Hello all,
My '89 Jetta 16V has been losing a little coolant for a while - reservoir
level would go down about a half inch every few weeks. But now, it's a
little worse, and I have a serious oil leak - drip, drip drip only when the
engine is running. When I got under the car all I could see was a coolant
drop on the bottom of the fat coolant hose that runs up towards the oil
filter - saw nothing coming from the water pump. The oil is oozing out from
somewhere in behind the oil cooler, and running down over the front of the
pan.

On my old '86 Carat, the oil cooler gasket was broken. What else could
cause such a leak only when oil is circulating? Before I take off the oil
cooler, I'm wondering if there's any way I can test or check to see if the
cooler itself is damaged, causing both coolant and oil loss. Bentley says a
faulty oil cooler can cause leaking between coolant and oil systems.

Do I need to drain the oil and coolant, or can I get away with just taking
off the filter (I'll lose what, a quart?). Is it just as easy to drain the
coolant and check all the hoses while I'm at it, and refill?

Thanks
Theo

"Theo" <drideout (AT) umich (DOT) edu> wrote

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


"Jo Bo" <jromas (AT) columbus (DOT) rr.com> wrote

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.

On Sun, 11 Jan 2004 18:27:33 -0500, "Theo" <drideout (AT) umich (DOT) edu> wrote: