Chainsaw Bar Oil Not Flowing? Causes and Fixes

A chain running without oil overheats, dulls quickly and wears the bar and sprocket. Oregon calls a constant supply of oil to the bar, chain and sprocket “vital” — without it, “excessive friction, wear, and damage will occur” (Oregon manual, p. 16). Signs: the chain smokes even when sharp and correctly tensioned, the bar gets very hot, or the rails show blue spots.

Test the oil flow first

STIHL’s check: hold the bar nose over a light background such as a stump or cardboard — without letting the tip touch anything — and run the saw at half throttle. You should see an increasing trace of oil thrown off the chain (STIHL Sharp Advice, p. 10). On a battery saw, run it at moderate speed the same way. If you see oil, the problem is elsewhere (tension, a dull chain, a worn bar). If you don’t, work through the steps below with the saw switched off and the battery removed or spark plug wire disconnected.

1. Oil level and oil type

• Check the level every time you refuel. STIHL and Oregon both say to check or fill the oil tank each time you fill the fuel tank (STIHL Sharp Advice, p. 10, Oregon manual, p. 21).
• Use bar and chain oil. Both makers say not to use used or old engine oil; Oregon says such oils carry acids and grit that shorten the life of the bar and chain.
• Check the oil cap. Clean the cap and its vent, and make sure it seats properly.

2. Bar oil hole and groove

STIHL and Oregon both say to keep the bar’s oil inlet hole and groove clean (STIHL Sharp Advice, pp. 2–3, 10, Oregon manual, p. 88). Packed sawdust and pitch are the usual blockage, especially after a saw has sat unused.

1. Remove the side cover, chain and bar.
2. Clear the oil hole(s) near the bar tail with a thin wire.
3. Scrape the groove clean all the way around, including the nose, with a groove cleaner or a thin flat blade.
4. If the bar has an oil hole on each side, clean both, so the bar oils whichever way it is fitted.

3. The oil outlet on the saw

With the bar off, find where oil leaves the saw body (next to the bar studs) and clean sawdust and gummed oil out of the outlet and the pad around it. Brush or scrape it out rather than pushing debris into the hole.

4. Bar alignment after a replacement

If the problem started with a new bar, check that the bar’s oil hole lines up with the saw’s outlet. A bar with the wrong mount can bolt on and still miss the outlet — see bar mount codes.

5. The oil adjuster

Some saws have an adjustable automatic oiler (STIHL Sharp Advice, p. 10). Your manual shows where the adjuster is and which way increases flow. Make sure it hasn’t been turned to minimum.

6. Cold weather

Ordinary bar oil thickens in the cold. STIHL says at extremely low temperatures normal chain oil can become too thick to flow; use a winter-grade bar and chain oil and increase the oil flow (STIHL Sharp Advice, p. 22). Oregon’s manual instead describes diluting bar oil 25% with clean kerosene or diesel and using twice as much (Oregon manual, p. 10). Follow your saw’s manual on which approach it allows.

7. If oil still doesn’t flow

If the tank is full, the vent, bar hole, groove and outlet are clear and the adjuster is open, the fault is inside the saw — usually the oil pump, its drive, or the oil line or pickup in the tank. That is a repair for a servicing dealer or the saw’s service manual. Don’t keep cutting with a dry chain in the meantime.

After running dry

Check the bar for blue spots on the rails, which Oregon says mean the rails have overheated and softened — replace both bar and chain if you find them (Oregon manual, p. 95). A chain run dry can also reach its wear limits early. See when to replace a guide bar and when to replace a chain.

Sources

• STIHL USA — Sharp Advice for chain saw owners (PDF): quick summary (pp. 2–3), lubrication (p. 10), special cold weather care (p. 22)
• Oregon — Safety & Maintenance Manual (PDF): oil in cold weather (p. 10), saw chain maintenance rules (p. 16), how to lubricate your saw chain (p. 21), guide bar maintenance (p. 88), guide bar troubleshooting (p. 95)

Checked against these sources on October 1, 2026.