I have recently purchased a used 2006 Audi A4 and LOVE it......however I noticed if I start my vechicle in the COLD mornings, the engine temp or the temp of the air blowing will NOT get warm. If i let the car idle for 20-30min in the morning both engine temp or temperature of the heat will remain cold. As soon as i begin to drive, the warm temperature will begin to blow from the heater, and soon after driving for a consecutive 10min or so the engine temp will go up.....

Im not so concerned about the engine temp, but as the Heat not blowing hot.

Also once the temp of the Air has reached a normal hot, the air will begin to blow cold again if the car is back to a non-moving idle position. (IE stopped at a red light or just stopped in a parking lot)

Odly enough, this happens with my car in the Summer with the AC.....No matter how long i let my car run and "Cool Down" the AC temp will blow HOT until i begin to move the car, wont get cold even if i just rev the car while in parked position.

Used to notice (last summer) that if i accelerated with a hard down-shift the AC would become warm for a few seconds until the car would get back down to normal RPM's

I know both the AC and the Heat are two separate systems, that is why this problem is confusing. I am decent with Domestic Vehicles and am new into the Audi's

Any guidance would be great

P.S. 88000 miles on the car and I JUST had the Timing belt replaced a few weeks ago.

Thanks! -Dan

 

You have a blockage in the heater core. The coolant portion of heat system is in parallel with the rest of the coolant passages, and only uses a small flow. Your car has a partial blockage that requires increased pressure (from higher RPM while driving) to get the coolant to and through the heater core where you can get heat.

 

Any easy fix for this, or do i need to remove the heater core and remove the blockage??

Thanks for the reply by the way!

 

The blockage could be nothing more than air, and there are searchable DIYs on how to bleed it. You can also use a solution of boiling water and CLR to break down a mineral clot - search for "heater core CLR" or something to that effect and you'll find it. It can be tedious but it definitely beats pulling the core - 10-12 hours of labor to replace a $50 part kinda sucks.