I have a ZZ4 engine that I got out of a car that I bought. I had some water loss issues when I got it. Today we pulled it out of the car and took off the intake. When we took the intake off I noticed that there was coolent on the gasket around the water passages. I knew that I had coolant in the block but until today I was unsure of where it was coming from. When we drained the pan coolant came out of the drain for several seconds before oil came out.
There was a lot clumps in the oil when it came out, just like in my friends grand am before it blew up. His engine had water in it too. There was some sludge in the lifter valley and in the pan and all over the reciprocating assembly.
So my question is do we have to have the engine torn down and have it cleaned, or is it ok if we just wipe out as much of the water oil mix and put it back together then change the oil shortly after reassembly? The engine while I had it didnt run for very long after I noticed that I had coolent loss.
I dont want to tear the engine down, but I am worried about bearing failure. As far as I know the engine only has about 20k miles on it.
Also should we pull the heads?

 

I'd take the pan off and have a look at the bearings. It would be a bigger PITA to put the engine in the car and set it all up just to have the thing lock-up and pitch a rod out the side.

The old saying "Measure twice, cut once"