Signs Your Small Engine Needs an Oil Change
How to tell when a mower, snowblower, or generator engine is due for an oil change, and why the right interval depends on your engine’s manual.
Small four-stroke engines on mowers, snowblowers, and generators work hard. They run hot, often in dust or cold, and usually without an oil filter. Clean oil at the right level is one of the cheapest ways to help one last.
There isn’t one interval that fits every engine. Manufacturers set their own schedules, often by hours of use and with a separate interval for a brand-new engine’s first change. Check the owner’s manual for your machine. Beyond the schedule, these are the signs it’s due.
You can’t remember the last time
This is the most common one. If an engine has gone a full season or more and nobody remembers changing the oil, it’s almost certainly due.
The oil is dark, gritty, or thick
Check on level ground with the engine off and cool. Wipe the dipstick, reinsert it as the manual describes, and pull it again. Fresh oil is amber and translucent. Oil that’s black, sludgy, or feels gritty between your fingers has done its job and needs replacing.
The level is low
Small engines can burn or leak a little oil, and an engine run low can be seriously damaged. Some engines have a low-oil shutdown that stops them from starting or running. If the level is consistently dropping between checks, have the engine looked at, since that can point to a larger problem.
The oil looks milky
Milky or foamy oil can mean water or fuel has gotten into the crankcase. Don’t just top it off. Have it checked.
The oil smells like gasoline
Gas in the oil can happen when fuel leaks past a worn or stuck part. It thins the oil and reduces protection. This is worth a professional look rather than just a change.
It’s the end of the season
Changing the oil before storing equipment means the engine sits for months with clean oil instead of used oil. See how to store outdoor power equipment for the rest of the storage checklist.
A note on two-stroke engines
Two-stroke engines, common on string trimmers, many chainsaws, and some blowers, don’t have a separate crankcase oil to change. They’re lubricated by oil mixed into the fuel at the ratio the manufacturer specifies. Using the wrong mix or straight gas can ruin the engine.
Getting it done
Oil changes are a service Westland Small Engine Repair wants to do more of. If you’d rather not deal with draining and disposing of used oil, call or text (734) 400-0790, or see the oil change service page.
This article is general guidance. Always follow the owner’s manual for your specific machine.