Oil in coolant

[Ehahn84]

So a few weeks ago I noticed a few drops of what I thought could've been oil in my coolant reservoir tank when cleaning the engine compartment. I feared the worst and took it to my mechanic to check for any HG issues. They did a cooling system pressure test, tested compression on each cylinder, and did some sort of gas chemical test and couldn't find anything pointing to a bad HG. So I have started hunting myself. My valve cover gasket leaks like a butch. Could it be that, somehow? My mechanic told me I should look at the oil cooler on the driver side of the block as he believes the o-rings and valve in there need to be serviced every so often and could lead to cross contamination of oil and coolant.

Like I said..no issues whatsoever that indicate a blown HG. What could it be?

 

[jgue467]

I've never heard of the o-rings in engine oil cooler needing regular servicing, if ever.

Despite that I don't know what else would lead to your issues. :cowboy:

 

[RS Dude]

I had to replace the oring and seal on the oil cooler because they were leaking. There is no way for the oil and coolant to mix even if the o-ring leaks, so you can rule the oil cooler out.

 

[Ehahn84]

Well crap. I was gonna redo the oil cooler and hope that was the culprit.

 

[LittleCaesar]

Then get the mechanic to perform a leak down test. He could also inject some dye into the coolant to see where it is going, like what is done in AC testing.

Got a pic of the overflow? What does the underneath of the radiator cap look like?

 

[Ehahn84]

Then get the mechanic to perform a leak down test. He could also inject some dye into the coolant to see where it is going, like what is done in AC testing.

Got a pic of the overflow? What does the underneath of the radiator cap look like?

Everything is clean as a whistle. No fluid loss at all of any kind.

 

[JRZEE2000TR4LTD]

Could it be tranny fluid?

 

[Rwhockey29]

Could it be tranny fluid?

second this. are you still using the stock radiator/tranny cooler combo? its possible its not oil, and its tranny fluid.

 

[Ehahn84]

second this. are you still using the stock radiator/tranny cooler combo? its possible its not oil, and its tranny fluid.

It's a new (4K miles) denso radiator.

 

[JBurt]

Got any pics? Could just be old crap in your cooling system. Did you flush it when you replaced the radiator?

 

[LittleCaesar]

Like [MENTION=84643]JBurt[/MENTION] said, flush the cooling system and see if the oil, or what looks like oil, reappears.

 

[mtbtim]

Could be just a simple case of cross-contamination from a dirty funnel. Any chance you topped off your coolant reservoir recently with a funnel you also use for oil? If you take your rig to a shop for service, did they mention anything about adding coolant?

There's no way leaking valve cover gaskets could contaminate the coolant. But, if you want to take care of those leaking valve covers, here's a video you can use to tackle the job yourself.

<iframe width="560" height="315" src="https://www.youtube.com/embed/N5fAXAuGozI" frameborder="0" allowfullscreen></iframe>

 

[Ehahn84]

Got any pics? Could just be old crap in your cooling system. Did you flush it when you replaced the radiator?

I can't get a good pic with my phone. When I replaced the radiator and all that jazz I did add all new coolant.

 

[Ehahn84]

Could be just a simple case of cross-contamination from a dirty funnel. Any chance you topped off your coolant reservoir recently with a funnel you also use for oil? If you take your rig to a shop for service, did they mention anything about adding coolant?

There's no way leaking valve cover gaskets could contaminate the coolant. But, if you want to take care of those leaking valve covers, here's a video you can use to tackle the job yourself.

<iframe width="560" height="315" src="https://www.youtube.com/embed/N5fAXAuGozI" frameborder="0" allowfullscreen></iframe>

I don't usually take it to a shop unless is something that is above my skills like diagnosing a blown HG. I check all fluids at least weekly and it's never ever been low on coolant. I don't think it could be cross contaminated but who knows. There have been like there little "drops of oil" in the coolant overflow reservoir and there haven't been any more since unnoticed tba month ago.

 

[Ehahn84]

So I just did a test. I got six cups and put coolant in each one of them. I put a little trans fluid, new motor oil, old motor oil, gear oil, brake caliper grease, and black make a gasket shit in each cup. The shit floating in my coolant reservoir looks and feels most like the brake calipers grease. But that shit don't make sense.

 

[GrassFed]

Yeah that surely doesn't make sense. What's nice is that most things in mechanics can be explained; at least partially. If you are getting contaminants in your cooling system, something is not right.

Best case scenario is you are due for a cooling system flush to get all of the gunk out of there.

This might be a good place to start if for no other reason than to get a baseline and go from there.

In short, if I was you, and genuinely concerned with the situation, I would do a flush and basically start over in order to monitor it more accurately- especially given all of the other tests you have done.

Good luck

Matt