Hey Guys,

Need some help, I have a 2000 A6 2.7T with a engine code of p1296 which is a cooling system malfunction. I replaced the CTS but now I think there is air in the system. The temp gauge works sometimes and others it doesn't its very intermittent. I have double and triple checked the connections. Would the air in the system throw the code or would it be something more severe. I was told by a tech to leave the cooling reservoir cap off and rev the engine to about 3000 RPMs until the temp gauge reads properly to purge the system. Ive done this several times now and each time i think it fixed it and then a day later its not working again. While I'm revving the engine I'm noticing a considerable amount of smoke coming from the engine and I think it smells like antifreeze burning but the coolant level doesn't seem to be moving. The only thing I can think of is maybe I have a crack in a cooling line that is releasing fluid while revving and also allowing air back into the system during normal driving conditions. Does anyone have any thoughts on this. Also my heat works fine and the reservoir is pressurized when the engine gets hot. Thanks.

 

Double check the installation if your coolant temperature sensor, the O ring and the plastic clip. Make sure the sensor seats nicely and the plastic clip is in locked position. Checking any small coolant leak there.

 

Only way to check for sure is to run a pressure test on the cooling system. It is basically a vacuum gauge attached where the reservoir cap and pressurizing the system to see if there is a leak. You can buy a commercially available pressure tester, such a made by stant, but you need a VW/Audi adapter to fit on the reservoir.

 

I rechecked it and it is definitely seated properly and not leaking.

 

Just a thought... if the smoke and AF smell are coming from under the intake manifold, it could be your aux cooling pump that has gone. I just changed mine and it was a bitch (about 6 hours and several busted knuckles) but I had the same symptoms and the Aux pump was the culprit.

Forgot to mention - if it is the pump and you are going to change it yourself, be sure to get the intake and exhaust hoses for the pump as well along with worm clamps for all the ends. Mine were welded onto the nipples from the heat and the only way to remove them was to cut the hoses off.