The first shop vac I owned was a small one I bought from Harbor Freight.
It was amazing. The first time that water came in under our garage, I could suck it up and send it back outside.
And then the basement flooded. While that required a bigger shop vac and some fans (which I borrowed from a friend), I became a huge fan of the shop vac’s versatility.
If you were to attempt to use 10W-30 oil, the thinner viscosity weight would slip past the piston rings and start to clog the air hoses. You would be spraying little bits of oil every time you use your machine.
The added oil inside of the reciprocating compressor’s piston chamber would also hinder the effectiveness of your compressor.
Unlike an internal combustion engine, the compressor does not heat enough to activate the higher, more protective viscosity of the oil to the manufacturer-recommended 30-weight rating.
Detergents and Corrosion Protection
The differences in detergents are small, but noticeable on machines that are used commercially. Engine oil contains detergents for removing engine carbon build-up and carrying them to the oil filter.
In an air compressor, those detergents can cause tiny metal particles to be carried by the oil and can score the cylinder walls.
Compressor oil has a high amount of anti-corrosive additives but is configured so that contaminants are more likely to rest at the bottom of the crankcase for removal at the next oil change. It is specifically designed for lubricating the ball bearings.
Making An Exception For Cold Weather?
Some manufacturers recommend switching to a 20W oil when working outside in extremely cold weather.
This slightly thinner oil helps to combat the thickening that happens when the temperatures drop below 30 degrees.
That said, some construction foremen have talked about using Mobil 1 5w-30 oil when building in extremely cold northern temperatures.
While using a thinner viscosity oil in low temperatures is way outside the recommendations, these old codgers swear by it.
When Should You Add Oil To Your Air Compressor?
Small, “pancake” compressors and twelve-volt units are oilless. These come factory-sealed and rely on a combination of thin oil and Teflon coatings to protect the compressor.
All others contain oils that you must change. Unless you have an older compressor that leaks oil, it is unlikely that you will need to add oil between changes.
Generally, every 6 months you will want to change the oil. There is a sight bubble on your compressor with a marker line of the correct oil height. If the oil level drops below this marker, consider giving it an oil change.
What Are Air Compressor Oil Characteristics?
Air compressors need an oil that can handle the high heat of compressors. Compared to other machines, the 50 to 85 degrees Fahrenheit that an air compressor reaches, is relatively cool.
Keep plenty of airflow around your compressor to prevent premature wear. If putting the compressor in a closet, make sure there are two vents to allow cross-ventilation of the area.
Most Compressors have a manufacturer recommendation to use a 30W oil. This works for all compressors in areas that are 40 degrees or warmer. In colder areas, consider switching to the lighter 20w oil recommendation.
Compressors oils use anti-rust compounds mixed into them to prolong the life of the pump. You want to avoid motor oils that contain detergent additives that can carry grit around the machine.
Air Compressor Oil Substitutes
There are some other non-detergent oils that might serve as a better option. Instead of using motor oil, consider these alternatives:
Hydraulic fluid is the closest lubrication option. It contains very low detergents and is configured to operate in similar temperatures to that of an air compressor. They also tend to prevent oxidation.
Hydraulic oil works extremely well in air tools for keeping them lubed. Adding a few drops to the inside of the air chuck before each use keeps the tool well-lubed.
Automatic Transmission Fluid
This is another popular consideration, but just as with engine oil, it contains a large number of detergents. In fact, I’ve used ATF to flush engines to get rid of major sludge. I would prefer to use motor oil over transmission fluid if that tells you anything. Stay away.
Engine oil is not recommended for compressors. If you are going to use some, try an SAE 30 oil as the standard 30-weight will provide more consistent protection.
Best Air Compressor Oils
We have an entire article devoted to the best compressor oils. Only use a lubricating oil recommended for pneumatic use.
I am a big fan of the high-quality Powermate Px P018-0084SP Full Synthetic oil. This one is a popular choice among shops that put a high amount of hours on their compressor. It also seems to work well in both high temperature and freezing temperature conditions.
Another option that I like is the Campbell Hausfeld full synthetic oil. This oil is a little more affordable and seems to be just as reliable. I especially notice a lot of home-owners choosing this one for maintaining their machines.
Amsoil also makes a great compressor oil option. I’ve used a lot of their automotive oils and would not hesitate to use their other products if you can find a dealer near you.
If you can’t wait for shipping, most Auto Parts stores will generally have compressor oil on their shelf.
If you were to run 10W-30 synthetic oil in your compressor for a long period of time, it would shorten the compressor life due to the detergents contained in the oil and the thinner viscosity that will clog air hoses and ports.
Your best bet is spending the same amount on manufacturer-recommended, all-weather synthetic compressor oil.
About Zachary Drumm
Hey! My name is Zachary Drumm! This site allows me to try these tools out, piddle around in the garage, and create fresh content for you. When it comes to tools, home improvement, and being a “shade tree mechanic,” you’ve come to the right spot.