If you’ve noticed your chainsaw leaving oil spots under the casing or dripping from the bottom when stored, you’re not alone. Oil leaks are one of the most common issues for both professional arborists and home users. The good news? In most cases, it’s nothing serious and can be fixed easily once you know the cause.
Let’s look at the main reasons your chainsaw might be leaking oil and how to stop it.
1. Residual Chain Oil After Use
Most chainsaws automatically release bar and chain oil to lubricate the cutting chain. After use, a small amount of oil often remains in the oiler line or the oil pump housing, and it can slowly seep out when the saw is stored.
What to do:
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Wipe down the bar and casing after use.
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Store your saw on absorbent cloth or cardboard.
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Keep it level, not on its side, to prevent pooling.
This is the most common reason, and completely normal!
2. A Damaged or Loose Oil Line
Your chainsaw’s oil travels through a flexible rubber or plastic line. Over time, vibration, heat, and residue buildup can cause it to crack or loosen, leading to leaks underneath.
Check for:
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Oil collecting near the clutch or bar mount.
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Cracked or hardened hoses.
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Loose connections on the oil tank outlet.
Solution:
Replace the oil line or refit it securely. Most are inexpensive and easy to replace at home with a screwdriver set.
3. Faulty Oil Pump
The oil pump regulates flow to the chain. A worn or clogged pump can cause too much oil to flow through, or for oil to leak even when the chainsaw isn’t running.
Fix:
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Clean the pump and oil port using a small brush and solvent.
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If the issue persists, consider replacing the pump.
Rotatech’s premium-grade oils help prevent pump clogging thanks to their cleaner burn and smoother flow, reducing wear on internal components.
4. Overfilled Oil Tank
Sometimes it’s as simple as overfilling. When the tank is too full, heat and vibration cause expansion, and oil seeps through the vent hole or seals.
Solution:
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Fill the oil tank to about 80–90% capacity.
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Wipe away any excess around the cap.
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Store your saw with the oil cap facing upwards.
5. Worn Seals or Gaskets
If you’ve ruled out simpler causes, a worn tank seal or gasket might be the culprit. Over time, these rubber components degrade and allow oil to escape through tiny gaps at the base.
Fix:
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Replace the tank gasket or cap seal (most spares are inexpensive).
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Inspect all seals whenever you service your saw.
Prevent Future Leaks with the Right Oil
Using a high-quality oil makes a big difference. Rotatech Chainsaw Oil is designed to:
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Lubricate efficiently without excessive residue.
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Protect seals and pumps from wear.
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Reduce build-up that leads to clogging and leaks.
⭐⭐⭐⭐⭐ “Best chainsaw oil available. Wouldn’t buy anything else - does exactly what’s required. Awesome product, highly recommended.”
— Andy, Verified Customer
Shop Rotatech Chainsaw Oil here.
Final Thoughts
A small oil leak doesn’t mean your chainsaw is failing; it’s often a sign of residual oil, a loose line, or normal expansion.
By keeping your saw clean, using the right oil, and maintaining the seals and lines, you’ll keep it running smoothly for years to come.