It can be quite a daunting task trying to figure out how to change your Harbor Freight compressor oil, how much to use and what is correct Harbor Freight oil to use right? Well, fear no more, I will answer all these questions in relation to Harbor Freight compressor oil for you.

Table of Contents

What kind of Oil goes in a Harbor Freight Compressor?

It is extremely important to refer to your compressor manual before purchasing Harbor Freight oil for your Harbor Freight compressor. We have numerous Harbor Freight compressor manuals available on our brand page so please visit here first!

The manual will tell you what Harbor Freight oil is compatible with your air compressor, if you cannot locate your manual, please contact Harbor Freight directly or visit their website to download a manual for your compressor.

Harbor Freight Compressor Oils

Though Harbor Freight do not appear to directly produce their own compressor oil, they sell Central Pneumatic 32 Oz compressor oil directly on their website which indicates it is their recommended Harbor Freight compressor oil for their compressors. Though please check your manual or contact them directly to confirm this before using it!

This high performance air compressor oil is designed to maximize performance and does not foam. The compressor oil eliminates the varnish, sludge and carbon deposits that wear down your compressor.

The oil is also readily available on Amazon and can be purchased below!

Alternative Compressor Oils Available on Amazon

A few alternatives to the Harbor Freight compressor oils are produced by Mobil. Again, it is very important to ensure the oil is compatible with your air compressor before putting it into the system, so please check first!

The first is the Mobil 101016 Rarus which is suitable for reciprocating air compressors whether they’re single or multistage. This oil lubricant boasts excellent water separability, protection against rust and corrosion, long life for extended oil drain and provides your compressor with very clean air valves.

The second is the Mobil 100870, boasting similar benefits as the previous oil but potential to work with reciprocating, rotary screw and rotary vane compressors.

How Much Harbor Freight Oil to Use in a Harbor Freight Compressor?

It’s very difficult to determine how much Harbor Freight oil a specific compressor pump requires without having the manual.

If you cannot find your specific manual, I would recommend that you contact Harbor Freight directly or conduct a simple internet search on the specifications of your Harbor Freight compressor and its model!

Obtaining the manual will help you with the exact amount of oil lubricant that you should put into your Harbor Freight compressor.

It is hard to gauge the exact number on how much you need, so instead I can give you tips on how to check the Harbor Freight oil amount inside your compressor and afterwards I’ll describe how you can change it.

Harbor Freight Oil Sight Glass

The image below shows the Harbor Freight oil at the desirable level inside the sight glass (halfway up the red dot). This sight glass allows you to look inside the compressor pump and check how much Harbor Freight oil is there.

Sight Glass
Typical Air Compressor Oil Sight Glass

Harbor Freight Oil Dipstick

Air compressor pumps don’t always have a sight glass, and so they use a dipstick. They can commonly be found as part of the Harbor Freight oil fill tube cap and extend down into the sump and Harbor Freight oil.

You should take the dipstick out and give it a wipe before dipping it back into the sump and checking the marking on it which will tell you the Harbor Freight oil level.

Typical oil fill dipstick
Typical oil fill dipstick

Alternative Method for Checking Harbor Freight Oil

An alternative method if you don’t have a sight glass or dip-stick is using a sight glass or dipstick is draining the Harbor Freight oil from the tank into a reservoir.

How to Drain Harbor Freight Oil from the Sump

Locate your Harbor Freight oil drain which will be a plug located underneath the compressor pump housing. Drain the Harbor Freight oil into a reservoir which will help you gauge the correct amount of Harbor Freight oil in your sump so you can put the same back in.

Be careful when draining the Harbor Freight incase you get oil spill. A good idea may be laying something out on the floor below the compressor.

How to Change Harbor Freight Compressor Oil

Changing Harbor Freight oil on each model of compressor will certainly be slightly different from one to another.

Ask yourself if your compressor definitely oil lubricated and make sure you have an answer to this first. Check the model manual or contact Harbor Freight directly.

Changing Harbor Freight Compressor Oil Process

After draining the Harbor Freight oil from the compressor following the steps just described, you should fit the plug back into the bottom of the sump and securely tighten it.

At the top of the Harbor Freight oil sump there should be a port into which you can add the new Harbor Freight oil. It’s difficult to be more specific than that as I do not know your model and they can vary slightly.

Add about as much Harbor Freight oil as you’ve removed or gauge it using the sight glass or dipstick. Be cautious as you do not want to overfill the sump.

Note: when filling the compressor with Harbor Freight oil, do not fill the air intake on the pump.

Summary

The above methodology is simplified for ease into the following steps:

  1. Check Harbor Freight oil level
  2. Locate plug beneath sump
  3. Drain Harbor Freight oil into reservoir
  4. Tighten plug back into sump
  5. Locate Harbor Freight oil port
  6. Replenish the compressor with the same amount of Harbor Freight oil as removed (do not overfill)

Without having access to every air compressor model manual, and assuming that the manual tells the reader what the Harbor Freight oil volume is, there is no way to be anything but vague when providing advice about changing Harbor Freight compressor oil.

Harbor Freight Compressor Oil FAQs (Frequently Asked Questions)

OIL SPILLING OUT OF HARBOR FREIGHT AIR COMPRESSOR

by Bob
(Hobe Sound, FL)

The plastic combo oil filler/dipstick with crankcase breather on my little 2.5 gallon Harbor Freight compressor was cracked and falling apart.

I put a collar and epoxied a reinforcing cap on it, then I re-drilled a new breather hole to intersect with the old.

Central Pneumatic 3 gallon air compressor
Central Pneumatic 3 gallon air compressor

I ran the compressor, later noticing a growing puddle of oil underneath.

I can’t see where from just yet. In re-examining the repaired cap (since that was the last thing “fixed”) it seems possible that the new breather hole was inadequate or blocked by drill swarf. If that is the case is it likely that oil leak came from the crankcase oil seals due to a build up of crankcase pressure?

If so, are these seals easily replaced or should I just get myself a new $89.00 compressor?

This compressor has not seen much use and should have lots of life left – normally.

Thanks.

_______________________
Bob, “easy” is in the eye of the doer. What’s easy for you might be hard for another, and since I don’t know your capabilities, I don’t know if re & re seals would be easy for you or not.

Certainly time consuming, and you will make quite a mess as you pull the sump apart to find, and replace seals.

Your premise about seals may not be correct. While there is some migration of air into the sump past a leaking cylinder seal, I understand that the vent hole is there to allow outside air into the oil sump to replace oil that has been “used” and stopping a vacuum from being formed.

You will have a time trying to get Harbor Freight air compressor parts too.

However, if I had the time, and the workshop, then I would certainly tear it down if for no other reason that to see what’s what.

Odd that the oil fill dipstick cap cracked on an air compressor with so little use as yours did???

$89.00 compressor, when we buy one of these, we get exactly the value we paid for.

I could not find any compressor of 2.5 gallon tank size, though I did find a 3 gallon shown in the photo. For what it’s worth, in early 2019 this one’s selling for $60.


If you have any questions about Harbor Freight compressor oil, changing it, which to use and how to use it then please leave a comment below with photos if applicable to help others respond to you!