Compressor oil?

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Aug 4, 2020
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I need advice on air compressor oil. I'm embarrassed to say I've never had a compressor until recently. I have plans to purchase my own in the future, but until then a friend of mine is loaning me his for free because he has no room for it for at least a year or two. I know almost nothing about it except that it is a Speedaire 3Z492. I'm fairly confident it's been neglected, because he provided a quart of oil that's so old you can't make out a single letter on what's left of the label. I can't even tell what brand or grade it is. It's a cross between a lime green and yellow colored bottle. I want to change the oil considering it's a pretty old unit. On the "maintenance instructions" label, it clearly states the following:

Daily - Check for proper oil level.
Monthly - Inspect oil for contamination and change if necessary.
Every 3 months - Change oil.

I did some searching online as well as on this forum, and saw nothing but mixed answers. Answers included "use ND SAE30" to "use literally anything" as well as "0W-30" and many others.

Based on what I read, the 'correct' answer is to use a proper "air compressor oil" but that stuff is really expensive. The next 'correct' answer is to use a ND SAE30 (somewhat rare but usually cheap). Beyond that, use any XW-30 and call it a day. Also, there was no consensus on conventional or synthetic.

What do the experts here have to say?
 
Use a standard 30 ND oil of your choice. That's the typical WW Grainger house brand with an Indian pump

In this application ( steady state, normally inside and no combustion), synthetic or dino has no distinctive advantage ( or disadvantage)
 
That service intervals are a little overkill IMO.

Straight 30 ND will work or if you want to be fancy, Ingersoll Rand has a synthetic that’s just under $10 a quart.

Even though the general census is to use ND oils, many here have used 0wxx PCMO’s issue free. I assume it’s because of the cold flow properties.. That said, you might as well get a synthetic like the mentioned IR or even an Amsoil offering. I guess if it’s a cheaper and/ or secondary compressor, go for it.
 
You want to use a non-detergent 30 or oil labeled for compressors. Synthetic or conventional is fine. The use of multi weight automotive oils with detergent will cause foaming and will keep dirt and whatever other contaminants suspended in the oil instead of dropping to the sump. Just check oil levels.. filters and follow manufacture maintenance schedule.
 
I need advice on air compressor oil. I'm embarrassed to say I've never had a compressor until recently. I have plans to purchase my own in the future, but until then a friend of mine is loaning me his for free because he has no room for it for at least a year or two. I know almost nothing about it except that it is a Speedaire 3Z492. I'm fairly confident it's been neglected, because he provided a quart of oil that's so old you can't make out a single letter on what's left of the label. I can't even tell what brand or grade it is. It's a cross between a lime green and yellow colored bottle. I want to change the oil considering it's a pretty old unit. On the "maintenance instructions" label, it clearly states the following:

Daily - Check for proper oil level.
Monthly - Inspect oil for contamination and change if necessary.
Every 3 months - Change oil.

I did some searching online as well as on this forum, and saw nothing but mixed answers. Answers included "use ND SAE30" to "use literally anything" as well as "0W-30" and many others.

Based on what I read, the 'correct' answer is to use a proper "air compressor oil" but that stuff is really expensive. The next 'correct' answer is to use a ND SAE30 (somewhat rare but usually cheap). Beyond that, use any XW-30 and call it a day. Also, there was no consensus on conventional or synthetic.

What do the experts here have to say?
If the compressor will be stored indoors above freezing temperatures conventional non-detergent 30 will be fine check Walmart or a tractor supply. https://www.tractorsupply.com/tsc/p...rgent-sae-30-motor-oil-6-1-quart?cm_vc=-10005
 
Even though the general census is to use ND oils, many here have used 0wxx PCMO’s issue free. I assume it’s because of the cold flow properties..

Sure they do and all beliefs to the contrary- it wont explode because someone used a multi grade oil. Only in the rarest of situations would there be a noticeable difference.

The reason they are 'preferred" (recommended) is that all MG oils use thinner base stocks for the "W" that thicken under use.

Straight weight is just that.

In a recip ( difference being a steady state operation in terms of RPM and HP when in use) that "all things equal" the straight grade will last longer under the forces. If you don't run the compressor 24/7 even that "difference" is going to be negligible.

That's based on literally tens of thousands of O/A's over thousands of compressors of all types over decades. Most of these claims are long on the hat but short on cattle.

Its all about your pocketbook.
 
I use non detergent SAE 20 that I have a few quarts leftover. Some small parts stores near me still have this oil.
 
I use non detergent SAE 20 that I have a few quarts leftover. Some small parts stores near me still have this oil.
Reminds me of 3in1 blue bottle. I’m sure the sae 20 you have doesn’t have the 3in1 smell lol
 
Straight 30 ND will work or if you want to be fancy, Ingersoll Rand has a synthetic that’s just under $10 a quart.

Where did you get Ingersoll Rand synthetic for under $10 a quart?
 
I just hooked up an Ingersoll Rand after 12 years. It came with an extra quart and that’s what I used. I have found compressor oil at any big box farm/hardware store, i.e. Tractor Supply, Rural King, Blain’s
 
The use of multi weight automotive oils with detergent will cause foaming and will keep dirt and whatever other contaminants suspended in the oil instead of dropping to the sump.
I may be showing my ignorance here, but why would it foam if it's not overfilled? And if it's running, nothing would "drop to the sump" until it shuts off. But then once it turns on again, it's right back in circulation. Right?
 
If the compressor will be stored indoors above freezing temperatures conventional non-detergent 30 will be fine check Walmart or a tractor supply. https://www.tractorsupply.com/tsc/p...rgent-sae-30-motor-oil-6-1-quart?cm_vc=-10005
I guess I should have mentioned that it will be indoors, but will be exposed to temperature extremes because even though I do have dedicated central heat and air in my shop, I'm not out there every day. Sometimes there's a few days or even a week in between use. So both hot (105F max) and cold (-5F max) temps will be a factor. This has me leaning toward a XW-30 for cold flow, even though it's against the popular advice of SAE30 ND.
 
Sure they do and all beliefs to the contrary- it wont explode because someone used a multi grade oil. Only in the rarest of situations would there be a noticeable difference.

The reason they are 'preferred" (recommended) is that all MG oils use thinner base stocks for the "W" that thicken under use.

Straight weight is just that.

In a recip ( difference being a steady state operation in terms of RPM and HP when in use) that "all things equal" the straight grade will last longer under the forces. If you don't run the compressor 24/7 even that "difference" is going to be negligible.

That's based on literally tens of thousands of O/A's over thousands of compressors of all types over decades. Most of these claims are long on the hat but short on cattle.

Its all about your pocketbook.
If this is true, then the last sentence is telling me to use my nearly endless stock of PCMO I get for pennies on the dollar instead of going out to buy oil at retail prices. It also has an advantage in the cold...
 
I guess I should have mentioned that it will be indoors, but will be exposed to temperature extremes because even though I do have dedicated central heat and air in my shop, I'm not out there every day. Sometimes there's a few days or even a week in between use. So both hot (105F max) and cold (-5F max) temps will be a factor. This has me leaning toward a XW-30 for cold flow, even though it's against the popular advice of SAE30 ND.
Don’t do it. Just spend the money on a synthetic compressor oil. I work in maintenance and when we service the compressors for the hvac systems around the district not one mechanic I’ve worked with ever put a multi weight automotive oil in a compressor crank case.
 
I may be showing my ignorance here, but why would it foam if it's not overfilled? And if it's running, nothing would "drop to the sump" until it shuts off. But then once it turns on again, it's right back in circulation. Right?
I’m not a scientist just knowledge of working with good mechanics and asking questions. The idea is in non detergent oils dirt contaminants metal shavings etc are not suspended in the oil. due to the detergents and dispersants that are in automotive oils all the mentioned is suspended in the oil which would be put through an oil filter eventually. If that makes any sense lol.
 
One oil that everyone here is overlooking is Hydraulic oil. Specifically, I like 46 AW available at tractor supply and many other places. Anti foam additives, low or NO detergents, good all weather viscosity, straight weight, and anti wear.
I've used it in a Sears piston type compressor for years without issue. In fact it was one of the oils recommended for compressors in my Valvoline Application Chart, which is now long gone.
 
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If this is true, then the last sentence is telling me to use my nearly endless stock of PCMO I get for pennies on the dollar instead of going out to buy oil at retail prices. It also has an advantage in the cold...

It is true and you should and I can assure you there will be no detriment to your equipment from it.
 
I may be showing my ignorance here, but why would it foam if it's not overfilled? And if it's running, nothing would "drop to the sump" until it shuts off. But then once it turns on again, it's right back in circulation. Right?

1- When contamination drops in the sump, it stays there ( out of circulation) which is why ND oil is recommended because detergents are suspension agents. ( detergents don't clean anything, they are not soaps or solvents- they suspend)

2- AF agents are used because some designs ( not just compressors) have cranks or other protrusions that punch the fluid driving air, others have gears doing it, some have lube paddles/spurs and a host of other things that aerate oil causing foam. Some machines don't so select the additives according to the need.
 
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