old-tank Posted September 9, 2022 Share Posted September 9, 2022 Slipping and squealing V-belt: not specifically Buick (but don't move the post since Buick guys are the smartest ). AC belt on my 76 Olds 455. Tried 3 brands of belt with no change and 2 different belt dressings that help...for 20 miles. Pressures are reasonable. It started when I replaced a leaking and slobbering A6 compressor and the oil (ester) and desiccant bag in the VIR system and charged with R134a. Research showed that the old VIR system will not work with other than R12, so I changed to a cycling system...still slipping. Replaced the condenser with a parallel flow unit...still slipping. Replaced the compressor 3 times and ended up with the A6 upgrade unit (big old ugly aluminum unit). The cooling is great with no slipping as long as I drive carefully and less than 60 mph. Link to comment Share on other sites More sharing options...
EmTee Posted September 10, 2022 Share Posted September 10, 2022 I went to Rock Auto to see what they had for belt options. Interestingly, reading the technical descriptions seems to indicate a difference of opinion with regard to design philosophy between Gates and Dayco. Here's what Gates says about their belt: And here's the blurb provided by Dayco: Note that Gates claims: "Due to thermal forces, this variable notched belt tightens on the drive as it gets hot. This results in improved belt performance by reducing tension decay and noise." On the other hand, Dayco says: "Dayco® was first to develop a v-belt with the raw edge sidewall construction, which facilitates controlled slippage around pulleys." Based on the claims above, I'd be tempted to give the Gates XL High Capacity V-Belt a try... 1 Link to comment Share on other sites More sharing options...
old-tank Posted September 10, 2022 Author Share Posted September 10, 2022 I tried Gates AC Delco and one from Off-road belts. I may have to try the Dayco since the other designs did not work. I did not consider the dayco since judges did not like that design on one of my projects I submitted for judging. If that doesn't work I may have to rig an idler pulley to increase the wrap on the air conditioning compressor pulley. Link to comment Share on other sites More sharing options...
EmTee Posted September 10, 2022 Share Posted September 10, 2022 My '67 Riviera is like your Olds; single belt and not much contact area. It has to be very tight or it squeals. Did Olds use a double pulley setup on any cars that would be a candidate to swap to your '76? The idler might be simpler than a wholesale pulley swap, though... Are you sure the belt is tight enough? New belts will stretch a lot at first, which means a lot of re-tightening until it is fully broken-in. Link to comment Share on other sites More sharing options...
old-tank Posted September 10, 2022 Author Share Posted September 10, 2022 30 minutes ago, EmTee said: Are you sure the belt is tight enough? Probably too tight....and still slipping. 1 Link to comment Share on other sites More sharing options...
195354 Posted September 10, 2022 Share Posted September 10, 2022 Did you flush the system with a solvent for Freon systems. I can’t think of the name of the flush we use at the moment. With a bit of oil left in the condenser or evaporator it will build up with each new component. It is possible you have an oil over charged system. I Had a York compressor with 2 V belts would not stop making belt noise. Flushed system added correct amount of oil and it stopped talking back. Just a thought The flush is needed if Changing oil types did this have Pag oil when new? Steve Link to comment Share on other sites More sharing options...
old-tank Posted September 10, 2022 Author Share Posted September 10, 2022 Everything is new except the evaporator and that was flushed and is free flowing. Followed compressor recomendations on oil type and volume after draining 2 cc of shipping oil. Link to comment Share on other sites More sharing options...
NTX5467 Posted September 10, 2022 Share Posted September 10, 2022 By observation, GM usually spec'd the nothced belts for applications where the pulley was smaller (as in Cadillacs with the small pulley and 100amp alternators). Not sure why a belt would get tighter if it gets hotter, all things considered, but I could understand a rubber compound which might get grippier with additional heat. Has it been determined if it is the a/c pulley that's slipping or another one? Perhaps the "leaked" a/c oil bonded with the pulleys and might need to be "vatted out"? Never did have any luck trying to use "belt dressing compound" to fix a slipping belt, although others claimed to have good luck using it. Curiously, are the new belts .380" width or .440" width? Just some thoughts, NTX5467 2 Link to comment Share on other sites More sharing options...
old-tank Posted September 10, 2022 Author Share Posted September 10, 2022 0.41 I think is the specification on the belt. Revving the engine under the hood shows the AC compressor slowing or stopping. No oil present. 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted September 10, 2022 Share Posted September 10, 2022 What do the high/low side gauges read? Possible the pressure is getting too high causing the belt to slip. Link to comment Share on other sites More sharing options...
rocketraider Posted September 10, 2022 Share Posted September 10, 2022 Think it's time to check A/C system head pressures, since it appears the system is all R134a now. Rule of thumb when converting from R12 to R134a. Whatever the R12 design capacity of the system is, use 75-80% of that amount for the R134a charge. Example spec is 4 lbs R12, put 3 lbs R134a in. Otherwise you develop outrageous high side pressures, which can cause belt slippage and eventually clutch/compressor failure and leaks. I never did like those Valves-in-Receiver systems. 2 Link to comment Share on other sites More sharing options...
NTX5467 Posted September 10, 2022 Share Posted September 10, 2022 From my research, the VIR is just a miniature POA valve, with a different placement in the system. A functioning POA can be readjusted for use with R-134a, as can the VIR, too. Then start with the reduced charge level with R-134a. NTX5467 Link to comment Share on other sites More sharing options...
old-tank Posted September 10, 2022 Author Share Posted September 10, 2022 It is now a cycling system with pressures less than the old VIR. 1 Link to comment Share on other sites More sharing options...
old-tank Posted September 17, 2022 Author Share Posted September 17, 2022 On 9/9/2022 at 7:38 PM, old-tank said: I tried Gates AC Delco and one from Off-road belts. I may have to try the Dayco since the other designs did not work. I did not consider the dayco since judges did not like that design on one of my projects I submitted for judging. If that doesn't work I may have to rig an idler pulley to increase the wrap on the air conditioning compressor pulley. Dayco belt is working so far. So much for the marketing propaganda of the other belts. 2 1 Link to comment Share on other sites More sharing options...
EmTee Posted September 18, 2022 Share Posted September 18, 2022 1 hour ago, old-tank said: Dayco belt is working so far. I guess you'll just have to accept the point deduction... Link to comment Share on other sites More sharing options...
old-tank Posted September 18, 2022 Author Share Posted September 18, 2022 29 minutes ago, EmTee said: I guess you'll just have to accept the point deduction... No worries that car has it's work clothes on. 1 1 Link to comment Share on other sites More sharing options...
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