Hello - I have a Oldsmobile 307 engine that lives inside my 1987 Cadillac Brougham. I replaced the intake manifold gasket because it corroded on the front drivers side and was leaking coolant. While I was at it I decided to replace the heater control valve with a brand new one. Of course on first startup the brand new one is leaking coolant from what appears to be the vacuum diaphragm (something about if it ain't broke don't fix it).

I am going to buy another new valve and replace it. However I've been down this road before with heater control valves in my Jeep and I may replace the brass valve with a brass fitting and put a plastic universal heater control valve in between. This way when the valve inevitably fails I can replace it much easier.

The question is - as I understand you cannot just hook up the heater core without a valve because the valve adds restriction and protects the heater core. Will this universal GM heater control valve linked below add enough restriction or am I risking ruining my heater core by using the wrong part?

https://www.rockauto.com/en/moreinfo...pt=6860&jsn=10

Finally - my original heater control valve had a sensor on the back which as I understand it is used by the automatic climate control system. The original sensor fell apart in my hands when I tried to unthread it (using my hands, not even a wrench). I need to replace it but I am having a hard time finding it. I know this part is probably Cadillac specific and not Oldsmobile but any pointers are appreciated.

Thanks for any help!

Update - thanks for all the feedback! I picked up the chevy style plastic one and my plan is to replace the valve with that one when I need to.

 

The heater control valves available today for this application are crap. I even paid dearly for a Delco brand valve from GM and it failed in a month. I finally installed a nipple and used the in-line valve for a Chevy. This valve is plastic, so it doesn't corrode, and since it's inline in the heater hose, replacing it is trivially easy.

 

Ok, I think that's the same or very similar part. Sounds like I am on the right track with my thinking. Thanks for the reply!

 

As I recall @Oldsguy used a brass hose nipple in place of the control valve in his 69 Delta 88 and didn't have any heater core troubles.

 

If you use a hose nipple on the intake, ensure there is a restriction somewhere in the system or you run the risk of blowing out the heater core. I blew out 2 cores before I realized a restriction was needed. One freshly installed core blew on the first 5000RPM pull. On first startup there was a loud water rushing noise that should have been a clue for me, but I didn’t realize at the time what it meant. Either make one in the hose nipple or ensure the heater valve has one built in.

 

The heater valve that I showed has sufficient restriction. Ran one for years in an 84 Custom Cruiser.

 

Joe, I think the only problem with that style of valve is that the diaphragm is actually exposed to the coolant flow. If the diaphragm blows, lets just say that you had better be watching the temp gauge because you can say goodbye to all your coolant. Ask me how I know.

 

That’s the same as the factory Olds valve.

 

I'm thinking that the huge white steam cloud when the coolant hits the exhaust manifold will be the giveaway...