I have a 2001 a6 2.7 with a coolant leak. I jacked the car up to look for the leak. It only leaks when the engine gets up to tempature. I con not see up far enough to fin the starting point of the leak. The coolant runs down the back of the block where the tranny meets and looks like the leak is above the tempature sensor. I tighted that sensor thinking that was it but it was not. I have read about water pump failure in the search. Kinda sounds like that could be my problem. Is there any where to look to know for sure with out taking my manifold off.?

 

The water pump is on the front of the block and is timing belt driven. If the leak is on the back of the engine chances are thats not what it is. What you need to do is get a good flash light and a small mirror to find exactly where the leak is coming from.

 

It is most likely coming from the auxiliary pump or its plastic casing. This part is prone to failure on our cars.
Expansion tank is also known to crack/leak but you;d see that. The way your describe it running toward the back is that auxiliary pump. A little labor to replace

 

Kind of need more info, you should have some pink crust from where it's leaking. Is it drivers or passenger side? It can be as simple as the coolant tank.

 

I had a coolant leak at the rear of the engine that was visibledown the back of the bell-housing and the exhaust. It turned out to be a failing secondary or auxiliarycoolant pump like formulagigi mentioned. It's about an hour job at shop rates and the part was apprx $140. My independent shop did the work at the same time they replaced the clutch.

 

It is not the coolant tank. It is on the driver side. Leaks out some where above what looks live a temputure sensor. then runs by that sensor and down the block where the tranny mounts to the block. I do not what to order a auxillary pump and atempt to install it with out knowing for sure.

 

I still would not rule out the tank. It can run down lines & look like it's coming from one place, but it's coming from some other place.

I would pull up on the overflow drain on the tank & make sure it's not that, first. If it's the sensor back there, it's the afterrun pump sensor, there is just a plastic clip, & O-ring. So all you need is a new clip (if you break the old one) & a $.20 o-ring.

If you remove the engine covers DV's & TBB, you can see the afterrun pump, if it's covered in pink goo, then that is also leaking.

 

Just had a coolant leak. I took it to the dealer cause i have a 100K warranty. They discovered it was the rear aux pump. They ordered the part and will replace it for free. They said its a 4 hr job. I'm so happy.

 

i had a leak and it was only the hose and took it back to the dealer and even though it wasn't under waranty they replaced it all for free since it was leaking when we bought the car. So it might just be simple like that as well....not sure how the hose broke but all is well