Coolant leaking into oil on a bastard T5 (99 S70 T5m)

[Levinicus]

I open the hood to find the coolant reservoir empty. I check the oil and find that the level is much too high and the color is quite wrong. My coolant is draining into the oil somewhere. I performed a cylinder leakdown test and have ruled out the head gasket. I have replaced the oil cooler, and yet the problem persists. The only remaining possibility of which I am aware is a cracked block, but I would think that this would a.) cause the car to fail the leakdown test (which it didn't) or b.) cause the car to run very poorly and throw codes (which it doesn't).

Am I wrong? Are there other places where the coolant and oil are in close proximity? Any seals besides the head gasket that could fail and cause mixing?

Thanks,
Alex

[rspi]

Turbo but it would smoke like crazy.

[j-dawg]

~never mind, you replaced your oil cooler already~

[wizechatmgr]

Crack in the head may still pass a leakdown test if it is beyond the combustion chamber and not through it.

[abscate]

I think its covered

- Oil cooler
-Turbo
-Block

Thats about it. Probably cylinder head over block - or maybe a weird water pump crack dumping into the block?

[Levinicus]

Crack in the head may still pass a leakdown test if it is beyond the combustion chamber and not through it.

Is that really possible though? Wouldn't any crack be caused by compression and thus intersect a cylinder?

[wizechatmgr]

You can get a hot spot such as when a vehicle ends up loosing coolant, air wasn't purged properly or the impeller isn't spinning with the shaft, you don't immediately notice and the head cracks. The compression itself doesn't actually cause the cracks there is usually another anomaly. Most issues with a head come down to heat, a lack of lubrication or incorrect/inadequate torque with exception of maintenance issues - burned valves, burned valve seats, valve guides, valve seals, etc.

Not all cracks on heads are into the combustion chamber or between valves. Seems to happen more with aluminum than with cast iron. The water jacket in the blocks are relatively hard to have an issue with, more times than not you'll find the issue in the head. Usually with the block more times than not the issue is caused by a lack of lubrication.

He could have a bad head gasket. My bets are on head gasket or head. The blocks tend to be reliable - odds are you would have already noticed other issues if the block was toast.

You could drain and pressurize the cooling system with air and try to track down the hiss with a mechanics stethoscope. Don't pressurize it beyond the existing cap specs or you can cause new issues. If you have young kids, don't bother, you'll never hear it...

[wizechatmgr]

A head gasket cannot 100% be tested just by a cylinder leak down test with this sort of issue... That only tests for the cylinders maintaining adequate compression - if you have a spot on the head gasket, the block or the head that is warped/pitted/cracked/otherwise bad that allows the oil passages and coolant passages to intersect you won't see that on a leak-down test UNLESS they are also leaking to the cylinder.

[MadeInJapan]

My son's 850 transmission was ruined because coolant got into his transmission through the radiator. A turbo radiator has oil, coolant and transmission fluid going through it...any one of these breaches and you have problems. How old is your radiator? That would be my guess if the other suggestions come up wrong.

[Levinicus]

Turbo but it would smoke like crazy.

Is it certain that the turbo would smoke if it were the location of the leak?