Oil in the water....

[Evoluzione]

I think i'm typing this out as some kind of therapy after a long day and i'm going to be against the clock tomorrow as the car is booked on a track day on Saturday, but see what you think.
It's a 2ltr turbo pushing 500bhp and has been built about 5 yrs now although only done about 6 - 10k miles of road and track.
I built it so I know it was done properly, block & head refaced, ARP M10 studs n nuts, Cometic MLS gasket being the salient points.
After a bit of final testing this evening it came in spewing oily water out of the water exp tank overflow, it hasn't emulsified.
There is no water in the oil at all. The engine was running fine, all temps ok, oil pressure fine - despite there being not much left! It's pumped about a litre of oil out in less than 10 miles.
So you're thinking head gasket failure? My first thought, but it's got a combined water and oil rad. It's worked very well over the years, but i'm wondering if it's sprung a leak between the oil and water coolers.
I think i'll be taking the rad off and pressure testing it tomorrow, it's certainly the lesser of the two evils.
Any qualified thoughts appreciated.

[AdamIndy]

I have seen it happen before. Like you say, pressure test the oil cooler or blank off the coolant pipes to the oil cooler to see if that's the issue. Failing that, then compression test next and cylinder leak down test to see if it is the HG. I am not one to jump on the headgasket has gone bandwagon. 1 litre is a lot to lose in 10 miles.

Edit
If the turbo is water cooled, that maybe worth looking into as well.

[Piersman2]

My Boxster was doing this when I first bought, cracked cylinder head allowing oil into the water.

[stevieturbo]

Either are possible scenarios. You could try bypassing the oil cooler section for a while and see how things go, give the oily bits a good clean out.

Or pressure testing might reveal something too.

[Evoluzione]

Thanks all, the rad cap is right above the oil cooler where it sits inside the rad end tank so testing was simple.
I coupled the inlet and outlet of the oil cooler together with an air line, plugged it in and saw it bubbling up where i'd removed the rad cap.
So glad it's the rad and not the engine, just need to find a fix now....

[stevieturbo]

Evoluzione said:

Thanks all, the rad cap is right above the oil cooler where it sits inside the rad end tank so testing was simple.
I coupled the inlet and outlet of the oil cooler together with an air line, plugged it in and saw it bubbling up where i'd removed the rad cap.
So glad it's the rad and not the engine, just need to find a fix now....

post a pic, but depending how the two are combined, it may be a simple case of cutting the oil cooler bit off and welding up a new one.

Or just clean then plug it completely and run a separate oil cooler.

[Evoluzione]

stevieturbo said:

post a pic, but depending how the two are combined, it may be a simple case of cutting the oil cooler bit off and welding up a new one.

Or just clean then plug it completely and run a separate oil cooler.

It's ok Stevie, all done. After crying into my pint last night then having a good nights rest it was much clearer this morning (well after finding the leak!).
I flushed the oil cooler out and made up a link pipe between outlet n inlet. It's likely the pressurised water will find its way into the oil cooler (hence me cleaning it out), but not an issue right now.
I've bolted on a separate (original) oil cooler and Cinders, you shall go to the ball.
I wasn't too impressed at this all happening at the last minute, but if it had happened on the track tomorrow it would have been much worse.

[stevieturbo]

Just plug the two holes for the oil cooler bit, that way even if water does leak in, it will never go any further.

But it does look like you could cut that end tank off if you wanted and repair.

A proper dedicated oil cooler would be best though, usually an integrated one like that is more usually for trans fluid on a low pressure return line anyway