Sudden Coolant Leak A6 2.7t

[btvm92]

I came out this morning to this large puddle under my car


Starting at the front right side of the motor








There are drips all over the front right side of the motor but appear to be coming from further up.
It does not appear to be coming from the lower radiator hose.
















The only thing I can think in that area would be the thermostat or maybe aux water pump? However, I just did a complete timing belt/ water pump/thermostat job about 5 months ago and everything has been fine since. I also took a close look at the aux water pump while in there and did not see anything suspicious.
This all happened overnight, my car is still running at temp, but I noticed that either after running for a bit, OR after the level gets low enough, it will stop leaking.. I came out to the puddle, topped off w water, drove for about an hour and it leaked back down to the same level it was when I first discovered it.


This is w the car off. Is this a dangerous level to be driving on?

[4rings2turbos]

It's fine to drive at that level, but of course you'll want the leak fixed.

Common leak points are the tank (cracks), plastic tstat housing and the aux pump. How good of a look did you get of the aux pump? I'd suggest taking 5 mns once the engine has cooled a bit and taking the y pipe off and seeing if it's wet in there.

Your 01 should have a metal tstat housing and the leak I on the wrong side of the engine for it to be the tank.

[achb5]

I just fixed a coolant leak on my AR, the o-ring to the temp switch failed, basically crumbled apart with age and heat. its in the Passenger side in the coolant hard pipe. Might be worth taking a look.

[4rings2turbos]

I think that's going to be too low to be causing this leak, but you're right. That should be added to the common leak spots.

[btvm92]

It's fine to drive at that level, but of course you'll want the leak fixed.

Common leak points are the tank (cracks), plastic tstat housing and the aux pump. How good of a look did you get of the aux pump? I'd suggest taking 5 mns once the engine has cooled a bit and taking the y pipe off and seeing if it's wet in there.

Your 01 should have a metal tstat housing and the leak I on the wrong side of the engine for it to be the tank.

During timing belt job I had valve covers off and got a fairly good look underneath the intake manifold and it appeared to be dry. Next chance I get I'll get in there and look at it. I do have the metal tstat housing and like I said this came out of nowhere. I'm hoping its a simple hose or something but I'm having trouble finding the source, I read from someone who had a leak in a similar place that it was a plastic elbow from one of the heater core hoses?

I just fixed a coolant leak on my AR, the o-ring to the temp switch failed, basically crumbled apart with age and heat. its in the Passenger side in the coolant hard pipe. Might be worth taking a look.

The sensor located ON the lower radiator hose? That's the first place I looked and everything seems dry down there, the leak appears to be dripping from directly underneath the front right side of the oil pan.

[urAllroad]

The sensor located ON the lower radiator hose? That's the first place I looked and everything seems dry down there, the leak appears to be dripping from directly underneath the front right side of the oil pan.

No, the switch in question is located on the right side of the vehicle (passenger) between the motor and the firewall. There is a coolant crossover pipe connecting the two heads, with sensors plugged into it. To gain access you'd need to take out your intake accordion and perhaps a few other things, at least just for inspection.

[Black-Forest]

Looks to me to be the radiator hose. How did you make out with the diag and repair?