Hello all!

I searched the forum and can't find anyone that had the same issue as me.... so sorry if this is a repeat post.

My 97 A4 1.8T started overheating... took it to the shop and they said the water pump was blown (common problem in B5's i guess). So they fixed it... and the car no longer overheats. However, the heat no longer works. I can set it on HI and it blows COLD. Which really sucks with the rain and cold here in the Northwest. Cause the defroster doesn't work very well with cold air blowing.

I would take it back to the shop however that shop has closed (damn economy). What do you think could be causing the heat to no longer work after a water pump change.

The running temp of the car is perfect (just below the halfway mark) and it heats up in a normal ammount of time. However no matter how fast I'm going, how high (or low) the RPMs are, or how long I drive... the heater blows COLD COLD air.

Any ideas? Could air in the cooling system cause this?

Any ideas are greatly appreciated.

Thanks!

 

Check to make sure its been purged of air properly. Then check your heater core hoses. With my situation, the thermostat was not opening and the coolant couldn't flow through the radiator, but I still had awesome heat. The only thing I can think of that would cause this is a trapped air bubble. Here's how to burp the system:

Remove the corrugated plastic thingy by the battery. (Slides down) The two hoses are heater core hoses. I believe its the right one with the small pinhole. Remove the clamp and wiggle it back just enough so that the pinhole is off the post, but the hose is still attached. Take more coolant/water mix and begin to add it to the coolant reservoir. I had to unbolt the reservoir and lift it up high, which pushed coolant through the overflow into the top of the radiator. Squeeze/wiggle hoses to help free air bubbles. You're doing this all until you see coolant come out of the pinhole in the heater core hose. Then put your finger over the hose and hook hose back up.Check to make sure the reservoir reads in the correct lines. Take it for a spin and include some slow drives up and down hills to move the coolant around and force air out. Recheck the coolant levels when you get back and report on how your heat is doing.

 

Also, you can flush your heater core, it may be gunked up. Write ups on Audiworld.

 

Thanks! This was really handy to get the air out of my heater core. Note to readers: the LEFT hose is the one with the bleeding hole. Also, you don't need to unbolt or unscrew anything to remove the black plastic cover over the hoses. Just pull off the rubber trim piece holding the cover to the outer firewall, and the whole thing will pull off.