What's best AC compressor to buy?

[sweetp01569]

Driving the car yesterday in MA, with my AC on, I hear a big "Whoosh" from the engine compartment and loss of my AC. After pulling in at home and taking a look, the rear part of the compressor (original) with the threads that hold the compressor hose bracket broke away from the main body of the compressor! The threaded piece of casting just broke apart, with screw and both hoses still attached. Is there too much pressure somehow or just old? It looks like I need to buy a new compressor, and wondered what the best choice is? Thanks, Paul

[Chris4099]

For replacement compressors, you have two choices from the venders. The first being an NOS from DMCH. The other a new unit from SpecialTauto. However, since the back plate is no longer made, you normally have to transfer it over on new units. Since yours is broke, you are pretty much stuck with the NOS unit from DMCH unless you can find someone with a spare back plate.

[sweetp01569]

Are you saying the new one from John does not have the threaded hole to secure the screw and plate that holds the hoses?

[Chris4099]

When I ordered a compressor from John, it did come with a refurbished plate on the back. However, those plates aren't made anymore by Sanden and I had to send my old one back to him to avoid a core charge. Usually not a big deal as they don't normally fail like yours. You could still give John a call and see if he has any available for sale.

In Houston's case, they just grab another 30 year old compressor with back plate off the pallet:
448

[stevedmc]

For replacement compressors, you have two choices from the venders.

Or you could get one from ebay like Bill has done in the past. I'm not sure if he has to modify the compressor or not though. My guess is he just transfers the back plate.

[Chris4099]

Or you could get one from ebay like Bill has done in the past. I'm not sure if he has to modify the compressor or not though. My guess is he just transfers the back plate.

I remember he had to do some modification to it. It was either transfer the back plate, the clutch or both. Unfortunately the OP is in the unique position of having a damaged back plate which limits the options.

[stevedmc]

I have been doing some reading and it looks like any SD508 or SD510 compressor would work fine but you do need to swap the back plate.

He would do best just ordering one from DMCH since he needs the whole thing.

Back to the title, I wonder which one is the best. What reading I have done says the SD510 is stronger but Hervey is selling the SD508.

[sweetp01569]

I decided to go with a new SD 508 from Hervey, versus NOS that is 30 years old. Since I blew my back plate apart, he will sell me a plate for additional cost. I'll install with new O-rings and then take it to a shop for recharge. Thanks for the advice, everyone.

[Chris4099]

Back to the title, I wonder which one is the best. What reading I have done says the SD510 is stronger but Hervey is selling the SD508.

When I switched to the 508, I did notice a slight drop in performance at idle. But with the small cabin, it wasn't an issue even on hot days. However, you get that and the low current fans and you'll eliminate the kick you feel when it cycles. I have no regrets getting it!

[stevedmc]

When I switched to the 508, I did notice a slight drop in performance at idle. But with the small cabin, it wasn't an issue even on hot days. However, you get that and the low current fans and you'll eliminate the kick you feel when it cycles. I have no regrets getting it!

Do you mean AC performance or engine performance?

[Chris4099]

AC performance. It wasn't as cold at idle (both original and the 508 were charged with R-134a). Still kept the cabin cool though and also no difference when driving at speed. I was fine with that and I like how smooth it is and how it doesn't cause any noticeable stuttering when cycling. If it wasn't for the added light I installed on the fan circuit, I would have no idea when it was cycling.