I just recently replaced my water pumpback in May due to I had massive amounts of water and coolant leaking from my car. The heads were checked and nothing was warped. The leak stopped for about a month and a half and now the problem is back again. This time, the reservoir will not even hold water at all. With the car completely off, I put the water in the reservoir and whithin a minute, all the water has leaked out. I took it to a master mechanic and he said the water is coming from the back of the block near the heater hose to the firewall. I had all the hoses checked for the radiator, coolant lines and heater hoses. No tears or leaks. He is a master mechanic and does not regularly work on Audi's. He could not tell me what the part was called, so I am inclined to take whatever he says as BS. What could this be? I have been reading a lot about auxillary water pumps, j plugs, and compression rings. Someone please help!
Probably the black cross pipe on the back of the engine that goes between the two heads. Sealed with O rings on either end. One is probably leaking and badly by the sounds of it. $.25 O ring, but absolute PITA to get to.
'99 A4 2.8 Tip Quattro(220k miles and still going strong)
'03 Allroad 2.7t Tip (Gen I with OE style front, Bilstein rear)
Have you checked the rubber hose going from the resevoir to the coolant line in the back of the heads? This hose has braiding over it and that could make it difficult to spot a leak. What about the resevoir itself, as they are known to crack?
Like 4D4 said, if it's that big, it should be pretty easy to locate. I'd unscrew the resevoir, flip it over, look at it, and look at the hoses going to the back of the engine. Then I'd look at the coolant pipe to the back of the heads.
But as 4D4 said, since we can only guess...it could be almost anything.
Just from the common sense angle, my thoughts are leading towards an obvious ruptured hose/fitting. Having said that, it can be difficult at times to find out exact origins of the leak. It is somewhat difficult to find a small leak but, if you are emptying out the tank quickly, things should not be that difficult to trace it. Trace the coolant hoses / route through the diagram and isolate the area. I know, sounds easy typing behind a screen but, that's what really going to help. It's not easy for any of us to pinpoint the leak over the forums as you can understand. Hope you find it quickly.
ʘ˥ Pearl White А6 Ч.2ℓ Quattro
Sport, cold, everything -Nav.
No more OIL or COOLANT leaks! │ T-Belt, Water pump & Valve Covers DONE! │ Trans & Diff Fluid DONE! │ Bearing & Inner Tie-rod Next │ Steering leaks? │ Fuel Banks 1 & 2 Lean issue fixed (finally!) Rebuild Bosch 150 Amp Alternator (save major $$$)