Coolant and oil mixing

[cobra1379]

Ok first please don't say I have a busted block or something major.

I have an 02 4.0 4x4 xlt non flex explorer wrecked. Rear ended a truck busted the radiator and pushed it into the fan no other damage noted didn't even break the fan. Drove it up on a trailer drove it off trailer and maybe 50 yards. Sat 2 years.

Bought 05 same specs but flex fuel. Put 02 motor in 05 using everything from the 05 that I could. Put everything on except front accessories. Started and ran maybe 10 seconds. SWEET!!! Put accessories on added Coolant. Water pump leaking. No big deal kinda expected. Pull pump. Oily sludge NOOOOO. Pull dipstick same. Everything switched over the same except for the oil cooler/heater core lines. Anyway something there is crossed? Any other ideas??
Had antifreeze in it when it crashed and the hood was always shut so I don't think water could have gotten into it to freeze anything. Don't think it hit anything hard enough to bust anything in the wreck. I could forcefully spin the fan before cutting the radiator out and free spun afterwards. No bent pulleys or anything. The oil filter did hang up a little when I pulled it but just a small dent in it. Thanks

 

[rmunley]

Sounds like leaking head gasket or intake manifold gasket leak. Those are probably the 2 most common causes of oil/coolant mixing. I also think I remember reading once that oil and coolant both pass through the thermostat housing assembly. Might also check there for cracks etc.

 

[Bobmbx]

While the truck was sitting for 2 years, did it have coolant in it, or was it dry?

Sounds like some gaskets dry-rotted. I'd say a head gasket.

 

[lincolnshibuya]

your oil filter adapter has both oil and coolant passages, better check that out for any major damage since both fluids can mix at that point.