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What To Do if a Stihl Chainsaw Uses Too Much Bar Oil

What To Do if a Stihl Chainsaw Uses Too Much Bar Oil

Chainsaws require bar oil to prevent overheating and damage during use, but it can be annoying (and expensive) if the chainsaw uses more bar oil than it should.

If your Stihl chainsaw uses too much bar oil, check to see if oil leaks from the oil cap. The toolless Stihl oil caps tend to leak frequently. Therefore, replace the faulty toolless oil cap with another one, and keep the new cap clean to prevent future leakage.

In the rest of this article, I’ll explain the most common causes of a Stihl chainsaw using too much bar oil. I’ll also discuss how to fix these problems so you can avoid using too much oil. Keep reading to learn more. 

Stihl Chainsaw Using Too Much Bar Oil? Causes and Solutions

If your Stihl chainsaw uses too much bar oil, it’s usually due to one of two causes: 

  • An oil leak
  • You are storing your chainsaw in a place exposed to extreme temperatures 

I’ll discuss these causes in more detail below: 

Your Stihl Chainsaw Has an Oil Leak

An oil leak can occur because of the patented toolless oil cap. To fix the problem, replace the oil cap with a new one and clean it regularly.  

You can check to see if an oil leak is the cause of your woes by placing your Stihl chainsaw on a piece of cardboard or a paper towel. Leave the chainsaw for a few minutes. When you return, check the area on the cardboard or paper towel underneath the oil cap. You’re likely to see oil traces there, indicating a leak.

If you’re still unsure, run your fingertip underneath the oil cap to see if you feel oil there. If you do, it’s likely that the oil cap is the problem.

Unfortunately, it is relatively common for Stihl chainsaw owners to notice bar oil leaks because of Stihl-patented fuel and oil tank caps. These caps are supposedly designed to be easier to open and close by hand (source). 

However, instead of making life easier for chainsaw users, many experience more oil leaks and bar oil usage because of these caps. 

The caps usually work for the first few months of use, but they become defective, especially for people who use their chainsaws frequently. 

One way to prevent the oil cap from getting defective and allowing leaks is to clean it frequently. Keeping the cap clean will prevent it from getting damaged, scratched, and ineffective due to dirt and debris exposure. However, normal use and wear and tear eventually lead to the oil cap’s mechanical parts not working as they should and not tightening enough to keep the oil inside.  

To solve this problem, I recommend replacing the oil cap. I suggest using the Hipa HT101 Fuel Cap (link to Amazon). This oil cap is compatible with most Stihl chainsaws, and Hipa has a good reputation within the industry for using high-quality materials.  

To install a new cap, line up the notches on the cap with the notches on the oil tank. The cap can only go in one way, so if you rush the process and don’t fit it properly, you’ll still leak bar oil.   

Your Chainsaw Is Exposed to Extreme Temperatures

Another possible reason a Stihl chainsaw might go through bar oil quickly is if you store it in an area exposed to extreme temperature changes. Stihl chainsaws have a special valve oil tank breathing system designed to keep the chainsaw from overheating and causing damage (source). 

However, this system also allows oil to leak from the tank through the oil pump if the exterior temperature changes too much. 

If you live in an area where the temperature varies greatly from day to night, I recommend keeping your Stihl chainsaw inside, where it isn’t exposed to this change in temperature and air pressure. Storing your chainsaw at a more consistent temperature prevents the oil tank’s air and oil from expanding to equalize the air pressure, reducing the chances of leakage when the temperature changes again.   

How Much Bar Oil Should a Chainsaw Use? 

You may think that you’re going through too much bar oil, but it’s important to have a good grasp on how much your saw should be using before you assume there’s a problem. 

Most gas chainsaws have a fuel tank that uses a proportionate amount of bar and chain oil (i.e., there’s one bar and chain oil tank for every fuel tank) (source). Therefore, whenever you fill up your chainsaw’s fuel tank, you should also check how much bar oil there is left.

To fill up your saw’s bar oil, follow these steps: 

  1. Put your Stihl chainsaw on a flat, smooth surface. I recommend replacing the bar oil outside, so you don’t ruin anything if you accidentally spill.  
  2. Add chain lubricant before replacing the bar oil. Most Stihl chainsaws have an automatic filling system, so the tank will stop filling with chain lubricant once it’s full. 
  3. Remove the bar oil cap. Most Stihl chainsaws use a toolless cap, so you won’t need additional tools for this step. 
  4. Use a funnel to fill the bar oil reservoir. 
  5. Put the cap back on. Ensure that the cap is tight, but don’t try to force it. If it stops twisting easily, there’s no reason to force it beyond that point.  
  6. If you see too much oil on the saw, wipe it clean. 

I recommend using the Stihl Platinum Bar and Chain Lubricant (link to Amazon). I like that this oil is from the original equipment manufacturer and is designed for heavy-duty cutting. I also appreciate that the tackiness helps the oil stay on the chain, even when using the saw at high cutting speeds.  

For more information, check out my guide on how often your chainsaw needs bar oil. It discusses potential signs of low bar oil, so you can fill up the oil reservoir before the chainsaw gets dry and causes problems.

Final Thoughts 

Unfortunately, Stihl chainsaws have a reputation for using too much bar oil because their toolless oil caps get damaged and defective too quickly and can’t hold the oil in the tank. When this happens, the oil leaks out, and users go through more oil than they should. 

Another potential cause of oil leakage is too many extreme changes in temperature. You can solve these problems by replacing the oil cap or storing your chainsaw inside.   

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