Coolant in oil, what’s going on?

[KeyTDI]

2012 Jetta Sportwagon with 133k miles.
Did the timing belt, water pump etc at 130k and changed oil.
I sent a sample to blackstone labs and they flagged coolant in oil.
Wondered if I had contaminated the oil with coolant whilst doing the timing belt and water pump.
I had noticed a slight drop in coolant level before but had dismissed it as seasonal fluctuation, and assumed it would be solved when I did the big service and replaced coolant.
Now I just got another low coolant warning my Daughter says, who is borrowing the car.
What’s the deal here?
I read something about oil cooler o rings…. Or could it be a HG?
Any insight or knowledge would be appreciated!

 

[DonL]

I am not a mechanic, nor do I play one on tv. However, I have been around for a few years and first thought is head gasket.

 

[KeyTDI]

Lol.
Yup, I did have that thought as well.
Wonder if it would be covered under the Dieselgate warranty. I bet the engine revisions caused it.

 

[JELLOWSUBMARINE]

Lol.
Yup, I did have that thought as well.
Wonder if it would be covered under the Dieselgate warranty. I bet the engine revisions caused it.

Good point. The heat increase has been fairly well established I would say.

 

[JHands]

Get it replaced under warranty, delete it, throw a 170 on and watch your EGT’s lean more towards the Arctic (best analogy I got, I’m fried)

Good point. The heat increase has been fairly well established I would say.

 

[oilhammer]

I would not let one UOA result matter. And they'll laugh at it for warranty purposes.

 

[MrCypherr]

The chances of a headgasket being covered under the extended warranty are slim. First off, Theres no CEL which is one thing thats needed. Second, they will make you run through hoops by checking/replacing other things before remotely even being close to removing the head.

 

[KeyTDI]

Agreed.
I got the car back from the daughter for a few days while she’s away. Coolant level was down and it took about a liter. I’m not sure if that’s a real number as I don’t know if some or all of that is normal reset of levels after I did the timing belt/water pump service 3k miles ago.
Oil level was perfect, on the full mark, as it was after the service.
There is/was a little doubt in my mind if I’d cross contaminated the oil when I drained the oil last. Id left it dripping into the catch tank, while I did the timing belt and water pump at 130k miles.
Ive been changing the oil every 3-4K miles, so I think I’m going to change the oil today and send another sample out to Blackstone so I’ll know what I’m dealing with.
I did some research and I’m confused about this oil cooler.
is there a water/oil cooler on this model(2012), behind the oil filter, and if so is it prone to leaking within itself or the seals?

 

[needsmoarturbo]

I don't know about if there is an oil cooler on this car but when I had a coolant/oil hear exchanger one fail on my b5 A4 1.8t. when this happened the oil got pushed into the cooling system, not the other way around since the oil pressure is always higher than the cooling system pressure.

Edit. The coolant pressure will be higher than the oil pressure right after the engine is shut off when the engine is at operating temperature, but at any other time it's running the oil pressure will be probably 2-4x the pressure in the cooling system.

 

[MrCypherr]

There is a oil cooler on this car that Ive heard failing where it will start mixing. Never done one but have heard. So take that with a grain of salt.

 

[KeyTDI]

Good info.
I changed the oil and filter yesterday.
The sample will go out to Blackstone today so I know for sure if I have a problem, and will report back.

 

[KeyTDI]

New sample came back with confirmation of coolant in oil.
They said there is no sign of wear related to this and they suggest to watch it.
Opinions?

 

[oilhammer]

Check again in 100k miles.

 

[KeyTDI]

Assume you are joking...

So, the first oil sample they flagged was at 130k, and the comment was this:

"There's some coolant in this sample, evident in the potassium and sodium levels. These levels
don't show much contamination, though; unless the situation gets worse, you probably won't even notice the
coolant level going down. The little bit of contamination doesn't seem to have bothered the engine's wearing
parts. There isn't any more wear metal in this sample than there was in the last one, and that's after running
this oil 50% longer. The trace of fuel doesn't pose a threat. As long as the coolant level isn't dropping, follow
up in ~5,000 miles"

The sample I took at 134k miles, that I just got said this in the comment:

"Unfortunately, this sample still has coolant, and it looks like it's increasing. Potassium improved
a touch, but sodium increased quite a bit and silicon is likely from coolant as well. The good news is that it
doesn't seem to be causing too much harm to moving parts, since wear levels look good here for the
shorter interval, and are at their lowest levels on the page. The minor fuel dilution cleared up this time. The
viscosity is a touch thin, but that's fine. Monitor for coolant loss, and if that checks out sample in another
3,000 miles to see how it looks."

Now, I did change the coolant at 130k and so maybe the new coolant was a more concentrated mix than the old stuff, and that might account for the slight change.

At this point I am unsure what top do...
I could do a coolant test and see if there is any combustion gasses,... but somehow I doubt it.
Is there any other explanation other than the HG?

 

[oilhammer]

Not joking.

Explanation could be a crack in the head, crack in the block, crack in the oil cooler.

Usually an oil cooler failure will result in oil in the coolant, not the other way around, as the oil pressure is far greater than the coolant pressure. So, probably rule that out.

If the engine is running OK, monitor any loss of coolant from the system, that is "disappearing". If it is bad enough to harm the engine (the oil's ability to do its job) it would change the look and consistency of the oil, and the oil level would be increasing. If it is a TINY amount, the oil won't be noticeable. Because it will just boil it away just as it does the rest of the water that ends up in the crankcase vapors due to normal internal combustion engine operation.