Tools, Sharpening and Power Machinery - oil for old compressor pump

i have an old air compressor that quit on me last winter . i had the motor checked out,it was ok. been using 30 wt oit in pump for years.could that actually have finally have finally caused it to stop during the winter. i living in illinois. i drained all the oil out of the pump . all i can seem to find is 20 wt. i had non-detergent in it.thats what it has always had in it. should i try to find a 10 wt or do they make it or what is your recommendation. the air compressor has always worked good until it just stopped. every time i tried to plug in it though a breaker. then when i unhooked the pump and plugged in the motor it was fine. whats your thoughts?

Can you turn the pump by hand with the belt off. Both ways? Could be bad starter switch on the motor. Check it. Oil Id stay with #30 non detergent.

ED ;)

Roeboat109,

30 weight non-detergent oil is the correct oil to use for your compressor.
The proper thing to do is in cold weather, use something to warm the head to keep the oil viscous.
The problem is that they do not make a multi-viscosity oil in a non-detergent type which is what your compressor needs.

If it used to start in the cold with 30w and doesn't now,there could have been damage done to the pump from a lack of lubrication or the motor from starting against too hard a load.
I use air compressors in sub-zero temps and also have my shop unit outdoors in an unheated shelter.
I use a 50 watt magnet heater stuck to the crankcase and it starts effortlessly at 30 below.

To check the pump you should change the oil then disconnect the discharge line from the head and see how it spins without a load.
A damaged or plugged check valve could cause the symptoms you are experiencing.
Also, how was the motor checked out?
If it was just plugged in on a bench it may not show a problem with the starting switch as Ed suggested or the capacitor.

i've used 10w30 and not hurt one, wasn't a full time unit