PathMD221b

So I just had the water pump replaced and the valve cover gasket, but I still find myself having to add coolant to my car. It was my understanding that the water pump was faulty and was causing the coolant leak. Was it not the water pump after all, and there is another source for the coolant leak?

DanTheC7Man

So it's normal to have to add coolant a few times when it's been drained and refilled as air bubbles/pockets will make their way out of the system during the first few drives of the car. This is especially true if the cooling system was not vacuum-filled.

If it really seems like a coolant leak though, then there are many possible leak sources and it's hard to determine without physically looking at the car. I would first check to see if you noticed any coolant on the ground or not. If there is, then you should be able to find the leak by looking around in the engine bay. Look at the radiator and reservoir and follow the coolant lines from there.

If there isn't coolant visible on the ground or in the engine bay, that means the leak is internal or under the supercharger (where you can't see). I had the issue of leaking intercooler cores, which you can only see once you take the supercharger off and remove the intercoolers from it. These intercoolers tend to fail over time as they experience many heat cycles. Usually people replace the intercooler cores but since the leak wasn't too bad for me, I used radiator "stop leak" and that seems to have fixed it. I've put over 10,000 miles on the car since with no more leaks.

That's just one possible leak though. It could also be coolant pipes or connections under the supercharger, PCV housing failure, head gasket failure, etc.

PathMD221b

Thank you for your insight. It is much appreciated.

PathMD221b

Yes, V6 non diesel

PathMD221b

So the loss of coolant is getting worse. I am finding I am driving less miles and have to more frequently add more coolant each time. When I added coolant last night, I noticed significant wetness at the bottom of the engine bay. Any thoughts on the most likely culprit of the leak? Did I really need a new water pump?

kronikfumes

forgot to mention after getting the water pump replaced on mine that I too noticed my coolant level dropping afterwards. If I remember right there was coolant at the bottom of the engine bay like you are noticing. Turned out that the shop that did the work had not put the drain cap on properly and it was leaking from there, shop fixed it no charge. I would contact the shop that did your work if you can and see if they can inspect their work.

PathMD221b

I am bringing the car back to the shop where the work was done…maybe this is the answer. Thank you .

PathMD221b

Ok, so the mechanic re-examined the car and found the problem to be a leak in the thermostat housing unit. He is going to fix this and then I’ll be trading in the car or selling it.

kelisko

Sorry about your troubles. It is likely a cracked top coolant pipe. It is made of plastic on your generation of engine whereas it used to be made of some metallic material. They eventually changed it to aluminum in the next CREC engine but the new engine itself as a whole (mine) is worse than the outgoing one (yours). Trade it in instead of selling it. At least you won't be selling the junk to a poor and unlucky next owner yourself. Let Audi deal with their junk. A Lexus for sure will be much more reliable and a BMW may also be, according to recent studies where Audi occupy the last spots.

DanTheC7Man

Ah dang. Sad to hear you’ll be getting rid of the car. It’s a great car when everything works fine but unfortunately issues are somewhat common and tend to cost a few thousand dollars if you’re not doing it yourself, so I understand. You probably have no interest at this point but replacing the PCV housing would be a great “while you’re in there” when replacing the thermostat, since they both sit under the supercharger as I mentioned before. I’m thinking it’s probably it’s the cause of your oil consumption issue, but there’s no way to be 100% sure especially since you said you don’t hear any whistling sound. In that case, it might make more financial sense to leave the old one and sell/trade it as is.