[brigham115]

Hi everyone -- I posted last week concerning a 1999 9-3 SE turbo (90k miles)with oil in the coolant (even after 3 coolant flushes). I took it back to the mechanic for retorquing the head bolts and a pressure test. Good news is there is no coolant in the cylinders and coolant isn't leaking anywhere else. But now what should I look for? Is there a transmission-coolant connection? How about a turbo-connection? Any help is greatly appreciated!

 

[JMarkert]

If you have an automatic, then there is a potential connection between the transmission oil and the coolant. There is an oil hose that goes through the radiator to cool off the transmission oil.

I've never heard of these breaking on this list, but on the Volvo list this was a common cause of oil in the coolant. If this is the case, I would be very worried about coolant going into the transmission, which could cause even more trouble. Also, I don't think oil is very good for the radiator hoses, so you might want to watch them with an eagle eye.

 

[Asia Skyly]

Wow! You learn something new everyday. The Manual Gearbox is absolutely, totally and completely independent from every other fluid in the engine.

 

[brigham115]

It is an automatic. 1 of the radiator flushes was done because the upper and lower radiator hoses had to be replaced. Pin hole leaks -- maybe age, probably due to the oil. Problem is, transmission fluid is fine. Except for the oil in the coolant, all the fluids look clean and at the appropriate level. What else besides the transmission fluid hose should I have checked? Thanks!

 

[JMarkert]

Very mysterious, but I guess it's good that your motor and transmission oil are OK.

Here's another potentially useless story. My old car, a manual c900 had a whole INCH of oil floating in the coolant reservoir when I bought it. I suspected the head gasket, but it ran very nicely and passed a compression test perfectly. I figured that since there was so much oil there maybe someone made a big mistake topping up the oil.

I cleaned it out and did several flushes, and changed a bunch of hoses. However there was always a little oil in the coolant reservoir. I just figured that there were lots of places for oil to hide in the engine, hoses, radiator and heater. The car ran nicely for the 15K miles I owned it.

So the moral of the story is MAYBE it isn't that big a deal. Maybe it was a minor head leak and the retorque fixed it but there is still oil in the system and will be forever.

You might consider doing several more flushes and fills with just water now that the danger of freezing is almost past. Maybe fill and drain it once a day for a few days, driving it in between. Kind of a pain to do, but it might make your hoses last longer. Once the water stays clean, then you can add antifreeze. I know running just water isn't great, but I would think that a few days in cool spring weather won't do any harm.

EDIT Oh, and just maybe a little mild detergent would speed things along? I dunno, maybe this would be very bad for the metal too. But it is something to consider. The big problem here is that it's hard to get all the fluid out, there's a lot of dead space.

 

[PMI]

More information pls?

By pressure test, do you mean the cooling system was pessurized using a pump and adapter at the reservoir?

This would only show a significant coolant leak. A slow oil leak into the cooling system that only happens when the engine is running at temperature might not show up on a pressure test, oil can slowly insinute itself into cracks coolant will not penetrate.

How many times was the coolant flushed AFTER the retorque?

If the bolts were loose, the retorqe may have fixed the problem, a pressure test would show nothing, but some oil might be left in the cooling system. One flush will not get it out if it's been there a while. A couple flushes using a professional pump and some cleaner might do it, but maybe not even that. The oil will be on all the hose surfaces, the thermostat, inside the throttle body cooling lines, and the water pump. If the oil has been there for a while, flushing with water alone won't do much either (seen it tried on a different car).

 

[ragtopcav]

Unlikely longshot...


A porous casting.

The cylinder head is cast, aluminium is a notorious 'aspirational' metal when molten, if it is not handled correctly as it is cast then there can be sufficient 'micro porosity' to allow water and oil to mix through the voids in the casting manifesting as that yukky mayo' sludge in places.

Like I said, unlikely but it is not unknown.

 

[Slaab4life]

if it is not handled correctly as it is cast then there can be sufficient 'micro porosity' to allow water and oil to mix through the voids in the casting manifesting as that yukky mayo' sludge in places.

Hmmm, a tiny bit off topic, but is that what was up with VW engines? When I was younger and driving my mother's brand new leased Jetta ('98), the whole time of the lease it had the mayo oil, then my friend who had an earlier model year ('94 or '95) it too always had the mayo despite no headgasket trouble. Your explanation of the casting process is the best guess that I've heard as to why this occurred on two good Jettas.

 

[CasualBloke]

Hmmm, a tiny bit off topic, but is that what was up with VW engines? When I was younger and driving my mother's brand new leased Jetta ('98), the whole time of the lease it had the mayo oil, then my friend who had an earlier model year ('94 or '95) it too always had the mayo despite no headgasket trouble. Your explanation of the casting process is the best guess that I've heard as to why this occurred on two good Jettas.

Or maybe condensation through short trips and an insufficiently warm engine. I used to have a Corvair (air-cooled) that would develop the "mayo" during winter. Clearly there was no possibility that it was due to leaking coolant!

-Brian

 

[brigham115]

As far as I can tell, he did a pressure test (adapter on the reservoir) on the cooling system to see if any coolant was leaking into the cylinders. Which it wasn't. All the flushes were prior to the most recent visit with retorquing head bolts and pressure test. The oil looks good -- no sludge, no mayo. The transmission fluid looks fine. There is no sweet smell and no white cloud when we start the car and the coolant isn't noticeably disappearing. We drive this car 2000 miles each month, commuting at high speed for 40 miles and in stop and go traffic for the 40 miles home. We love this car but would feel better if we were sure it is ok.

 

[mike saunders]

Uh...that car's a absolute death trap. I'd feel horrible about you commuting that far in it, so -- and it's a deep sacrifice on my part -- I'll take it off your hands for $500?

Seriously...If the pressure's ok, the head bolts were retorqued, there's no smoking or chattering, and everything else checks out...Then you better like the color of that car, 'cause you'll be seeing it in your driveway for years. :cheesy:

I wouldn't worry about it at all. Just monitor the fluids every week or so (it sounds as if you do this already), and give it a lovely meal of high-quality synthetic oil every 5,000 miles...

 

[earthworm]

Uh...that car's a absolute death trap. I'd feel horrible about you commuting that far in it, so -- and it's a deep sacrifice on my part -- I'll take it off your hands for $500?

Seriously...If the pressure's OK, the head bolts were retorqued, there's no smoking or chattering, and everything else checks out...Then you better like the color of that car, 'cause you'll be seeing it in your driveway for years. :cheesy:

I wouldn't worry about it at all. Just monitor the fluids every week or so (it sounds as if you do this already), and give it a lovely meal of high-quality synthetic oil every 5,000 miles...

The best possible advice.
BTW, it has been said that the new Mercedes anti-freeze is the best deterrent against head gasket problems.

Also, I have heard that GM recommends their, or some other brand, of a coolant system sealer, maybe this seals the porous aluminum heads.

I use a anti-leak(but am not crazy about it), in the '96 which WAS losing an ounce per 500 miles, maybe at the heater hose connection..