Another Air Compressor oil question

[Fatstrat]

I just bought the 10 gallon oil type air compressor from the Harbor Freight catalog. The manuel says to use "30W Compressor oil".
Is there a difference between "compressor oil" and Motor oil?
If not, should I use straight SAE30 or 10w-30 ?
Any advantage/disadvantage to using synthetic? Thanksin advance.

 

[bruce381]

Most " 30wt air commppressor oils" are just (R+O)
rust and oxidation inhibited BUT in small piston compressors a straight wt 30 PCMO is fine.
bruce

 

[Fatstrat]

What is PCMO? I'm not very up on this stuff. I bought a bottle of Wal Mart brand Super Tech Compressor oil. But it doesn't give the oil weight on the bottle. Does anyone know what it is? Will it be OK for my compressor? Thanks

 

[tom slick]

Passenger Car Motor Oil

 

[widman]

Compressor usually require a good oil with Rust & Oxidation additives (R&O), usually non-detergent, with demulsifiying qualities. Motor oils absorb moisture, so are normally discuouaged. So they sould really say ISO 100 compressor oil. Smaller compressors or those in cold climates use ISO 68.
Companies shouldn't really use automotive viscosity terms for industrial oils. But they do.

 

[04SpecV]

I just bought a compressor. It says use 10W30 fully synthetic motor oil.

 

[Fatstrat]

OK, the Wal Mart Super Tech air compressor oil is ISO-100. My compressor needs 30W according to the handbook.
I've noted while searching the net for info that there are other weights of compressors oils.
Is ISO-100 a 30W?
Thanks.

 

[Pablo]

Yes ISO-100 is a mid 30W. Should work fine.

 

[Fatstrat]

Many Thanks!

 

[GeneralEclectic]

Probably too late to help you but the people at HF are *supposed* to hand you two quarts (@ no charge) of the appropriate oil when you buy the compressor. They have it in stock. I think I got Castrol something or other for the one I bought. It's about a 30 weight as others have said, but oddly, it's water-clear.

BTW, make sure you have a heavy enough electrical service. The starting current of those motors is very high and will tax an average 12GA branch circuit. If you're more than 30' from your service panel, I'd recommend a separate branch circuit, 20A breaker, 10GA wiring, 15 or 20A receptacles. Yes, that combination is legal.