20v Heater Valve
Thread Starter
Audiworld Junior Member
Joined: Jul 2010
Posts: 15
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20v Heater Valve
My 91 90 20v takes forever to get heat, and when it does, it's not very strong. According to 20v.org, a common cause of this is a malfunctioning heater cutoff valve. This is supposed to be located at the back of the engine block near the firewall. There also supposedly is a vacuum line that connects to the valve that I have also failed to locate. Does anyone have any more information on where this thing is?
The thermostat was replaced a couple years ago, so I am ruling that out for now. I have not tested to see if the heater valve control motor is working, but I thought I should confirm that I actually have a heater valve first. There seems to be confusion in some of the previous forums about which models have the valve and which ones do not.
Thanks.
The thermostat was replaced a couple years ago, so I am ruling that out for now. I have not tested to see if the heater valve control motor is working, but I thought I should confirm that I actually have a heater valve first. There seems to be confusion in some of the previous forums about which models have the valve and which ones do not.
Thanks.
AudiWorld Senior Member
Joined: Apr 2007
Posts: 1,532
Likes: 5
From: Canada
Re: 20V Coolant shut-off valve...
It looks something like this (see below):
http://www.autopartswarehouse.com/im...1331626977.JPG
Use the two small diameter (5/8" ID?) coolant hoses themselves in between the engine block and the firewall to guide your search for said valve. As these two hoses connect the heater core to the cooling system, the valve has to be in one of them.
The B4 V6 90's don't have this valve, but if you have Climate Control (i.e. buttons vs dials), then I think your B3 should have this item.
Don't assume your T-stat is fully functional, as new ones failing a pre-installation temperature test is oft discussed on the forum. Does your engine reach full operating coolant temperature (see owner's manual for gauge reading discussion)? Does it stay fully warmed-up on the high-way?
Re: "My 91 90 20v takes forever to get heat, and when it does, it's not very strong", this could also be an air bubble in the heater core issue, do a search here on this forum to see the various cooling system bleeding discussions related to cabin heat.
http://www.autopartswarehouse.com/im...1331626977.JPG
Use the two small diameter (5/8" ID?) coolant hoses themselves in between the engine block and the firewall to guide your search for said valve. As these two hoses connect the heater core to the cooling system, the valve has to be in one of them.
The B4 V6 90's don't have this valve, but if you have Climate Control (i.e. buttons vs dials), then I think your B3 should have this item.
Don't assume your T-stat is fully functional, as new ones failing a pre-installation temperature test is oft discussed on the forum. Does your engine reach full operating coolant temperature (see owner's manual for gauge reading discussion)? Does it stay fully warmed-up on the high-way?
Re: "My 91 90 20v takes forever to get heat, and when it does, it's not very strong", this could also be an air bubble in the heater core issue, do a search here on this forum to see the various cooling system bleeding discussions related to cabin heat.
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