How to Oil Impact Wrench

By Richard S. Clark | Last Updated: February 18, 2022

Oiling an impact wrench is an excellent way to preserving it. Any tool that has movable parts needs frequent servicing. Failure to do so, these parts will wear out and eventually rendering the product unusable. They also tend to become tight and rusty whenever they lack oil.

In most cases, when you buy a new one, they come oiled. It is upon the user to do the frequent maintenance for a smooth performance.

In this article, I will demonstrate the step by step procedure of oiling an impact wrench. I shall also mention the frequency of doing so.

What do you need to oil in an impact wrench?

In most cases, two parts need frequent oiling in an impact wrench. They are:

  1. The air motor, and
  2. The rotating hammer.

As you put it to constant use, it gets old, and the oil inside evaporates because of heat and contamination. It makes the tool not to perform optimally. When such happens, you will begin to hear irritating sounds from the wrench, coupled with poor performance.

To solve such problems, you must oil your wrench frequently and at regular intervals, if possible.

Tools that you require for oiling

  1. Motor oil.
  2. An align key.
  3. A compressed air supply.
  4. An old wrench for cleaning and oiling.
  5. Petrol for cleaning the parts.

How to oil an impact wrench

The procedure

  • Take off the oil plug nut.

Use a 4mm align key to remove the oil plug nut that is over the oil port.

  • Insert the motor oil.

Put approximately 30ml of motor oil inside the oil port to lubricate the impact wrench rotating hammer. You can use a syringe to inject the lubricant.

  • Insert the air tool oil.

Count about seven droplets of air tool inside the air compartment. It will lubricate both the vanes and air motor of the impact wrench.

  • Run the impact wrench for about a minute.

It will cause the lubricating oil to distribute evenly in the hammer and the air assembly. If you use it without running it first, then whole parts will not get lubrication, and hence may waste away.

  • Drain out the excess oil.

If you do not do so, it will leak, especially when the wrench is in use. Open the oil plug to drain the excess oil into a container.

  • Cover with the rubber jacket

You will need to put it back as it was initially. You had removed it from its place when you were cleaning before oiling! Place it over the air impact wrench, and your tool is now ready for use. It even looks somewhat new now! You can now use it to remove and put back the nuts and bolts.

How often should I oil my impact wrench?

Do it frequently. However, the more you use it, the more the oil dries up. So the amount of work it undertakes will dictate the frequency of servicing it.

If you are not using it quite often, you should make it a practice to oil it once or twice in two months. That is because the oil gets dirty and dry even when not in use.

Can I use any form of oil for this process?

Yes, you can use any lubricant to oil the tool. You should, however, be wary of non-genuine products in the market. I would say that you should follow the manufacturer’s recommendations on the type of oil to use. Alternatively, you can consult your mechanic on the best product to use in your tool.

Over time, you will also get to understand the best products for your impact wrench.

Why should I clean the wrench before oiling it?

When you use the wrench, the oil inside it gets dirty and contaminated. Its efficiency and effectiveness are also reduced. Small chippings also get into the lubricants and hence making it lose power. That is why you have to drain the old oil and clean it with petrol before adding some new one.

If you mix the new and old oil, the dirt will remain in the compartment, and it will finally clog the wrench. It will eventually cause it to break down or even damage the movable parts.

When cleaning, you should pay close attention to the internal parts. That is the point where a lot of debris settles when it breaks loose from the moveable parts!

Which part should you start oiling first?

It does not matter which part you begin from, as you can start with the hammer mechanism and end with the air motor. Alternatively, you can start from the opposite and end with the previous.


An impact wrench needs frequent oiling. It has two parts that need this service at given intervals. Therefore you should make it a routine to do the task. Before oiling, you should first clean it, and especially the interior parts. It helps to remove debris and other dirt. Always use the oil that is recommended by the manufacturer so that you can get quality output from your wrench.

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