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How to fill chainsaw bar oil

Updated: 22 October 2026

The chain is sharp, the tank you topped up was the wrong one, and the bar pays for that. This page is how to fill chainsaw bar oil on a petrol or electric saw, then how to see that oil is reaching the rail before you commit to a log. Know which cap is which, keep waste engine oil out of the bar system, and confirm the oiler works before and during the job. The handbook still owns the pump screw and the cap symbols. The bottles are on the [chainsaw oil comparison](/hub/forestry-tools/chainsaw-oil). Peter F. used HSE guidance and those listings, and did not lab-test oils. A qualifying purchase can earn a commission at no extra cost to you.

The chain is sharp, the tank you topped up was the wrong one, and the bar pays for that.

Our top picks

Oregon Oregon Biodegradable Chainsaw Chain Oil, 1 litre

Best overall

Oregon Oregon Biodegradable Chainsaw Chain Oil, 1 litre
9.7/10about £11.13
View offer
Rotatech Rotatech Universal Chainsaw Chain and Bar Oil, 5 litres

Rank 2

Rotatech Rotatech Universal Chainsaw Chain and Bar Oil, 5 litres
9.7/10about £21.99
View offer
Carlube Carlube XPM011 Anti-Fling Chainsaw Oil

Best value

Carlube Carlube XPM011 Anti-Fling Chainsaw Oil
8.7/10about £3.69
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On this page
  1. 1.Bar oil versus fuel
  2. 2.Filling safely
  3. 3.Checking oil flow
  4. 4.When consumption spikes

Bar oil versus fuel

A petrol saw usually has two tanks. One takes fuel. One takes bar and chain oil. Guessing from cap colour is how two-stroke mix ends up on the chain. Mix is petrol for the engine. Bar oil is the thick lubricant. HSE INDG317 says keep lubrication working and warns against discarded engine oil, which performs poorly and is a skin-contact concern. AFAG308 expects the oiler to work in the pre-use checks. An electric saw often has only an oil filler. If the handbook says there is no oiler, this fill does not apply. If you have poured mix into the oil cap, empty it into a sealed container, wipe the body, refill with bar oil, and run the flow check before any cutting. What to buy is on the chainsaw oil buying guide.

Filling safely

Stop the chain and switch the saw off. Wipe grit off the cap and identify it from the handbook symbol, then pour until the tank is usefully full and the cap can seal. There is no universal fill mark. Use a level line or sight if you have one. Otherwise leave a little room so heat does not push oil out. Wipe spills before you start. HSE fuel guidance is to move away from the cans before a petrol saw fires. About 4 metres is commonly cited as that gap, unless the handbook sets another distance. Gloves keep oil off your skin, eye protection goes on before the flow check, and the rest of the kit goes on before you cut.
Oregon Oregon Biodegradable Chainsaw Chain Oil, 1 litre

Testsieger

Oregon Oregon Biodegradable Chainsaw Chain Oil, 1 litre
9.7/10about £11.13
View offer

Checking oil flow

A full tank only helps if the pump puts oil on the bar. With the brake set as the handbook requires, and nobody in line with the bar, hold the nose a few centimetres above light card and blip the throttle. You want a fine oil line, or a wet film on the rail. Dusty chips and a dry rail mean stop. A dry chain can blue the bar in one session. Check again when you refuel, change a battery, or take a break. There is no one consumption figure. A line in the morning and nothing after lunch means an empty tank, a blocked port, a stuck pump, or oil too thick for the temperature. Card, short run, visible oil, or stop. Small tanks are on electric chainsaw oil.

When consumption spikes

A longer bar or a warm day can empty a tank sooner. A dry bar with oil still visible is a different fault. With the saw stopped and the plug lead or battery off, look for a cap that never sealed, debris in the outlet, an oil hole that misses, or a chain on the wrong way. Reseat the bar as the handbook shows and test on card again. We will not give a number of turns on the pump screw. The handbook states more oil and less oil. If the card stays dry after that, stop cutting. A brake that will not reset, or kickback you do not understand, is a reason to hand the saw to someone competent, and tree work beyond your training is a reason to hire an arborist. Drained oil goes to a recycling centre or a licensed collector, not back into the next saw.

Common questions

Which tank is bar oil on my saw?
Use the handbook symbol, not the looser cap. On a petrol saw the fuel tank takes petrol or two-stroke mix, and the oil tank takes bar and chain oil. Many electric saws have only an oil cap. If you cannot tell, stop and read the manual. A wrong fill means empty the tank, wipe up, and refill with bar oil before any cut.
How do I know the chain is getting oil?
Hold the nose a few centimetres above card and blip the throttle as the handbook allows. A fine oil line, or a new film on the rail, means oil is arriving. Dry dust, a bright rail, or a blue bar means it is not. Stop. If the card stays dry after you reseat the bar, the next step is the handbook’s pump check or a repair.
Do electric saws use less oil?
Shorter sessions often mean fewer refills. That is time on the cut, not a different oil. We have no millilitres-per-hour figure, so this page will not invent one. A dry bar still damages the rail. Use the same card check. The oil is still bar and chain oil unless the handbook names a grade.
What if oil leaks from the cap?
Stop and wipe the saw and the ground. Crossed threads, a torn seal, and grit are the causes you can see with the saw off. Clean the threads, fit the seal, and seat the cap. If it still weeps onto the rear handle, replace the cap or the seal, or have the saw repaired.
Can I mix brands in the tank?
Nothing on these listings describes a reaction between two bar oils, so topping up with another bar oil is ordinary. Keep two-stroke mix and used engine oil out. If a site rule needs bio, empty the old oil first rather than a capful of bio on a mineral tank. Take the waste to a recycling centre. Council rules differ.

Related pages

Best chainsaw oil UK

Biodegradable vs mineral chainsaw oil

Chainsaw oil

Chainsaw oil buying guide: viscosity, tack and can size

Electric chainsaw oil for cordless saws and mini tanks

Sources

Sources from the research digest, last checked on 22 October 2026.

  1. HSE — Chainsaws at work (INDG317) (retrieved 22 October 2026)
  2. HSE — Top-handled chainsaws (AFAG308) (retrieved 22 October 2026)
  3. HSE — Working with chainsaws (retrieved 22 October 2026)
  4. STIHL UK — BioPlus chain oil (retrieved 22 October 2026)
  5. Oregon biodegradable chainsaw chain oil, amazon.co.uk listing B002X3IDBK (retrieved 22 October 2026)
  6. Pennine Lubricants — biodegradable chainsaw oil (retrieved 22 October 2026)
  7. Rock Oil — Groundsman Biochain (retrieved 22 October 2026)