crowvet Posted December 27, 2018 Share Posted December 27, 2018 Hello, On my recently acquired 65, I noticed the heater control valve has been by passed, and the vacuum hose at the valve blocked off. There is a new valve in the trunk. I plugged the vacuum line to it and it closes in the warm position and opens in the cold position. I read a previous post that 64 valves are polar opposite of 65's, so I am pretty sure that is what I have here. Funny thing is the heater and defrost seem to work well without it. Why couldn't the valve I have just be installed backwards?? While looking at replacement valves most manufactures are listing them for 63 thru 65, or 65 thru 68 ect. I don't see how this is possible and don't know what to purchase. Anyone been there done that? and if so what valve did you use, part # Link to comment Share on other sites More sharing options...
RivNut Posted December 28, 2018 Share Posted December 28, 2018 Each of the 1st generation heater control valves are different. The 63 and 64 are mechanical but the '63 sits on the firewall while the 64 sits on the inner fender. The 65 is vacuum and sits at the front of the intake manifold. Until you're absolutely sure of what you need, contact someone on the forum and ask. Sellers are notorious for misrepresenting what they're selling. Whether it's intentional or just thinking that "all 63, 64, and 65 Rivieras are just alike" is a problem that you'll have to deal if you take for granted what they say as gold.. Most individuals just don't know (and they don't care to learn.) That big online catalog store just tries to sell you what they think should fit without having any real knowledge. 1 Link to comment Share on other sites More sharing options...
1965rivgs Posted December 28, 2018 Share Posted December 28, 2018 Daryle, The `65 valves are completely different from `63-`64 valves which are NOT vacuum operated. Sounds like you have an incorrect valve. Your local auto parts store should have one, probably in stock, as there is a huge application for the valve. Cost should be under $20. Be forewarned, if you have all the components of the original setup, most aftermarket valves cannot be secured with the original "clip". The original valve has a slot in the body which accepts the clip and the aftermarkets do not. Tom Mooney 1 Link to comment Share on other sites More sharing options...
crowvet Posted December 28, 2018 Author Share Posted December 28, 2018 15 minutes ago, 1965rivgs said: Your local auto parts store should have one, probably in stock, as there is a huge application for the valve. Thanks Tom... What would that application be? Link to comment Share on other sites More sharing options...
RivNut Posted December 28, 2018 Share Posted December 28, 2018 (edited) When you log into Rock Auto and find the part you need, you can click on the part number and it will tell you the other applications for that part number. In this case the part number is in blue whereas the rest of the description is black. Click on the blue number for other applications. BUT as you'll notice, the part number for the '65 shows it to be the part number for a '64 and we know that's not correct. So be careful. Look at a picture of the physical part. In this particular case the part is a Four Seasons 74604. If Rock Auto is out of stock or you think you can find it locally, then you can google that part number and see what pops up. https://www.rockauto.com/en/catalog/buick,1965,riviera,6.6l+401cid+v8,1319329,heat+&+air+conditioning,heater+valve,6860 Google results https://www.google.com/search?q=four+seasons+74604&oq=four+seasons+74604&aqs=chrome.0.69i59j69i60j0j69i61j69i60.12759j1j8&sourceid=chrome&ie=UTF-8 Edited December 28, 2018 by RivNut (see edit history) Link to comment Share on other sites More sharing options...
crowvet Posted December 28, 2018 Author Share Posted December 28, 2018 Thank you Ed, My concern is as follows... Although the one I have looks correct and is vacuum operated, it is closed under full vacuum (warm) and open under low vacuum (cold) I am concerned although it looks correct the polarity of it may be backwards. I will check the part # you provided with my local Napa. They deliver to me, and I could check it to be sure. You are a valuable resource and I appreciate the effort you always put into helping out. Link to comment Share on other sites More sharing options...
crowvet Posted December 28, 2018 Author Share Posted December 28, 2018 (edited) 34 minutes ago, RivNut said: In this particular case the part is a Four Seasons 74604 Ed,Oreillys had this part, and in fact the description says valve is open under vacuum... Sounds correct, so I ordered it. I will let you know how it worked out. Edited December 28, 2018 by crowvet (see edit history) Link to comment Share on other sites More sharing options...
crowvet Posted December 30, 2018 Author Share Posted December 30, 2018 Update, The valve Ed recommended works good. I now have a properly working heater. The Part# from Rock auto is also the same part # for Murray in stock at O-Reileys. Thank you all, another problem solved. Link to comment Share on other sites More sharing options...
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