First Post Before I Pull The Engine
 

Hi all,

I recently purchased my first car, a 2001 Porsche Boxster S with a 6-speed Manual and 103,000 miles on it, and it is completely stock.

I bought it knowing that it has problems, and my dad and I will be handling all of the work ourselves. What we knew when buying it was that the oil flows into the Coolant. Since then, we've found that the Cooling system doesn't hold pressure, and while under pressure, we can hear it venting in the Crank Case. There are no leaks in the Oil Cooler. We have also done warm engine Compression and Leakdown tests; here are our results.

Cylinder --- Compression --- Leakdown Loss (@ 90 PSI)
1 --- 140 --- 6%
2 --- 160 --- 4%
3 --- 150 --- 6%
4 --- 150 --- 2%
5 --- 140 --- 3%
6 --- 145 --- 2%

From reading all the other posts in the community, our primary suspect is a cracked head.

I would like to ask if anyone has suggestions for more steps before we pull the engine. Thank you in advance; excited to be a new part of the Forum.

How did you test the cooling system for holding pressure and where were you listening that you heard coolant going to the crankcase? You have drained the oil and found coolant in it? Compression while not great isn't that bad and within margin of error considering testing/gauge differences. The leakdown is fine.

Perhaps your water to oil cooler..?
 

Hello George, before you pull the engine you may want to check first that the O-rings on the oil cooler are in good shape as these could cause intermix as well.
Good luck!

Thank you both for your replies, we checked the Oil cooler O-rings, and they are in good condition. We used a cooling system pressure tester to test the cooling system. We were never able to get it to hold pressure, and it required a constant flow of air; to hold about 14 PSI, we had to flow 25.

During the pressure test using a scope, we could hear air loss primarily from the area of the crank case. We only had oil in the coolant, never the other way around.