OIL IN COOLANT???? HOW???

[diesel1995]

I have a 1995 K2500HD 6.5 TD truck that has a very strange problem. It seems that oil is somehow getting into the cooling system, and floating up into the resevoir tank. Keep in mind this truck uses no coolant, and it does not contaminate the oil with coolant. It's a very strange problem, and in getting mixed opinions.

Any Ideas?
Jake

1995 K2500HD 6.5L L65, 4L80E
4.10 Gears, B&M Shift Kit, GM-8 Turbo, BD Performance Chip, Homemade Boost Controller, K&N Filter, Dual Trans Coolers, Dual 3 Inch Exhaust.

1/4 Mile - 17.2 at 79 MPH

Mods to come:

Mandrel Downpipe
Cooling Upgrades
Intercooler???

[JeepSJ]

I have never seen anything good that caused oil and water to mix. It is possible for oil to get into the water without water getting into the oil if the problem is somewhere in the pressurized oil passages - the oil is at a higher pressure than the water. If you have an oil cooler in your radiator, that is the most likely place to start looking.

Also, are you sure it is engine oil and not ATF? If it is ATF, look in the same place - the cooler in your radiator.

[diesel1995]

Anybody know any REAL good ways to find out whether its oil or ATF? Its easy enough to get a sample of it, but being as black as it is and probably laced with coolant, its not discernable as to what it is by smell.

Jake

[britannic]

Black says it's got soot in it and therefore it's probably engine oil. ATF is usually red and is unlikely to turn black unless there's something wrong with the transmission.

[ucdavis]

Ditto on black is probably crankcase oil (possible ATF could react w/coolant to turn black, but that's a stretch).
If I had this condition, I'd get an oil analysis kit & get the oil checked for coolant.
The likely thing is a bad head gasket or head crack; could be a block crack (personally haven't heard of that for your condition, but others may have).
I don't know the EGR system too well, so maybe someone else can hypothecate whether that could also be a source (it recirculates crankcase oil).