Chrysler Repair: 2004 PT Cruiser: water/oil pan leak

Question
QUESTION: I have a 2004 PT Cruiser with a 2.4 engine that has water coming out of a cracked oil pan when you pour water into the thermostat housing.  Why?  What will it take to fix this?

ANSWER: Hi Cricket,
The oil and the water coolant systems are supposed to be isolated from one another. So if water is coming out of a crack in the oil pan then that isolation has been breeched and water is getting directly into the oil pan. The systems are adjacent to one another but still not in contact in the engine block and  engine cylinder head so now there presumably is a leak across from one system to the other. This could be due to a cylinder head gasket leak, or it could be a crack in the cylinder head or the engine block which allows the systems to interconnect. It sounds like a significant experience occurred which caused some damage.
Was there a specific history as to when this started? What caused the oil pan to crack? Did the engine overheat suddenly? Did you see steam coming out from somewhere on the engine?
Let me know more.
Roland

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QUESTION: Roland,
There is a crack in the oil pan to the right of the oil filter if you are under the passenger side of the car and it is down about a half inch below the lip of the oil pan.  The thermostat was frozen shut when the car over heated and died.  It would not restart at first, but restarted after about ten or fifteen minutes, only to over heat again and die.  The heater fan had been blowing cold air before dying the first time and did not overheat until I turned the heater fan off.  After dying the second time we got it to cool down, got it started, and turned the heater fan on and made it to the house(approx. 5 miles) before it began overheating again.  There was nothing coming out from under the car when I shut it off at home.  I do not know when or how the oil pan got cracked.

Answer
Hi Cricket,
It is difficult to know what has gone wrong inside the engine except to note that there is some sort of a signicant leak between the cooling system and the oil system. If you check the oil dipstick does it show an overfill, and is there evidence of foam in the oil either of  which would represent a significant amount of water is in the oil pan. I would expect that the engine will need to be opened to inspect for cracks in the head or block or for a head gasket leak between the oil and the water passageways. You could begin by using a pressure gauge at each of the spark plug holes to see what the compression readings are on the four cylinders and thus get an idea of the extent of the damage without doing much work to take it apart. The reading should be about 100 psi and within 25% of one another.
Roland