Oily film on coolant?

[qstott]

I was checking the coolant in my 1050 last night and noticed some kind of thin film of black oily type substance floating on the top of my coolant in the overflow tank. I thought if water and oil were mixing it would look foamy. What I have seen in automobiles tends to look like chocolate milk when oil and water are mixing. This looks more like soot settled on top of water. The oil looks fine, no problems there. I took the cap off of the radiator and the same substance was floating on top. Just a very thin layer. I had run the tractor for 2 or 3 hours. Could it be some by-product of combustion gases? Any ideas? Thanks!

 

[tb1472000]

Just speculation, but what about some diesel getting in the coolant. Perhaps a head gasket leak into the cooling chamber. Of course, I'd think this would cause some loss of coolant and a loss of power.

 

[qstott]

Thanks for the reply! That's what I was wondering. I recently put a head gasket on it. It was leaking a little coolant to the outside. The head was flat, and so was the top of the block. I don't know how the injection pump works. I wonder if there is some kind of seal between it, and the cooling system.

 

[kwyatt]

Sounds like combustion products, you will also get white smoke out the exhust and excessive bubbling in the raidator while it is running if the leak is very bad.

 

[qstott]

I may have solved the mystery.When I bought the tractor the head gasket was leaking. I had several people suggest putting "stop leak" in it and just run it. I planned to keep the tractor for a while so I decided to change the gasket. I've been told that the thin film looks like the oily film that some "stop leak" products produce. It makes sense that the previous owner poured some in it for a temporary fix. I drained the cooling system and changed the oil after the repair. I'm hoping its just the remnants of the "stop leak".

 

[danbike]

Here is another spin on what you found. IF when the cooling system was drained, you caught the coolant in a pan that AT ANY TIME HELD OIL, when you refilled the cooling system, you might have gotten some oil in the clean coolant.

Not that I ever did that, but the NISSAN dealer in the Highland Park Illinois area did that on a car of mine. I made them flush the cooling system to get the oil residue out.

 

[pat32rf]

Water into the oil produces a milky fluid but oil into water tends to float on top. When the engine is running the oil pres is normally higher than the coolant pres so if the head gasket is bad you could have leakage of black used oil into the rad. When you shut her down, however the oil pres drops quickly but the coolant pres stays up until things cool off. Keep an eye on your dipstick- you don't want antifreeze in the oil!!!