I need some help with my '98 A4 2.8. It's about 13 degrees outside by me and my Audi is blowing cold air when the heat is on. If I have it on the very lowest setting, I get a slight amount of heat, but barely any. I had one guy look at it. He said a 'heater core flush' may help. I really can't afford to replace both hoses, so would prefer this option. Does anyone know if this helps, and what fluid it's best to flush it with?

Thanks for your help.

 

Ive heard of guys dumping in CLR, which is a scale remover made to clean hard water and iron stains off of plumbing fixtures. You need to flush it out good though. In my experience the lack of heat is more commonly due to air trapped in the core itself. If you loosen the clamp on the passengers side hose there will be a small bleeder hole. This is there to help purge air out of the heater core so coolant can flow through. If you've had your cooling system opened recently this is more than likely your problem.

 

Before you start putting chemicals into the coolant system, id answer this first.

Any cooling system work recently? If no, I'd rule out air bubbles.

When the engine is warmed up, Are both upper and lower radiator hoses are equally warm - Rules out a possible thermostat

If there is a little heat come through the vents it could be the temp door actuator not opening all the way.

Is it the same if you cycle the modes from dash, defrost and floor?

Could be a few other things but i dont want you to go crazy...yet