Hello
I am new to this forum....I handed down my Audi A4 to my son, last spring i had a new engine put into it,(long story, I blew the engine) car works fine now, however we notice since the engine replacement (no sure they are related) the heat stopped working.....any suggestions on what may have happened or what may need fixed? Thanks! K

 

Since the engine was replaced it makes me think that they didn't hook up the heater hoses correctly. I wonder if they connected them together bypassing the heater core? Another possibility would be a bad thermostat. I take it the fan works fine.

 

Yes, fan works fine, I will have someone take a look at those suggestions before taking it to the dealer.....thank u!

 

The heater core is probably clogged up. Do not take the car to the dealer for they will sell you a new heater core , big $$$$$$$$$$$. The heater cores can be flushed out with CLR.
That's if they did connect the heater hoses with engine replacement.

 

Thank you.....i'd rather not have to take it to a dealer!

 

Heater core really isn't too bad of a job. Part can range from $80-$150 depending on where you get it. There is a fairly current thread in the B6 section that has a DIY link for the job. If you are at all mechanically inclined it isn't too tough.

I tried multiple times to flush mine and eventually just went for it. Have heat now like never before!

Good luck!

 

Thanks for the suggestions!!!

 

If you stand in front of your car and look toward the center of the firewall (with hood open of course), you will see two hoses (maybe underneath a plastic cover) next to battery, take cover off, both hoses should be going IN to the firewall (heater core) and while the car is warmed up, both hoses should be hot. IF they are bypassed then someone put a hose fitting in-between them and they are NOT going INTO the heater core. The one on the right is the IN side to the heater core, the one on the left is the OUT of the heater core. If the hose on the left is a lot cooler than the right when car is at temp and heater fan blasting, heater core is plugged or full of air (not bled right)....

The heater core job on a B6 is a lot easier than on a B5, that's all I have to say. The DIY other's mentioned for the B6 is actually very good and accurate. ON the B5s, I had to take my WHOLE dash out.....on the B6, you are mainly working on the Driver's side...not too bad of a job.

 

I recently did my thermo at my Audi A4 , I had just warm air and now its perfect. my temp gauge was staying down while driving and would only go to normal position when parked up for a period with engine running. my mechanic said if it was water pump the car would over heat.