i just bought a 97 dodge caravan with the 3.0 about 3 months ago and on my second oil change i noticed a significant amount of water in the oil. the next day i drove 15 miles each way to advance to purchase some stop leak and by the time i got back i had to dump it and change it again. what is typical with these vans? head gaskets? cracked cylinder heads? or should i just do some exploritory surgery on it?

 

Fill the cooling system and pressure ck. If you don't see any coolant or water on the ground, then you may have a blowen head gasket. Remove the spark plug with the pressure tester still under pressure a crank the engine, if you have coolant getting into the cylinder it will push the coolant out the spark plug hole.

 

Do you have white smoke/steam coming out of the exhaust pipe?
This points to the coolant leaking into the cylinders. Blown head gasket,cracked head.

Coolant in the oil and nowhere else can be a couple of things. Cracked head or a blown head gasket.

Either way an engine teardown is probably in your future.
Is there any warranty time left?
Does the seller have any kind of liability? A dealer would have a some amount but an individual is pretty much in the clear.