How often to change oil in compressor?

[blueman]

I have a Harbor Freight 8 gallon 120PSI compressor that has paid for itself half a dozen times over just in fees saved for blowing out my sprinkler system.

I use it intensely once a year for sprinkler blowout (9 zones x 6 repeats per zone) and about 1-2 times per month for light project use (usually just fills the tank a couple of times).

The compressor takes about 25oz of 30 weight non-detergent oil. The oil level seems to remain pretty steady in the window.

- Should the oil be replaced at regular intervals?

- If so, is there a good general rule of thumb for how freqently to replace (either in terms of calendar time or usage)?

- Also the manual says use "30 weight non-detergent oil". Can I use the oil so labeled at an auto parts store or do I still need to buy "special" compressor oil of that weight?

Thanks

[Max]

I change mine (30 gallon Craftsman) once a year but I use it much more than you seem to. Air compressor oil isn't that expensive and you don't need much so why not use it. I should mention that I live in a dry climate (El Paso, TX) and as a consequence don't get much moisture in the tank (or the oil)

Max

[salty]

Especially with those inexpensive compressors, the first oil change after about 10 hours of use is critical. Afte that, once a year should be fine.

[Ed Pawlowski]

"blueman" wrote

At work we change oil about every 1200 to 1500 hours. I don't think you are close to that. Compressors don't get contamination the way internal combustion engines do so the oil will last much longer. You don't need special oil as regular 30 weight is recommended by the factory.

[Joe AutoDrill]

Yes. Synthetic is even better and still less expensive than the stuff they will sell you.

[dpb]

Ed Pawlowski wrote: ...

OP does _NOT_ want "regular" automotive 30W; definitely need a non-detergent oil.

--

[Robatoy]

I personally witnessed: Run the engine up to temperature on a wheel-driven dyno take a sample and print. Without delay, change to synthetic. Run the engine up to temperature on same dyno, half hour later, sample and print. It was a 1996 Safari van, with a 4.3l with 240,000+ miles of Michigan driving on it. No idea who owned it, I was next door buying some parts and I was, as usual, poking my nose around the corner to see what these crazies were up to that day. (WHO can stay away from a speed shop?)

133 HP to 137 HP. I doubt it would show up on the quarter mile time, but hey, I was surprised.

No regular oil for these guys:

I digress.

Over the years, I always changed the oil on any of my compressors every 6 months. Why not? It's not that those crank-cases hold gallons of the stuff...and yes, synthetic for the last 10+ years.

[Larry W]

In article , Robatoy wrote: ...snipped...>

133 HP to 137 HP.

There may well be something to that, but it would not be unusual to have a 4hp variation between runs even if NOTHING changed.

[Robatoy]

On tech offered the idea that less restriction in the new oil filter could even make a 4 HP bump.

[Ed Pawlowski]

"Larry W" wrote

Back in the '70s I used to do a fair amount of tinkering with model airplane and race car engines. Synthetics were fairly new at the time and we experimented. It was common to pick up a few thousand rpm and use less oil in the mix. Made me a believer, as did the ME that I did this stuff with.