I have an 87 firebird with a 2.8L. I have replaced the heater control valve 3 times. I don't drive the car at all on the road due to work that needs to be done. As soon as the temperature gauge gets to normal operating temperature, I look at the valve and it has started leaking. I dont know if it has to do with the heater controls inside or if there is a blockage somewhere under the hood. I do know I need to rebuild the cooling system at this point, but wasn't sure if there was a known issue with these heater valves. Also, when does that vacuum line going to the valve have vacuum pulled on it?

 

They are known to leak over time. your best bet is to find one, possibly you can get one from an autoparts store.

 

Yes the valve is available. They're $20, but I've replaced it 3 times and it keeps leaking and I never drive it. I replace it, start the engine and as soon as it starts heating up it starts leaking. I replaced all the hoses and clamps.