Hey guys. New to the forum so I am prowling for relevant info. I just got a 2002 A6 3.0 auto with 77k miles a few days ago. I have noticed that it takes time for the heat to start coming out even though the car warms up. Should I also be considering the problem you are describing here?
Thx
Ck

 

I had all the symptoms reported here spread over the last 18 months, I had a new heater core fitted around 15 months ago and all was well then started to loose heat again recently, I went to audi and they said I needed a new heater core again...

The problem is that the heater core on these cars acts like a filter, the core tubes are so fine they block quickly, a friend of mine who works on these vw/audi engines believes trapped air in the system causes rust in the engine that makes fine flakes that block the core.

I didn't want to fit a new core, I flushed the hell out of the core instead: got some 3/4 clear tubing, attached to the two ends of the core (so I could see the crap coming out), flushed with the garden hose in both directions to loosen the crap, then filled with CLR and left for 3 hours, flushed again both directions - more crap came out.

Filled the core directly with new coolant/water, refitted the two pipes, ran the engine to operating temp, removed the top core hose, revved engine until coolant came out. Let engine cool a little then burped the cap. Started the engine again, then pulled the top hose again until scalding water shot out of the bleed hole. Drove the car hard for 30 minutes up hills. Been perfect for 6 weeks now.

Tip: Flush that core rather than throw money away!

 

ive been saying that since day one. Too many people like to spend money i guess. Go figures?

 

he had heat for 6 weeks... I will bet money that in 6 months he will be back to no heat... I have flushed my new heater core about every month this winter just to be back where I started.

Here is a hint on how to fix the problem once and forever... Get the auxiliary water pump out of the passats 3.0 engines... the part number is 078 121 601
Install the water pump in the hose which takes coolant to the heater core. Then simply use a relay to build a harness to power the pump only when the engine is running... trust me... with the pump installed the temperature on the dash gauge is barely at 1/4 and there is HEAT as any other normal car... never again struggle in a car which is great in snow but you have to dress like a snowmobile man to ride in it... Install the axillary pump and move on with your life. 99% of all other VW/Audi products have those pumps... why the B6 1.8T never got it is out of my knowledge, may be they followed the the same old German engineering rule: "give less, charge more". The oem water pump is simply not powerful enough to feed the spaghetti soup of coolant hoses and actually have some power to feed the heater core after that considering how horribly the heater core location is set and the way the system pushes coolant to it...

 

...funny you should say that, when I did my heater core flush, I had bought a bosch auxiliary pump ready to install if my flush didn't work! But, the flush was so successful I didn't bother fitting it. Maybe you are right - but I am ready to fit it if it does fail my friend

I even have a photo of the pump running to test it - with my clear pipes attached. I will try and find it and post it later.

 

well i fliushed my heater core two years ago and i still have heat without having to replace any other parts. . .

 

you have to define heat... mine did have heat but it was just enough to defrost my windshield and that's it... now I have a constant flow of heat in the range of 200+ degrees out of my vents.

 

well if you dont believe me i can take my handheld temp gauge and snap a pic. Im pretty sure its really hot but what do i know i just ride in my car every day.....