My air compressor doesn't like bitter cold

[Doug Hobkirk]

My air compressor runs well when the temperature is in the mid-thirties but it doesn't like bitter cold. With the belt removed, the motor spins freely but the compressor wheel is very hard to turn. I use the compressor to fill tires, blow off dust, and sometimes for a pin nailer - i.e., I don't use it very often.

I don't know anything about this compressor. I bought it used for $35. There is no manual. I cannot find a manufacturer's name (except GE for the motor). The tank is about 9 gallons based on calculations. I replaced the rubber compressor mounts with simpler rubber "washer" mounts, added a structure so I could attach a reel for my long hose, and painted it. It pumps up to a little over a 100 psi. The previous owner had a cup covering the pressure limiter (?), so I continued his practice with a coffee can. I keep the compressor in a lean-to type shed I added to the side of the garage (my workshop). It runs extremely quietly.

I am hoping I can find answers to these questions.


Is this a hopeless cause? Should I just accept that it simply is not capable of running in cold weather?
Is there a practical way to calculate CFM at specific PSI's? (I would like to find if it is capable of running a HVLP paint gun)
It seems slow to build up pressure when it runs - how long should it take to build up to 100 psi?
Should I fill the compressor with oil up to the threaded boss for the top bolt?
What weight oil should I use? (I assume it should be the lightest (lowest number) compressor oil I can find)

Thanks, as always.

[Steve Rozmiarek]

Doug, compressors are notoriously finicky creature when it comes to cold. Yours is by no means the only one that doesn't like it. I had a big Sanborn a while back that wouldn't run under 20. It was a problem because it was in an unheated shop. I think it has to do with the cold changing the tolerances in the cylinder, but not sure on that.

The only cure to it that I know is to put the compressor in where it is warm, then it will work fine. Turbinaire has a guideline chart for cfm on their website that might help you with the hvlp question.

Time to build 100 psi depends on pump size, tank size, power, tide charts, etc... To many variables to simply give you a number.

I don't know the answer to your oil questions. It should be marked somehow.

[Glen Butler]

Even my nearly new Rol-air, will not get going when it is cold. I don't think it is just thick oil, it is almost as if the castings shrink when they are cold and the piston becomes too tight in the cylinder. Your best bet is to move it inside for a bit to let it warm up.

[Rick Fisher]

I have an Oil heater.. looks like a radiator in my garage/ shop..

I am also up in Canada.. lol..

That simple oil heater keeps the shop warm .. I leave it on the lowest setting, 24/7..

Of course, electricity is really cheap in Canada..

Anyway.. Compressors are all notorious for not liking cold. Point a fan heater at the pump for 1/2 an hour, it will fire up just fine..

[Fred Preston]

my portable rol-air is the same way. I set a halogen light aimed at the oil reservoir for half an hour or so and it fires right up. I have tried thinner oil. no help.

[gordon mosher]

You could try opening the drian cock at the bottom of the air tank to let all the air out of the tank before starting it. This will take the pressure off the cylinder and let the compressor start better. Leave the drian cock open for a couple minutes with the compressor running before you shut it.

[Jason White]

If it's oil-lubed, just flip the power on and off a few times until it spins.

Jason



My air compressor runs well when the temperature is in the mid-thirties but it doesn't like bitter cold. With the belt removed, the motor spins freely but the compressor wheel is very hard to turn. I use the compressor to fill tires, blow off dust, and sometimes for a pin nailer - i.e., I don't use it very often.

I don't know anything about this compressor. I bought it used for $35. There is no manual. I cannot find a manufacturer's name (except GE for the motor). The tank is about 9 gallons based on calculations. I replaced the rubber compressor mounts with simpler rubber "washer" mounts, added a structure so I could attach a reel for my long hose, and painted it. It pumps up to a little over a 100 psi. The previous owner had a cup covering the pressure limiter (?), so I continued his practice with a coffee can. I keep the compressor in a lean-to type shed I added to the side of the garage (my workshop). It runs extremely quietly.

I am hoping I can find answers to these questions.


Is this a hopeless cause? Should I just accept that it simply is not capable of running in cold weather?
Is there a practical way to calculate CFM at specific PSI's? (I would like to find if it is capable of running a HVLP paint gun)
It seems slow to build up pressure when it runs - how long should it take to build up to 100 psi?
Should I fill the compressor with oil up to the threaded boss for the top bolt?
What weight oil should I use? (I assume it should be the lightest (lowest number) compressor oil I can find)

Thanks, as always.