Topic: Where is the heater control valve located
in Forum: C3 Cooling and Heating Systems
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
Where is the heater water cut-off valve located on my '75, and how do I access it?
SPONSOR AD:: (Our Sponsors help support C3VR)
Limited Member
Send PM
Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.
2023 Accelerate Yellow HTC Stingray
I am not sure that the 1975s had one but if they did, it would be in the heater hose line going to the core. I believe it would have a small vacuum line going to it.
1973 L-82 4 spd
Okay, it is not in the engine compartment, so I didn't know if it was within the heater box. Thanks for the response.
My heater does not put out much heat, so before I tried flushing the heater I thought I'd see if a valve was stuck.
I'm not sure any corvettes had a shut off. I added a shut off and I think that is what everybody does!
But Corvette America lists a "heater/water control shutoff valve - #41033" which has a vacuum control on it.
I did add a water shutoff valve in the heater hose, which did help in the Summer, but I'm not getting much heat now that it is cold out. I'll try flushing the heater core next.
Thanks for the responses.
Lifetime MemberSHELBYVILLE, TN - USA
Joined: 7/5/2002
Posts: 3942
Vette(s): 1976 L48 auto
1978 L82 4speed
1994 LT1 6speed
1978 L82 4speed
1994 LT1 6speed
usually the original shut off was located between the heater core and the engine block. it kinda looks like a crooked letter "P" with one hose going in and another going out, with a small vacuum line somewhere in the middle.... was not one of GM's best designs, and typically they stopped working and were usually taken off or replaced with a gate valve of some sorts... or some of us would just disconnect the hose all together and route it back to itself on the core, and the other hose from the pump to the intake..... of course when colder weather comes around, would have to route them properly to get a little heat inside... 
here is a picture of the control valve...hopefully,
StingrayJim 
NCM Lifetime Member #1936
Stingray's '76���������������������������� StingrayJr's '78���������������������������Lil Red '94 
(click each one to see a bigger version)
On my 75' the Heater Valve is in the engine bay on the passenger side connected to one of the heater hoses about a foot from the fire wall.
Hope this helps.
Trent.
in Forum: C3 Cooling and Heating Systems
SPONSOR AD: (Our Sponsors help support C3VR)