Milkshake-Oil Cooler or head gasket?

[Paul Glasson]

Not happy-Yesterday when I went to check water level in coolant resevoir I found it half full of thick milkshake. Car was running fine, no smoke out tailpipe and oil pressure gauge ran at 1 bar at idle and 4 bar at 2-3000rpm after about 5km travelling. There is no sign of milkshake on dipstick and what I would call normal small signs of cream colour on oil filler cap with a few drops of condensate.
Apart from doing a compression test is there any way to determine which of the two is the cause? Phoned a mechanic who does much of the wrenching for local club members and he thinks it probably is the oil cooler that is leaking. He also says he removes the heat exchanger in the oil cooler claiming it is not neccessary in our average daily climate of 25-30 deg centigrade.
What do you guys think. How long would it take to do this repair and flushing of cooling system for an experienced mechanic? Says it will cost about $430(R3000) to repair without replacing heat exchanger.
thanks

[dwise944na]

It sounds like the oil cooler gasket. It is not hard work, just a little time consuming. There are great instructions at "http://www.clarks-garage.com/" under the heading of garage shop manual - Oil Cooler General Information and Seal Replacement. Be sure to clean everything really well before reassembling it. All the parts you need are listed in the header of the oil cooler and seals section here at Pelican Parts. The total parts shoudn't be more than $25 plus shipping.

You probably have the 3 piece oil pressure relief valve (oprv) like I do. It is critical that you get that lined up correctly when you put it back in. There is a tool for it, I think it is $21.

Good luck

[Razorback1980]

I agree with dwise944na...USUALLY but not always, the head gasket will also put compression in the cooling system and cause it to run hot or hotter than normal. Sometimes you will lose coolant because of a head gasket as well, so I'm thinking it's the oil cooler seals. I would do the oil cooler seals first. The thing to watch for is rod bearings. Any time you mix coolant and oil, you stand a chance of damaging the rod bearings but if you change it early, then you are probably okay. After you change the oil cooler seals, change the oil as well just to make sure there is no coolant in there. I also strained my used oil through a white t-shirt to see if there were any small pieces of rod or main bearings in the oil. If there is, you may have to do more than change the oil cooler seals. The key is to catch it early and fix the problem. The price quoted to fix the oil cooler seals doesn't sound too bad considering the amount of time it takes, but the option to do it yourself is always open as well.

[Slam]

I'd agree about the oil cooler seals failing, and Porsche recommends that if there's been any mixing of oil and coolant that the rod bearings be changed. If there's no coolant in your oil when you drain the oil pan then consider yourself lucky but keep a very close eye on your engine.

Changing the oil cooler seals is a pretty easy job, but you must have the alignment tool.

Good luck with this!

[Porsche-O-Phile]

If it's in the cooling system it's most likely the oil cooler gasket. If you have coolant in the oil it's probably the h.g.

Think of it this way - it's relatively easy for 4-5 bar pressure oil to force its way past a bad seal and into a relatively low-pressure coolant passage under normal conditions. For low-ish pressure coolant to force its way into relatively HIGH pressure oil passages, it needs some help - like what's present in the cylinders due to a h.g. breach.

[Paul Glasson]

Thanks for the info. I am taking the easy, more expensive way out and having it done and at same time changing the balance shaft and cam belts as they have 40000km on them. Oil will also be changed. Does anyone know about the modification to remove the oil cooler element?? This mechanic says it is required more in cold climates to help warm cooling water rather than being required to cool the oil,if I have the story right! He repairs a lot of the 944 & other expensive club cars, has had a number of 944's including a 944 Cup car presently so I do believe he knows his story.
BTW.I had the car loaded on a flat bed and carted the 30km to this mechanic rather than risk damage to bearings or overheating by driving. A few bucks spent now rather than mega bucks later!

[Porsche-O-Phile]

Replacing the oil cooler gaskets is not hard. I recently did it on my "daily driver project" that's now almost complete. I recommend pulling the radiator off the car and flushing it as well as you can. Even so, you'll probably have a couple of coolant system flushes to get all the residual milkshake crud out of the system. I plan on doing this in a couple of weeks (once I start driving the car regularly) and then again a couple weeks later. By that point I expect I won't see any more blobs of milkshake crud and can put "good" coolant in (right now just distilled water and a flusher/cleaner solution).

I would absolutely spend the 30-or-so bucks and get the oil pressure relief valve alignment tool. It makes re-install a heck of a lot easier.

[Slam]

I'd leave the oil cooler element in place. It's a heat exchanger and one of its functions is to help the car warm up faster when it's cold. I live in Canada and sometimes drive my car in -35C weather (ducks behind flame-proof barrier) and it's fine, warm-up wise. In fact, it warms up quite quickly.

[Paul Glasson]

Originally posted by Slam
I'd leave the oil cooler element in place. It's a heat exchanger and one of its functions is to help the car warm up faster when it's cold. I live in Canada and sometimes drive my car in -35C weather (ducks behind flame-proof barrier) and it's fine, warm-up wise. In fact, it warms up quite quickly.

Don't know the exact conversion to farenheit but i think it was something like -32 deg F = 0 deg C so the average temperature here would probably be 57- 62 deg F. We never have snow here on the coast and seldom see temperatures as low as 10 deg C and that was the mechanics reasoning for leaving it out. Apparently the element is quite expensive and he says leave out if not neccessary.

[mbwilser]

From my experience:

Coolant can definately (seen it w/ me own eyes) leak at the cooler into the oil w/ little or no oil passing into the coolant. After partial disassembly while starting to remove my oil cooler, I drained the radiator, removed oil filter, and took a break for the night. Well the next morning, I find a puddle of coolant on the floor. Guess where it is coming from? The oil filter housing, the center portion that feeds the filter.

I have heard the pressure argument before, that the oil is under greater pressure than the coolant, so herego the oil will leak into the coolant prior to coolant into oil. This sounds reasonable but is not realistic. Let's consider the engine immediately after shutdown, Oil pressure is zero while the cooling system is under pressure. Or when the engine is cold, neither system is under pressure, but isn't the coolant more likely to find its way past a bad seal at zero pressure than 20-50 cold oil. Thats what I saw! Zero pressure condition w/ coolant dripping into the oil!

So to all that proclaim the oil will leak into coolant prior to vice versa, I disagree. seen it , lived it, and cleaned it.

Not trying to stir the pot, just trying to dispel myths.

Mike

[Razorback1980]

Mine did the same thing. More coolant in oil than oil in coolant. I currently have it torn down replacing all seals and bearings because of this. Hopefully it will be back in the car this weekend. The crazy part was when you check the oil, it looked so clean and there was very little trace of coolant on the dipstick, but when you pulled the oil plug it wasn't hard to see at all....which is why I requested he change the oil and strain it for bearing pieces. If you have bearing damage after the leak, you can look for it to spin a bearing shortly which is a much more costly repair. I took the safe route and I'm just replacing mine plus it was time for all new seals anyway.

Not sure what your climate it like but if it's like Slam's or mine it is good to have an oil cooler, I just wished Porsche would have done it like the 911's and made it air cooled instead of water cooled. One of the few mechanical designs I think Porsche screwed up on this car. On my Ford trucks, they have oil coolers also but they run water through a housing that the oil filter attaches to but the difference is the water comes from the outside and there is no seal that separates the two fluids so there is no chance for a leak. Much better design than Porsche used. In my climate where our coldest weather is 35F, oil coolers do just what they say...they cool the oil to help lubricate better. They are very functional and you probably should keep it, but it's just a very bad design.

[Slam]

Looks like things can go either way with equal aplomb. Mine leaked oil into the coolant. Kinda thankful it was that way round...

[Paul Glasson]

What was going to be a +/- $430 job has been increased almost three fold. On removing timing/balance belts for replacement a slight leak on the oil seal for camshaft was found and seal replaced, and cambelt tensioning roller and idle roller replaced. I am glad that was found in time, as all these could have caused belts to break. As he was doing belts and oil cooler had the major service. Front discs were worn below limits. Could have let that go a bit, but in for a penny in for a pound so now front discs and pads are being replaced.
This car is regularly serviced every 10-15000km and by mechanics approved by the local club. The last two garages were not predominately Porsche service centres though. So approximately $1660 later I have to evaluate whether I really can afford to run a Porsche (except by doing my own wrenching for which I do not have the right garage space and lacking the in depth knowledge). There is another way of looking at things. Buying an almost new medium range car, paying the Hire Purchase and Insurance would probably cost more than the average monthly maintenance of the 944, and it would not be as much fun. Try explaining that to the wife who has other priorities required around the house. At least those I do most of my own repairs.

[rudidelange]

Paul
Sorry to hear about the leak. I found that Alpha (or Alfa) disks from an earlier 911 fits a 944 - exact specs - except its 0.5mm thicker and Ferodo pads. Alfa disks are made in SA. Dont feel too bad, my initial weekend, $100 job in December turned out to be a seven month $1500++ job - and after that I broke an inlet valve@#$%. Still buzy attending to that.