Ok....I just replaced all my heater hoses, along with a new heater valve on my 90 RS 305 TBI. (The old one cracked and was leaking) Anyways....got all the new hoses and the new heater valve on, and now I still have a problem. The heater valve leaks when I have the heat turned off, or with the AC on, but when I turn the heat on full blast it stops. My guess is the valve has a small crack in it somewhere, am I right? It's driving me nuts....I had a hard enough tiem with a couple of those old heater hoses. Any opinions out there? Do I have a defective heater valve?

PS-If I would decide to bypass.....will I still have cold AC and warm heat? Thanks in advance!

 

Do I have a defective heater valve?

Probably/would say yesor the wrong hose size so it won't tighten enough to seal.

If I would decide to bypass.....will I still have cold AC and warm heat?

No. Your AC will work,but you will not have heat.

 

It depends on what you mean by "bypass". If you just ripped out all the heater hoses and capped off the connection on the radiator, than you wouldn't have any heat. But, if you removed and rerouted the heater hoses so that the heater valve could just simply be deleted, than you'll still have heat. Here's a link to how to delete the heater valve: http://www.thirdgen.org/techbb2/show...hreadid=242747

That's how mine is done, and everything still works properly. Your AC will still blow cold and your heat will still blow hot. One thing to keep in mind is that having the heater valve deleted means that the coolant is constantly running through your heater core, so if it's leaking (usually characterized by puddles of coolant on the passenger side carpet), it's going to get worse. And, actually, GM ran their heater hoses like this for years and years, I don't know why they started using those heater control valves.


But, since I mentioned that, I know your probably wondering: "If hot coolant is always running through the heater core, won't hot air come out of the vents and my AC will not blow cold? The answer is no. There are various doors in the HVAC system that block off or open certain passages, and one of them is for the heater core. The door for the heater core is only open when you want heat. People ask that ALL the time on TGO when people start talking about deleting the heater valve, just figured I'd clear it up.

 

Thanks guys, sure appreciate the help!

 

I agree with IROC-T You are suppose to have 2 different size hoses going to the heater box and valve.

 

Yeah, I have the right hoses. I know they are different.

 

Did you get new hose clamps? If not, try that.