Automotive Air Conditioning Information Forum

I have a Classic Auto Air system in my Corvette. The system cools fine but the Sanden SD7H15 compressor makes a growling noise but only between 1500-1700 rpms. It is quiet at all other rpms. It seems to be worse (louder) after operating for 15-20 minutes when everything is heated up. I even avoid turning on the system except when it really hot outiside. I've checked the usual suspects, compressor mount, hoses rubbing and all's good. Pressures are 10-30 low side and 190-225 high side at 80F which according to CAA are within normal range. Vent temps typically 38-45F. Any ideas why it's only noisy at a specific rpm range? If the compressor was bad, wouldn't it be noisy all the time?

Perplexed.....

Mac

My experience with that compressor was not great. It is noisy because of the gears inside of it and it lacked displacement and BTU capacity compared to a GM compressor.

You can try an inline muffler on your suction side. This model is much better (noise) than the SD508 series. Overall, they are good compressors, IMO. Is it a true Sanden or an imported knock-off?

Thanks for the reply. Where does one get a suction line muffler? Compressor has Sanden label on it but there are no Sanden markings on the compressor. Label says to use SP 15 oil. I think I bought it from Retroair.

Mac