Rustbucket2

Do I have to use this style of heater valve, to make everything work right on my car , is a a/c car. ( 1st Pic ) or can I use this other one ( 2nd pic ). I was surprised to find a aluminum intake under that grease ! My cutlass is missing heater valve, pics are from my parts car.

Fun71

The second picture is the typical Olds heater control valve that is available from parts stores, resto houses, NOS, etc. You can use any type of valve to control coolant flow through the heater core, but be aware there needs to be a restriction in either the valve or the hose nipple. I used a manual valve with an unrestricted nipple and the heater core expanded and blew a seam. The factory valves and nipples have a 1/4" hole for the coolant to pass through, and this restriction prevents the issue I had.

joe_padavano

A 1970 Cutlass uses a valve that is normally closed and opens when vacuum is applied. If you can blow through the new one without vacuum applied, it won't work properly. If you cannot blow through it, and assuming the pipe threads are the right size, yes you can use that one.

Rustbucket2

Joe, I can blow through it! Any idea were I can get one that works? maker, supplier, part # ? any help is appreciated.

costpenn

That valve in the second picture I believe is for big cars that have the automatic temperature control system. Does it work the same as the regular A body valve?

tru-blue 442

http://www.rockauto.com/en/moreinfo....217472&jsn=409

This should be it. Also note the size of the hole in your intake. The one for 69-70
is smaller than the 71 up like the stand alone one in your pic.

I just noticed you have an AL intake, all bets are off. What I posted is for factory intakes.

joe_padavano

Actually, many of the aftermarket replacement valves have that feature for the temp sensor but can be used without it. It's a blind hole, so it works fine in the manual A/C systems also. Lets the vendors stock one less part since one P/N fits both applications.

The break from normally closed to normally open valve corresponds to model year breaks, so it is different for full size and A-body. The A-body cars used normally closed through the 1972 model year, and changed to normally open with the redesigned 1973 cars. The full size used normally closed through the 1970 model year and changed to normally open with the redesigned 1971 cars. There is one additional wrinkle here in that the 1971 intakes used a larger threaded port for the valve than did the early cars. This means that the 1971-72 A-body valve is unique (large thread and normally closed). Unfortunately, all the aftermarket listings I've seen show the same valve P/N for the 1971 A-body and full size cars. This is not correct, and the factory parts book obviously indicates the difference - 407738 for the A-body cars and 410572 for the full size. And for completeness, the factory P/N for the 68-70 cars is 399679 for all A-body and full size except the automatic A/C (which is 399715).

Be careful when ordering an aftermarket replacement. As with motor mounts, the catalogs are frequently incorrect.

Bfg

My 65 442 A/C car has a valve unlike the ones seen here. My valve is mounted on a bracket and the heater hose goes into a nipple towards the rear of the intake. I was told there was no restriction on this particular valve. Don't know if that is true or not?

joe_padavano

Yes, that is what was used on the 65 cars.

KardsHO

Very interesting thread that has me asking the following question. I have a 72 Hurst Olds that I had a W-30 intake intake installed on and need the smaller (believe its 7/8" valve). What if any issues would I run into with valve on a 72 AC car?

joe_padavano

So long as you use the normally closed valve, it will work fine. The A-body cars used the normally closed heater valve through the 1972 model year, so both large and small thread are available.