eldoj

My 02 is leaking coolant at a very slow rate. Don't see any obvious signs of a leak underneath. No puddles. But I have to replace a quart or so of coolant about every 3 weeks.

Any guesses as to where its going?

Thanks

defStef

Could be the heater core. This happened to me, similar symptom (adding coolant every 3 weeks). If so that's a costly repair since the dash has to be removed to get at it. The other option is to bypass the heater core so it won't leak. But then, the heat won't work.

S4VP

Auxiliary pump leaks only when the car is running. You will lose coolant over time and not see it under the car. Not enough leaks out to raise the temperature and the pressure decreases the more fluid you lose. If it is the heater core you will smell it inside. To check the first option, look below the intake on the back side and see if anything is wet. Or do a pressure check. If it is the pump, don't bypass it or you could burn up your turbos. Good luck.

Ski05751

Could be the water pump starting to weep. When was your last timing belt service done?

I had a very slow coolant leak also that I couldnt find for almost a year. When I finally got around to doing my timing belt service, I waited till 85K miles, I found the water pump leaking and the coolant was dripping on one of the TB pulleys. The bearings in the pulley were destroyed from the coolant and I had pink slime (semi dried coolant) all over the place. The slime explained why I could not find the leak since the coolant was drying faster then it was leaking so it never left any puddles.

EuroDriver

Its not far from the afterrun pump, Mine had signs of crusted up coolant, Another leak possibility is the coolant expansion tank, if its yellowing and shows signs of cracks, its time for a new one

wilson94t

On my car it was the after run pump that started to leak. It wasn't easy to notice until I really looked for it.

eldoj

After a lot of searching, turns out it is the aux water pump.
In the shop now getting replaced.

Thanks for everyones comments.