MrLexse

I just found a thick film of oil in the coolant reservoir tank. The engine seems to be loosing coolant rapidly, with no signs of steam at the exhaust pipe. No signs of any water in the engine oil (dipstick). I haven't done a compression test or leakdown test yet. Could this be something minor?

Randy V

Sounds like your radiator has failed.

The radiator shares a cooling loop with the auto trans. You are seeing transmission fluid in the coolant.

First step is to immediately check the trans for coolant infiltration. If present, the trans must be thoroughly flushed out to prevent additional damage to it.

ErnestSw

DO NOT START THE CAR BEFORE YOU HAVE THE COOLANT AND OIL DRAINED, THE TRANSMISSION FLUSHED AND THE LEAK REPAIRED!!

MrLexse

The car is a 5 speed. Would that warning still apply?a

Fastest928

Oil in the coolant is not as bas as water int he oil

Pressure test the radiator quckly...chances are a failed internal oil cooler.

Marc
DEVEK

bd0nalds0n

How much coolant is lost r"rapidly?" I have a mysterious coolant disappearance problem, about one expansion tank-full every 300 or so miles. But I've never had any residue in the expansion tank, and I don't have any milkshake in my oil (although there is a little steam-like residue on my filler neck when I take off the oil cap). Would this also be a symptom of radiator going bad? I can't seem to find any other leaks...

Garth S

Just a slight addition to Marc's good call - the 5 bar pressure oil leaks to the 1 bar pressure coolant when running; however, when shut down hot, the coolant remains pressured and can migrate to the oil loop - so also do as Ernest notes - drain the sump: a precaution is to toss a rag over the 'rad' cap and release the pressure.
A toffee coloured gel or foam under the oil filler cap is a result of emulsified oil/water - check there as well.
bd0nalds0n - is this the stuff you're seeing?

MrLexse

Yeah, the emulsified oil/coolant is toffee colored. The coolant loss is about 1/2 the reservoir in about 20 minutes of run time. It's actually faster than that, but I'm scaring myself.

Mark- Is the internal oil cooler in the radiator itself? Does this cooler apply to a manual transmission ?
I have a pressure tester but I'm not sure how to test the radiator, as it has no outlet.

Garth S

The internal oil cooler is in the left (drivers side) rad tank: The oil lines can be a real PITA to disconnect - counterhold the tank fitting with a 27mm, and the gland nut releases with a 32mm.
With these lines off (the fans and shroud assembly may have to be moved), put the pressure tester in place of the expansion tank cap and pump it up. If coolant comes out of the now open oil cooler nipples .....

MrLexse

Thanks for the info. I'll give it a shot

heinrich

Very common and others have stated correctly that oil in the coolant ain't no thang ... as long as that's all. Very likely the silly radiator end-tank common failure. 944's have this failure in their oil cooler on the block. Seems you'd expect a separate cooler huh

bd0nalds0n

Yeah, I have the toffee colored gunk at my oil filler cap/neck. My leak isn't nearly as bad as MrLexse. Probably time for a new radiator, see if that fits the bill. I saw at Sharktoberfest that 928Int'l was coming out (i think) with their own version. Hopefully it's less than the OEM, which I think is, what, around $900 bucks?

SharkSkin

I've been very happy with my Devek radiator, and it's a LOT cheaper than the Porsche unit.

Garth S

Just to note, a pressure test as described earlier might be worthwhile doing prior to commiting to a new rad.

On another direction, would it not be easier to cap off a leaking oil cooler, and mount a seperate oil heat exchanger under the condensor in front of the rad?? This would save the rad - and oil coolers of all sizes are readily available.

perrys4

I was told the new oem unit is like 1700.00 + install.....