Heater Control Valve Saga

Mike Miller mikemilr at blackfoot.net
Sat Nov 25 22:17:49 EST 2006

I just got back from a trip from Montana to Las Vegas ( and return ~ 2k 
miles). On the 2nd day there (Saturday), after basically idling in traffic 
for over an hour in the 80 degree temp, the heater control valve let go - 
this after a new heater core, blower motor and flaps motor about 6 weeks 
ago. I ordered a new part from a local auto parts store on Sunday - they 
flew it in from Phoenix on Monday for a total cost of $29.99 - great service 
and price - if only it had been the correct part. Sunday I wallked about a 
mile to Home Depot (with old part in hand) and bought a 5 inch long 
galvanized threaded 1/2 inch nipple for under a buck and bridged the two 
hoses that connect to the heater control valve, leaving the electrical 
connection hanging and I just plugged the vacuum line. Heating and cooling 
still appeared to work fine. I ordered another valve from a different place 
on Monday night and received it Wed. morning. This time the correct part at 
a cost of $63 in an "official" Audi parts box. I thought Napa made an all 
metal valve, but they were unable to match anything up and lacking reliable 
Internet access, I was unable to contact the list for help.

My suggestion would be for people to carry a 1/2 inch dia (inside), 5 inch 
long piece of galvanized pipe (I think the threads help hold the hose on) 
along with a couple of hose clamps just in case. I also found it easier to 
use a 6mm wrench on the hose clamps vs. a screw driver - even a "stubby" 
didn't work as well as the small wrench. I lost about a gallon of coolant 
and the part whole replacement took maybe 20 minutes. PVC and CPVC didn't 
seem to fit as well as the galvanized pipe - I suspect due to the different 
OD thicknesses. I would also question the PVC/CPVC ability to handle the 
temperature as they seemed to max out around 80c.

back in MT to 8 inches of snow 

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