heater problem

[Robert Cuttler]

I've got a '99 A6 that's not getting any heat.  I had the heater core flushed 
last year that helped some but only for a short period of time but before the 
winter was over I was getting no heat again.  The shop said I needed a new 
heater core.  Forgot all about it then as from March to November unless it's 
raining I'm on my bike not in the car.  Just took the car to a different shop 
and they say the core is not blocked.  They say water pump is not pumping 
enough to meet the needs of the engine cooling system and still push 
coolant through the heater core unless the motor is turning at least 2,000 to 
2,500 rpm, which it almost never does in local driving.  With the motor at 
proper temps, reving it in idle to 2,500 rpm did get hot air out of the heater 
vents.  The water pump had been replaced 35,000 miles ago when the 
timing belt was changed.  Does this make sense, that the water pump is the 
cause of the lack of heat?
Bob
rcuttler at optonline.net