Hey guys, I just picked up a 740 turbo on the cheap because there is oil in the coolant reservoir. The transmission fluid is off the stick low, but the remnants on the stick is red and sweet. The engine oil on dipstick is nice and black. The coolant reservoir itself is dark and sludgy and has a milky waxy residue floating on the surface of the water. I used a combustion gas in coolant tester and that came up negative.
Where are the sources of water/oil crossing over on these motors? I thought that it had a radiator oil cooler but it looks like my oil cooler is external and on the drivers side front of the engine compartment.
Turbocharger seal
Head gasket
Would transmission fluid make the coolant red or would it be as described?

Thanks for your time, I am trying to get this thing squared away before it gets too rainy, thats the whole point of buying it, a dry car (my other car is a convertible that I have never had in the pouring rain)

Tomorrow I will do an oil change and drain the coolant, and loop the transmission cooler lines and see whats up. The fact that the transmission fluid is very low is instantly suspect.

 

My bet would be head gasket but I would expect the combustion gas test to come back positive. Does your engine oil look like a milkshake? If it does, I still suspect head gasket.

 

If its an auto box I would suspect the oil cooler in the radiator is leaking.When you mix the transmission fluid with antifreeze you will get a milky brown color. With a head gasket problem you would usually get water in the oil and not oil in the water. If its the rad. then you'll need to replace it and flush the system before refilling. Good luck.

 

Thanks. I suppose I figure that coolant actually wont trump the other systems as when there is a leak in the system it doesn't have the capacity to build pressure. I will flush and loop my lines to verify and then probably have to get a new radiator, as I know it is important to have the oil/water cooler on a transmission.

 

good news everyone! Drained the coolant out and it has oily residue through the whole darn cooling system, it looks like slip or watery clay. I am planning to run dishwashing soap through the cooling system in order to hopefully clean most of it out, as it is very oily and water just goes around it (maybe why the car was starting to run hotter and hotter). However, I wasn't about to throw a potentially fatal mix of soapy water through the cooling system without absolutely knowing that the trans cooler was the issue. Well, I had a eureka moment and took my hand held vacuum pump out to the car. I threw a silicon hose on the tip of it and verified it wasn't leaking by itself by plugging the other end with my porous finger, and it held whatever vacuum I applied. I hose clamped one end to the lower extension on the radiator, past the threads, and put my finger tip on the upper nipple and found I was leaking vacuum at the expected slow rate of a pinhole leak. I just purchased a replacement overflow tank, as I broke the lower hose nipple off last night removing the hose (the nipple was collapsed and cracked) and tomorrow I plan to load the coolant up with a degreaser and run the motor till it is nice and warm. I was thinking of removing the thermostat in order to get the cleaner through the block pronto, but I am not sure. As I work at a dealership with plenty of more knowledgeable mechanics I will run it by them. Anyway, if I can get this crap out of the block and lines I plan to replace the radiator, and unfortunately every single rubber hose on the car because they've sat for 2 years with this oily mix coating their every wall, they're swollen and shot. The intercooler hoses are coated in oil too so, fudge it, might as well perform a nice underhood refresh.

 

the transmission cooler pipes are no longer available as new parts, so any repairs there will have to be fabricated... I've heard of people using steel brake line tubing, also a mix of oil-safe rubber hoses and steel lines, with clamps.

 

I'm under the impression that the transmission cooler inside the radiator is leaking due to all of the above. I will be replacing the radiator after I get all the gunk out of the cooling system. I want to minimize the chance of leftover gunk getting into new parts, as I will be replacing all the radiator and other coolant hoses. Looking forward to doing the heater hoses.