Coolant in oil help

A6 All/ S6 All
#1

Hello,

My S6 has been sitting in my driveway stationnary (has maybe been started 2-3 times) since end of november while chasing an issue that ended being just a f*cking blown fuse SMH.

Ive noticed during this chase that my oil got milky, and my coolant level dropped to the point where my car warns me when I start accessory even tho I only started the car a couple of times.

Ive seen that the most probable cause is the oil cooler? I dont think there is oil in my coolant, just coolant in my oil, so is there a way to check if its the cooler and not the timing cover o-rings that failed?

Thanks

#2

I pressure tested the coolant side of mine while I had the engine out to make sure it held pressure.

#3

I think there would be oil in the coolant too if it was the cooler with the pressure differences, I guess if the car hasn’t run as much the oil in coolant wouldn’t be as noticeable. The only way I can think of to know for sure is to pull it and test. Maybe do a pressure test on the coolant and listen for any leaks?

Also my leak was the radiator. Did the oil cooler o rings while it was off too, that was aggravating and couldn’t even get the hoses off of it.IMG_20260228_181223338_HDR

#4

Well Im just gonna replace the whole cooler and seals and pray that thats what it was. If not, engine needs to be pulled for the timing cover o-rings. Either way, surprisingly, the oil cooler is pretty cheap for an important s6 part :+1:

After its replaced, im going to do the oil change, and check regularly the dipstick for milky oil

#5

That makes the assertion that the bulk of the contamination is occurring while the engine is running.

For the majority of us, the engine is off up to an order of magnitude longer than it is on. During this “off” time, the cooling system remains pressurized while the oil pressure bleeds off quickly once the pump shuts off. If I am not mistaken, the oil cooler does not even start to see pressurized oil until after the oil reaches normal operating temperature.

#6

So that means it isnt the oil cooler or that it might be the oil cooler, but since it doesnt pressurize I dont see oil into the coolant?