Sorry if this is a common knowledge but I'm pretty new to working on cars, recently my 1971 Delta 88 has been leaking coolant and I found out it's coming from this part I've circled in red, I don't know the name of it and all the service manuals I own don't point this part out. could you tell me what this part is called?

Leaking part
Sorry if the picture is a bit blurry I have an old phone.

thanks in advance!

 

Welcome!!! NO need for apologies, forum knowledge varies widely with many experts in various areas. Members are pros, hobbyists and newcomers to auto repair.

The circled part is referred to as a heater valve or a water control valve. It is operated by vacuum opening and closing to allow or stop hot coolant from flowing into the heater core. Be careful with the one you select, some open by vacuum some close by vacuum. Someone please jump in, what type or part # does the OP need?

It is easiest to cut the top off of the old one and then drop a socket onto the piece left in the manifold to remove it.

Good luck!!!

 

Thank you for the reply, I'll do some more research and see if I can find the exact one I need!

 

Note that many vendors list this part incorrectly. You need a heater valve that is normally open and closes when vacuum is applied.

 

Joe, Is the closed with vacuum "across the board" for Olds RWD?

 

No, and that's the problem. Initially, Olds used valves that were normally closed and only opened with vacuum applied. Obviously this has a potential failure mode of no heat in the winter. The valve design was changed to the "fail safe" normally open design when body styles changed. That means that the change happened on the full size and Toro lines during the 1971 model year redesign, but the A-body valve didn't change until the 1973 redesign. From 1973-on, all Oldsmobiles used the normally open valve.