Adjusting moisture draining valve on air compressor tank

How often do you need to replace your shop air compressor?

While cleaning my shop, I happened to look at the tag on my air compressor, and its construction date was 1994. I've always drained it after use, and there are no outward signs of rust, but I'm a little concerned about its age. Are there any rule of thumb type thoughts on when a air compressor should be replaced? – Michele Miller

Chris Marshall: I don't think there are general guidelines about when an air compressor should be retired. I've never read or been informed about any, at any rate. If the condensation in the tank doesn't have flakes of rust in it, the air seals are still holding and the motor is running strong, I'd just keep right on using it. An air compressor kept indoors in a hobbyist's shop is going to last much longer than one in a pro shop, on daily jobsites or in an industrial situation, especially if you are taking good care of it.

Speaking of which, you are doing the right thing by draining the tank after you use it. Keeping the cast-iron surfaces inside the tank dry will just prolong its life. And, depressurizing it when not in use can only help the air seals, too. When the day comes that the tank develops a pinhole leak or the motor dies, then you'll know it's time to start shopping for a new one. Until then, no worries.

Tim Inman: 1994? Your compressor is almost brand-new. I bought my shop compressor in 1974, and it is still going just as strong as when it was new. Now, granted, I have put in a new set of reed valves and I do change the compressor oil every year (I use full synthetic motor oil). I also drain the condensed water from the tank about two or three times a year, too. It is running on the same belt that it came with. So, all in all, it works like new.

Our demo shop in Wisconsin ran on a WW II compressor. The shipping building was also running a very old compressor. It might have been pre-WW II. We did try to keep them serviced, but they came with old warehouse buildings we purchased and I'm guessing they never had much TLC in some decades before we showed up.

All to say, take care of your compressor, and it will take care of you for many years to come. Let it run dry (of oil), and with amazing speed, you'll be out shopping for a new one.