Just bought a 97 A4 quattro 2.8L V6. I live in Indiana so it is cold this time of year. When I bought the car it did not run. Had it towed to my mechanic and he slapped a new temp. Sensor on it and it runs well. Only problem is it won’t heat up. On the highway the engine is reading just below 1/4. In town and while idle it gets up to where it should be but I still get no heat.

The mechanic changed the coolant when he worked on it but said he could not find the bleeder. I went back and found the bleed hole after the fact but it seemed that no air was coming out.

At this point I am ready to drain the coolant, flush out the system with water, flush out the heater core and replace the thermostat.

Does anyone have any suggestions that could save me time and effort or think that it is something else entirely?

Thanks,

Ty

 

Based on your description it sounds like you have more than one issue. The fact that the car looses temperature when moving sounds like a stuck thermostat. When the car is up to temp (in your case, at idle) you should be getting heat so its either an internal problem (e.g. interior temp sensor or blend door, you could scan for HVAC code using a VAG COM or by following the procedure http://www.audiworld.com/tech/int.html here click the link regarding the climate control) or the more likely problem of a plugged heater core. I think you are on a perfect track for now, replace the t-stat and since your going to lose coolant any way, flush er out. Good luck!

 

There are multiple places to bleed out the air. I have a small coolant leak and I know from experience that it seems like most of the air collects at the heater core. Bleed the air there and see if it makes a difference.

 

anyone got pics of where the bleeders are located at? Thanks

 

Ok, So I completely flushed out the coolant system yesterday as well as the heater core. I ran hot water through the heater core and actually got out a lot of grit and grime (all small specks of grime but after about 4 to 5 times on each side it added up). After filling back up with coolant and bleeding I started the car up and it started to over heat. turned the car off and bleed it again. This time a bunch of air came out and all of the sudden I had hot air and the engine temp reading was in the vertical position where it should be. Thought I had fixed it but came out today and while the car heats up some of the time, it does not heat up all the way every time. I am happier because I'm getting warm air when the car is moving but when idling it is luke warm. Any ideas? Im going to try and bleed it again and see if that helps. I haven't replaced the thermostat yet. I would like to save that as a last resort seeing that it's a very involved job.

Thanks,

Ty

P.S. I'll post a pic of the bleeder hole leading to the heater core later today

 

There are three. One at the heater core hose, one by the coil packs on the front of the engine, and one under the coolant reservoir on the water pipe on the back of the engine. I usually only do the first two. The process is explained here and here at step 14. Some people bleed the system by removing the coolant reservoir cap, turning the heat to max, and running the car until air bubbles stop showing up at the reservoir. I've never tried it that way though.