Is there any kind of test short of sending a sample to Blackstone or the like to verify if there is actually fuel in my degas bottle as opposed to oil residue from bad oil cooler O-rings?

 

Try dyed offroad diesel and distilled water. The distilled water should remain clear, but if it develops a red tinge at the edges of the water level in the degas bottle, I'd suspect that the dyed off road diesel is present.

That was my indicator.

Wasn't sure at first, coolant smelled funny. When I continued towing heavy, I noticed the red tinge of diesel contamination.

Given, it's a farm vehicle and using off-road diesel on highways is not advocated. I feel that I must state the fact that it's illegal.

 

You can see diesel in your coolant, they separate.




This was a bad cup on the #1 cylinder after a 400 mile drive. After replacing all 8 cups, I have 1000 miles on the truck with no diesel in the coolant.

 

It sounds like he sees something just needs to determine whether it's motor oil or diesel fuel.

 

Tools needed:

• A form of bright light.
• Eyeball(s).
• Corrective lens(es) as needed.

Combustion gasses




Fuel and oil



Sample drawn from top of degas bottle




This is one of those issues where if you have it, it ain't subtle.

 

Thanks to the replies. I think what I am seeing is left over oil residue from an earlier oil cooler O-ring problem. I flushed the system several time but never did any "cleaners". It does not smell of diesel and there is a slight sludege on the degas cap and the surface of the coolant, but this has not changed in over a year. Coolant level has remained unchanged.

 

Diesel will destroy the rubber gasket on the thermostat as well as make your radiator hoses very soft.

If you're diesel mix in your coolant lines, you'll end up with a lot of hoses needing to be replaced and your degas bottle will overflow from the excessive fluid

keep a watch on it! Post pics too.

 

Thanks,
As I mentioned I don't think that it is diesel. I need to remove the degas bottle and clean it to verify what is in there. No change in coolant level for over two years.