Babbabooey

2009 A6 coolant level keeps dropping. Neither my mechanic nor Audi dealership can find a leak. Water pump was replaced right before I bought it. Had it for a week before coolant level dropped. Initial diagnosis was air or burbing. Sometimes it's days at same level, then it will drop an inch or two suddenly. Keeps happening. No indication of dried pink gunk anywhere. Thoughts?

KHedges

I'm not an expert, but the two obvious reasons that your oil and water would end up together are a blown head gasket or a failure in the oil cooler. If the inside parts routing coolant through the oil cooler failed, that could cause it too. I found this out while researching the oil leak from the oil cooler, which is likely to be a cheap little gasket and hopefully not a bad job to combine with an oil change I'm due for anyway.


The oil cooler is the thing you screw the oil filter onto. It's super easy to access, and ramps would do the job. This is right behind the radiator on the driver's side.

Here's a close-up of the coolant lines going into the oil cooler.
You can see the greasy mess on those coolant lines from the oil leak. I'll probably replace those with heater hose while I have the oil cooler off. After what I saw behind the engine, I don't want to risk them softening and failing on the road.

Sallad

Wow old thread, and the OP never said anything about mixing oil and coolant.

...but to add to this post. I have and still have this problem once and a while as well. Ive replaced one of the coolant sensor O rings and this cleared up the "visible" signs of dried coolant.

I still have intermittent coolant loss, I can go over a month and no change. I suspect more O rings somewhere else need replacing.

Like this entire car... replacing gaskets or Orings. sigh

KHedges

I meant to reply to a different post. I'm having difficulty navigating on the mobile site. I suspect I accidentally selected one of the "related posts".