Red Riviera Bob

63 Riviera AC vent doors opening and closing

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I just got my 63 Riviera out of the shop for AC repairs. The mechanic told me the doors keep opening and closing and he does not know off hand what the fix is.

The AC is blowing cold (24 degrees F ) and seems to be working fine for its system design. Is there a vacuum switch or something else might remedy the problem of the doors opening and closing on their own?

Many Thanks

Red Riviera Bob

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There's a very good system trouble shooting guide in the chassis manual.  LOTS of vacuum lines control the A/C system.  

Edited by RivNut (see edit history)
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11 minutes ago, RivNut said:

There's a very good system trouble shooting guide in the chassis manual.  LOTS of vacuum lines control the A/C system.  

Ed, fortunately I have the chassis manual that can be used to run down the problem.

Thanks for the guidance and direction.

Red Riviera Bob

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If you're blowing 24°, you might have issues with your evaporator freezing up.  Is your AC guy familiar with the STV and adjustment thereof?

 

BTW, are you running R12 or did you convert to 134A?

 

If you've got vacuum problems related to leaking diaphragms, you may have to fix them yourself, as replacements may not be available for all of them. I disassembled them and replaced the diaphragms with new rubber cut from an inner tube I bought at Walmart.  And if you need to remove the diaphragm on the bottom of the blower box, bone up on your profanity first.

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7 hours ago, Red Riviera Bob said:

I just got my 63 Riviera out of the shop for AC repairs. The mechanic told me the doors keep opening and closing and he does not know off hand what the fix is.

The AC is blowing cold (24 degrees F ) and seems to be working fine for its system design. Is there a vacuum switch or something else might remedy the problem of the doors opening and closing on their own?

Many Thanks

Red Riviera Bob

Be sure there is a vacuum check valve in the vacuum feed line. Otherwise, when engine vacuum is low, as in medium to heavy acceleration, the vacuum in the HVAC system can bleed back into the intake manifold and cause issues with the HVAC doors. There is a factory check valve at the intake manifold but they are often bad.

Having stated the above ANY vacuum leak in the system can cause overall vacuum level to be low and affect other areas/components in the system.

  Tom Mooney

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Tom, thank you very much for the insider information. I believe a vacuum problem exists somewhere. I suppose buying the factory check valve at the intake manifold would be a good idea.

Many thanks,

Red Riviera Bob

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1963 models do not have any vacuum reservoir for the A/C system.  That ends up causing the doors to close when you step on the gas, even if there is only a very small vacuum leak.  I added a small vacuum storage can (plastic) from a later model full size Buick to the vacuum supply line before the control unit on the inner fender.  This provides enough storage buffer to keep the vents in the correct position when you accelerate.

 

This very low air temperature sounds like the Suction Throttle Valve (STV) may be stuck on maximum or the diaphragm that controls it is not working.  Or it may need to be adjusted to a bit higher pressure/temperature.

 

The Thermal Expansion Valve should prevent the core from freezing.

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You'll also not find an NOS vacuum check valve.  Best thing to do is check with the "parts" vendors who advertise in the Riview's classified section.  Gene Guarnere, Bob Stemm, Steve Lorenzen come to mind as possible sources.

 

Ed

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8 hours ago, Jim Cannon said:

1963 models do not have any vacuum reservoir for the A/C system.  That ends up causing the doors to close when you step on the gas, even if there is only a very small vacuum leak.  I added a small vacuum storage can (plastic) from a later model full size Buick to the vacuum supply line before the control unit on the inner fender.  This provides enough storage buffer to keep the vents in the correct position when you accelerate.

 

This very low air temperature sounds like the Suction Throttle Valve (STV) may be stuck on maximum or the diaphragm that controls it is not working.  Or it may need to be adjusted to a bit higher pressure/temperature.

 

The Thermal Expansion Valve should prevent the core from freezing.

Jim,

  The `64 and `65 vacuum cans have an internal check valve, perhaps the can you installed does also. My `84 and `85 also have an external check valve. I had to eliminate the check valve at one time because the nipple broke off and had the same problem with the HVAC doors as the earlier models with a bad check valve.

  Tom

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KongaMan

I have that dual diaphragm removed from the air box on my 63. Of course I cannot  find a replacement. I never thought I could repair this one.Any words of wisdom would be appreciated.

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5 hours ago, Chasander said:

I have that dual diaphragm removed from the air box on my 63. Of course I cannot  find a replacement. I never thought I could repair this one.Any words of wisdom would be appreciated.

 

It's been a while since I did this, but I remember it as being pretty straightforward:

- Separate the two halves by opening the crimp and pulling them apart.

- Cut a new diaphragm from the inner tube.

- Remove the plunger from the old diaphragm and attach it to the new one.

- Put the new diaphragm back in the shell, with a light bead of sealant around the edge.

- Put the two halves of the shell back together and squeeze/hammer the crimp back down.

 

Before you do this, I'd suggest that you double check that the diaphragm is at fault (you'd hate to do this just to find out the problem is a leaky hose or a mechanical problem with an air door ;) ).  Plug one port and suck on the other.  Does it hold vacuum?

 

You might also find this helpful: http://www.chip.com/buick/techtips/dual-stage.html.

 

And if you would rather get a replacement, Old Air Products has one.  They also sell a vacuum check valve.  I have no experience with either part, and can't vouch for their suitability or performance.

Edited by KongaMan (see edit history)
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When testing the dual diaphragm units, be aware:  To test the 1/2 way back operation, apply vacuum to only the outer port.  It should hold.  Then to test the full pull back operation, apply vacuum to both nipples (not just the center port).  It should hold vacuum.  If you only apply vacuum to the center port, it will leak and act like it is bad when it is not.

 

 

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36 minutes ago, Jim Cannon said:

When testing the dual diaphragm units, be aware:  To test the 1/2 way back operation, apply vacuum to only the outer port.  It should hold.  Then to test the full pull back operation, apply vacuum to both nipples (not just the center port).  It should hold vacuum.  If you only apply vacuum to the center port, it will leak and act like it is bad when it is not.

 

As I mentioned earlier, it's been a while (like maybe 15 years) since I disemboweled mine, but if you apply vacuum to the center port and plug the outside port, it should hold, correct?  That is, the key is plugging the outside port.  IOW, there is (I think) a check valve in the center port which holds it shut until vacuum is applied, but the outer port is just a hole.  Which is why applying vacuum to the outside port only will hold, but the center port only will not.

 

Am I misremembering this?

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Yes, plugging the outer port also works.  Or apply vacuum.  The main thing is to not leave it open.

 

 

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That actually raises another issue.  If vacuum is applied to the outside port and it doesn't hold, try again while manually plugging the center port.  If it holds then, you'll know it's the check valve/second stage and not the diaphragm.  If that's stuck open, you may be able to free it up by moving the actuator rod back and forth and/or gently blowing through the center port.

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On 8/2/2017 at 6:43 PM, 1965rivgs said:

Be sure there is a vacuum check valve in the vacuum feed line. Otherwise, when engine vacuum is low, as in medium to heavy acceleration, the vacuum in the HVAC system can bleed back into the intake manifold and cause issues with the HVAC doors. There is a factory check valve at the intake manifold but they are often bad.

Having stated the above ANY vacuum leak in the system can cause overall vacuum level to be low and affect other areas/components in the system.

  Tom Mooney

Tom, thanks again for your valuable input on my AC problem. I now have cold Air. The volume of air coming from the vents is low as I have described, but will a properly functioning AC in a 63 Buick Riviera cool ( R12) the cabin in say 15min- 20 min? I'm only talking about comfort level for 2 people in the front seat in 90 degree weather with high humidity we have in central Maryland during the summer months. ( I do not need to store refrigerated products :-)) )

I understand an AC system that is working right from 1963 Riviera is not going cool like a full size year 2017 GM car.  My next steps are to put on an AC vacuum canister on the inner fender with check valve in the proper position. Additionally, I'm replacing the #1 vacuum switch ( 1194602 ) AC control on the panel under the hood. I wouldn't mind performing another leak test as well. Assuming there are no leaks AND the AC system is functioning as it should AND with the additional repairs should I experience a significant level of cold air volume? I know the word significant can mean different things to different people.

Thanks again.

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27 minutes ago, Red Riviera Bob said:

Tom, thanks again for your valuable input on my AC problem. I now have cold Air. The volume of air coming from the vents is low as I have described, but will a properly functioning AC in a 63 Buick Riviera cool ( R12) the cabin in say 15min- 20 min? I'm only talking about comfort level for 2 people in the front seat in 90 degree weather with high humidity we have in central Maryland during the summer months. ( I do not need to store refrigerated products :-)) )

I understand an AC system that is working right from 1963 Riviera is not going cool like a full size year 2017 GM car.  My next steps are to put on an AC vacuum canister on the inner fender with check valve in the proper position. Additionally, I'm replacing the #1 vacuum switch ( 1194602 ) AC control on the panel under the hood. I wouldn't mind performing another leak test as well. Assuming there are no leaks AND the AC system is functioning as it should AND with the additional repairs should I experience a significant level of cold air volume? I know the word significant can mean different things to different people.

Thanks again.

Low volume from the AC registers is generally attributable to the vacuum actuator located at the upper pass side of the firewall. There should be mechanical linkage which is exposed enabling you to judge whether the vacuum can is pulling it all the way to the limit of its travel. If not, one can physically pull the linkage toward the can and block it there to direct full blower volume to the AC registers.

If the can is not performing properly it could be due to low vacuum or the can is bad. Both possibilities are very common. I would suggest simply replacing it rather than trying to "rebuild" it. We are fortunate a replacement is available!

Keep in mind there can be other causes for low volume like air leaks in the post blower system. Hope this helps,

 

  Tom

 

PS The original systems can blow ice cold, ie 36 degrees F at the pass AC vent, but if using R134 results will be less. In addition to the efficiency of the AC refrigerant system one must consider whether the cabin is well sealed. The first gen Rivs leak air profusely so good weatherstripping and sealing at the frameless glass interfaces is very important to keep cabin temps low enough to be comfortable in challenging conditions.

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1 hour ago, Red Riviera Bob said:

...will a properly functioning AC in a 63 Buick Riviera cool ( R12) the cabin in say 15min- 20 min? I'm only talking about comfort level for 2 people in the front seat in 90 degree weather with high humidity we have in central Maryland during the summer months. ( I do not need to store refrigerated products :-)) )

 

I've got a 63 Electra that will get meatlocker cold.  The 64 Riviera never worked as well, but it worked well enough to handle Texas, so it wasn't that bad.  I've since converted the 64 to R134A (so the performance has diminished a bit), but it still gets the job done.

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Mr. Konga Man, thank you for giving the info I have been looking for. The AC in the 63 can, and I hope, " Get the job done."

I'm not a mechanic so I've had to p a y for all the work done and it's starting to creep to a number I don't want to admit. The forum gives me some solace in knowing I have some knowledge about the subject to protect myself. I source all the parts and hand the goods over to what I believe is a good shop.

thanks for the input, I really appreciate the help you guys provide.

Red Riviera Bob

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1 hour ago, 1965rivgs said:

Low volume from the AC registers is generally attributable to the vacuum actuator located at the upper pass side of the firewall. There should be mechanical linkage which is exposed enabling you to judge whether the vacuum can is pulling it all the way to the limit of its travel. If not, one can physically pull the linkage toward the can and block it there to direct full blower volume to the AC registers.

If the can is not performing properly it could be due to low vacuum or the can is bad. Both possibilities are very common. I would suggest simply replacing it rather than trying to "rebuild" it. We are fortunate a replacement is available!

Keep in mind there can be other causes for low volume like air leaks in the post blower system. Hope this helps,

 

  Tom

 

PS The original systems can blow ice cold, ie 36 degrees F at the pass AC vent, but if using R134 results will be less. In addition to the efficiency of the AC refrigerant system one must consider whether the cabin is well sealed. The first gen Rivs leak air profusely so good weatherstripping and sealing at the frameless glass interfaces is very important to keep cabin temps low enough to be comfortable in challenging conditions.

Tom, Im making progress and hopeful what I've spent on bell arm replication in the HVAC control panel, installation, compressor, drier, hoses, R12 and the like haven't been for a half baked system. I bought a rebuilt STV and Actuator from Old Air and had that installed along with the compressor and drier. So, with a good vacuum reservoir and check valve and all the stuff working properly I should be cool enough. Oh, when I had the upholstery installed with carpet I had ALL the weather stripping replaced at the same time. New weather stripping should help plug up the holes.

Thanks again for. your support.

Red Riviera Bob

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Does Old Air offer a true STV these days?  They used to offer only a "replacement" that was little more than a thermal switch that cycled the compressor on and off. That is, they completely subverted the original design of the system.  I didn't like the idea of cruising down the road with the compressor constantly slamming on and off.

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1 hour ago, KongaMan said:

Does Old Air offer a true STV these days?  They used to offer only a "replacement" that was little more than a thermal switch that cycled the compressor on and off. That is, they completely subverted the original design of the system.  I didn't like the idea of cruising down the road with the compressor constantly slamming on and off.

That's the way all modern systems work.  Your A6 compressor is very tough and reliable.  I know many folks who've made this adaptation and are very happy with it.

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Gents, Old Air rebuilt a core STV for my 63 Riviera. Old Air included the Actuator as well, now it was pricey. Nonetheless, it came back all pretty and installed on my 63. I wanted to stay with R12 and original design with the STV. The idea of an update kit did not sit well with me. I don't know much, but I know some things. ( I'm not the guy who wants to fight a battle with bows and arrows when a machine gun is available and working )

Old Air does not sell new STV ( to my Knowledge ) , but they will rebuild yours if you provide the core. I understand old air will rebuild to your specifications.

Hope this sheds some light.

TedRiviera Bob

Edited by Red Riviera Bob
Forgot "did not" (see edit history)

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