small coolant leak, big oil leak - oil cooler?

Unless you've already replaced your hoses your coolant leak is most likely a hose problem. Unless you've got coolant in the oil your cooler is most likely good. You might find it easier to replace the leaking seal between the cooler and flange by removing the filter then the pipe like thing that holds it all together. That makes it easier to slide a new seal in without messing with coolant hoses. These seals seem to fail more often in the winter when the oil is thicker.

Jo Bo

Thanks. It's cold here in Michigan, so I may just do the o-ring to stop the oil leak. What you say makes sense, the coolant leak is likely a hose because if the cooler failed internally then coolant would get into the oil, not leak in a separate bright green stream. BTW, compression very good and consistent across all cylinders so head gasket is good.

Theo

story time I was changing the thermostat in my 91 Passat 16V, engine temperature would go down to cold while driving on highway.

I drained all of the clean coolant out and after I took the thermostat out, engine oil started to come out of the water pump housing via that oil cooler hose. I did not have any coolant in the oil, that I could tell. Nor any oil in the coolant, that I could tell.

I replaced the oil cooler, deciding it was the only thing that could cause this problem. So far after 2K miles all seems good. Knock on wood! lol

Usually the plastic coolant pipes on the cylinder head deform, crack and leak over time. Or heater core goes bad and you may see leaks either inside of the vehicle or under the car by the cat. Or the water pump leaks.

later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris

Here's my CDN$0.02. Are all the plastic coolant flanges in good shape? Coolant leaks are always fun to diagnose as they run in hidden rivulets usually on the backside of the hoses.

Darryl.

So I changes the oil cooler gasket, and oil is still gushing out. Turns out it was the high-pressure switch that screws into the top of the oil filter flange! Never would have thought. The 1-post, white plastic one with the hex nut. The oil was coming out from where the terminal is sunk into the white plastic. $6 and a lot easier than changing the gasket.

Coolant leak was worn hose - the three-headed monster that costs $37. Automotive Goop will hopefully hold it until it warms up. Reminds me of Ottawa here right now.

Thanks Theo