blows back into the inlet system.

An oil catch tank system is required to eliminate the oil from the inlet.

Yes oil does lower the effeciency of the intercooler, and it also lowers the effective RON of the fuel.

J.