'00 S70 GLT, 150k:

I bought this car cheap, motor busted, and so don't know the history. It was driveable, but very rough. The guy said he'd continued to drive it for short distances after the motor started acting up.

I assumed it was a bad head gasket dumping coolant in the oil, but maybe not. Maybe it's the oil cooler? When I drained the sump there was over 3 gallons of coolant/oil chocolate milkshake. When I opened the drain plug the the coolant poured out first -- a lot of it hadn't mixed with oil yet. In other words, sitting around, the cooling system water drained right into the crankcase, and it hadn't mixed up into sludge. The coolant tank looks fine / no oil.

In the sump there was over three gallons of brown milkshake and unmixed coolant. (I started laughing when I pulled out the turbo-to-sump oil drain pipe and coolant started pouring out -- it was that full in the sump!)

Cold / slow-crank compression test showed 175, 170, 135, 150, 170.

The thing that got me to wondering about whether it might be something other than a head gasket: 135 isn't that low, and when I pulled the turbo air pipes off there was massive amounts of sludge in them too. I'm used to seeing a bit of oil in a turbo pipe, but this was like a full pint of goo. The turbo itself doesn't seem to have excess play in it. When I pulled the intercooler bottom pipe another pint or so drained out there. Maybe this is all a secondary problem, from having a clogged crank ventilation?

At any rate, here's a question: I see that the oil cooler just bolts on to the sump, with inlet and outlet ports on the sump. To test it for leaking I thought I'd bolt the cooler back to the sump, pull the hoses off it, plug one and pressurize the other. Yes?

Is it common to find coolant in the sump on this kind of scale?

Any other possible cause, besides head gasket or oil cooler?

For what it's worth, I'm pulling the head regardless, but I don't want to do all that work and find out I missed something.

Thanks,

 

It usually only has that much coolant when the headgasket blows or the oil cooler blows out.

 

Okay, good to know. Thanks.