Oil in coolant

[Medgas24]

Has anyone else experienced oil in their coolant? Showed up to work and saw this

 

[bigdodge]

Has anyone else experienced oil in their coolant? Showed up to work and saw this

Go to dealer, asap

 

[mikeru82]

When oil and coolant mix you usually get something that looks like a chocolate milkshake. That looks more like pure oil. Who serviced this truck last and when? Did someone dump oil into the expansion tank?

 

[Darksteel165]

I know people have mistaken putting windshield washer fluid in the right place, but never saw someone put oil in the wrong hole.

 

[Rick3478]

When oil and coolant mix you usually get something that looks like a chocolate milkshake. That looks more like pure oil. Who serviced this truck last and when? Did someone dump oil into the expansion tank?

Chocolate mousse happens when you get antifreeze in the crankcase, where the combination gets thoroughly beaten by crank and rods. Whoever said oil and water don't mix has never seen this.

But oil in the coolant doesn't get beaten that much, and oil being lighter than water, will separate and float to the top in the expansion tank.

There have been reports of problems with the intercooler in the lower radiator hose, made from thin metal tubing and some of the welds may not be up to the task. In operation, oil is at higher pressure than the coolant, so if the leak is small you can get a slow migration of oil from crankcase to expansion tank and out the overflow.

That's my guess. Check the oil level to verify.

 

[mikeru82]

Chocolate mousse happens when you get antifreeze in the crankcase, where the combination gets thoroughly beaten by crank and rods. Whoever said oil and water don't mix has never seen this.

But oil in the coolant doesn't get beaten that much, and oil being lighter than water, will separate and float to the top in the expansion tank.

There have been reports of problems with the intercooler in the lower radiator hose, made from thin metal tubing and some of the welds may not be up to the task. In operation, oil is at higher pressure than the coolant, so if the leak is small you can get a slow migration of oil from crankcase to expansion tank and out the overflow.

That's my guess. Check the oil level to verify.

How is going through the water pump not beating it up?

 

[Medgas24]

So I took it to a shop had to add 5 quarts to it to drive 27 miles I had it parked there for 5 minutes see below picture !
They found my transmission cooler broken leaking into the radiator as well

 

[Medgas24]

Chocolate mousse happens when you get antifreeze in the crankcase, where the combination gets thoroughly beaten by crank and rods. Whoever said oil and water don't mix has never seen this.

But oil in the coolant doesn't get beaten that much, and oil being lighter than water, will separate and float to the top in the expansion tank.

There have been reports of problems with the intercooler in the lower radiator hose, made from thin metal tubing and some of the welds may not be up to the task. In operation, oil is at higher pressure than the coolant, so if the leak is small you can get a slow migration of oil from crankcase to expansion tank and out the overflow.

That's my guess. Check the oil level to verify.

There’s also a mechanic on tik tok that explains this pretty well !

 

[HSKR R/T]

How is going through the water pump not beating it up?

Once it gets into the overflow tank it has time to settle and separate back out.

 

[Rick3478]

How is going through the water pump not beating it up?

Centrifugal pumps and turbines, for the most part are engineered for laminar flow, and don't really do much mixing. In fact, mixing is not desired as it saps power. Fish nurseries pump fingerlings around with very low mortality.

The oiling system is very different. Lubricant gets squeezed through bearings under high pressure, temperature, and shear, sprayed on cylinder walls, impacted by crank and rods, etc.

I don't have any numbers to put on it, but would imagine at least an order of magnitude difference in "mixing".

 

[Rick3478]

So I took it to a shop had to add 5 quarts to it to drive 27 miles I had it parked there for 5 minutes see below picture !
They found my transmission cooler broken leaking into the radiator as well

Transmission too? Yikes!

 

[SD Rebel]

Based on how it looks, it is likely the oil cooler leaking, which is way better than the head gasket leaking.

 

[mikeru82]

Based on how it looks, it is likely the oil cooler leaking, which is way better than the head gasket leaking.

How is that better? Lots of transmissions in Nissan Xterra's and Pathfinders had to be replaced because of this exact thing happening. Transmission fluid lines inside the radiator allowing trans fluid and coolant to be exchanged. If there's transmission fluid in the cooling system there will probably be coolant in the transmission. Search on "strawberry milkshake of death".

 

[SD Rebel]

How is that better? Lots of transmissions in Nissan Xterra's and Pathfinders had to be replaced because of this exact thing happening. Transmission fluid lines inside the radiator allowing trans fluid and coolant to be exchanged. If there's transmission fluid in the cooling system there will probably be coolant in the transmission. Search on "strawberry milkshake of death".

Not sure about all that, I was talking about people finding small amounts of oil in their expansion tanks, which was traced to a leaking oil cooler, which seemed a common and simple fix for 2019-2021 older versions of that cooler.

I was assuming that was an engine oil cooler, not a transmission cooler, so I'm probably mixed up here.

 

[HSKR R/T]

How is that better? Lots of transmissions in Nissan Xterra's and Pathfinders had to be replaced because of this exact thing happening. Transmission fluid lines inside the radiator allowing trans fluid and coolant to be exchanged. If there's transmission fluid in the cooling system there will probably be coolant in the transmission. Search on "strawberry milkshake of death".

If it's the engine oil cooler, it is better, as the oil pressure would force the oil into the coolant, and not the other way around. Transmission cooler and fluid isn't under the same pressure.

 

[mikeru82]

If it's the engine oil cooler, it is better, as the oil pressure would force the oil into the coolant, and not the other way around. Transmission cooler and fluid isn't under the same pressure.

The OP said it was determined to be trans fluid in post #7. The transmission lines are leaking into the radiator.

When SD mentioned oil cooler I was thinking he meant transmission oil cooler since the OP had said what it is by the time SD made that post. Just a misunderstanding.

 

[HSKR R/T]

The OP said it was determined to be trans fluid in post #7. The transmission lines are leaking into the radiator.

When SD mentioned oil cooler I was thinking he meant transmission oil cooler since the OP had said what it is by the time SD made that post. Just a misunderstanding.

He said "as well". Considering he had to add engine oil, Id say the engine oil cooler is leaking I to coolant. The drop on ground might be from trans cooler lines, and not necessarily mixing with coolant in the radiator

 

[SD Rebel]

The OP said it was determined to be trans fluid in post #7. The transmission lines are leaking into the radiator.

When SD mentioned oil cooler I was thinking he meant transmission oil cooler since the OP had said what it is by the time SD made that post. Just a misunderstanding.

It's my bad, I mixed up what the OP was saying.

 

[SD Rebel]

He said "as well". Considering he had to add engine oil, Id say the engine oil cooler is leaking I to coolant. The drop on ground might be from trans cooler lines, and not necessarily mixing with coolant in the radiator

Good point, it could be both, though seems interesting they are happening at the same time.

 

[mikeru82]

He said "as well". Considering he had to add engine oil, Id say the engine oil cooler is leaking I to coolant. The drop on ground might be from trans cooler lines, and not necessarily mixing with coolant in the radiator

He didn't specify what kind of fluid he added 5 quarts of. You assume oil, I assumed trans fluid. "As well" when taken in context could mean more than one thing. I took to mean they found trans fluid is leaking into the radiator, as well as what spilled onto the ground. Fun with English.