1985 Corvette heater control valve question.
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 1,194
Likes: 2
1985 Corvette heater control valve question.
Had to do a water pump on my 1985 Corvette so I decided now would be a good time to replace the heater control valve that has a very minor but annoying leak.
Bought the heater control valve from a well known supplier and when it came in I pulled a vacuum on it with a mityvac to confirm the valve works.
The valve would not move, I could not build any vacuum on the gauge and could hear a hissing sound at the valve.
The only way the valve would move is if I pushed the arm in part way then vacuum would register on the gauge and move the valve.
I compared this to my original one I wanted to replace and the valve moves as soon as I apply vacuum to it.
I called the company, told them the problem, asked them to test the replacement part they were going to send me.
Today I get the replacement part, I pull a vacuum on it and have the exact same problem, no movement on the valve unless I push in the arm part way.
Either I received two defective parts or I am missing something here but I doubt that I am because my original heater control valve responds right away.
Any thoughts on this?
Thanks.
Bought the heater control valve from a well known supplier and when it came in I pulled a vacuum on it with a mityvac to confirm the valve works.
The valve would not move, I could not build any vacuum on the gauge and could hear a hissing sound at the valve.
The only way the valve would move is if I pushed the arm in part way then vacuum would register on the gauge and move the valve.
I compared this to my original one I wanted to replace and the valve moves as soon as I apply vacuum to it.
I called the company, told them the problem, asked them to test the replacement part they were going to send me.
Today I get the replacement part, I pull a vacuum on it and have the exact same problem, no movement on the valve unless I push in the arm part way.
Either I received two defective parts or I am missing something here but I doubt that I am because my original heater control valve responds right away.
Any thoughts on this?
Thanks.
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 1,194
Likes: 2
Both parts are defective.
I put my original heater control valve back in but I joined the 3/4" line to the 5/8" line, the way it would be if the valve was in by-pass mode.
I did that so I could fill coolant and run the car to test the new heater control valves operation with the cars vacuum as opposed to using a Mityvac.
I placed the new heater control valve next to my original and hooked the factory vacuum line to the new one with the car running.
As it had done with the Mityvac, the arm would not move with the vehicle vacuum applied unless I pushed the arm in about 1/4" to 3/8", then the vacuum would pull the arm in all the way and close the valve.
Essentially, with the heat turned off, every time I would start the car I would have to open the hood and push the arm in until the vacuum would then pull it in.
I put my original heater control valve back in but I joined the 3/4" line to the 5/8" line, the way it would be if the valve was in by-pass mode.
I did that so I could fill coolant and run the car to test the new heater control valves operation with the cars vacuum as opposed to using a Mityvac.
I placed the new heater control valve next to my original and hooked the factory vacuum line to the new one with the car running.
As it had done with the Mityvac, the arm would not move with the vehicle vacuum applied unless I pushed the arm in about 1/4" to 3/8", then the vacuum would pull the arm in all the way and close the valve.
Essentially, with the heat turned off, every time I would start the car I would have to open the hood and push the arm in until the vacuum would then pull it in.
