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Can I use 10W30 In My Mower? Mechanic says yes!

Can I use 10w30 in my mower? You can use 10w30 in a lawnmower engine, however, oil type recommendations will vary between makes and you should, of course, use the oil type specified in your users manual.

Mower oil type, quantity, and the oil filling procedure are covered here in this post but if you need video help check out “Check mower engine oil level”.

How Much Oil?

The amount of oil depends on the engine type and size. Most Briggs & Stratton single cylinder riding mowers and walk-behind mowers like 5W30 or 10W30 oil and will take from empty approximately 1.5 quarts (1.42 lt.), more if they’re fitted with an oil filter 1.62 quarts (1.54 lt.). Twin-cylinder B&S takes 2 quarts (1.9 lt.).
 
Modern walk behind mowers like 5W30 or 10W30, older engines like SAE30, and the average walk-behind mower take about .65 of a quart (.6 lt.) of oil from empty.

Honda, Kohler, and Kawasaki prefer 10W30 oil but using 5W30 won’t hurt them any.

Tractor mower oil chart
Lawn mower oil chart

For the exact spec, check out:

Briggs and Stratton push mower engines

Briggs and Stratton tractor mower engines

Honda specification

Kohler specification

Kawasaki specification

Check out the Amazon link below, mower oil delivered to your door.

Amazon Lawnmower Oil

What Oil Type?

Mostly oil type is dependent upon outside temperatures as this changes the viscosity (resistance to flow) of oil. Modern engines will use a multi-grade such as 10W30 and older engines SAE30.

Single Weight Oil

Single weight oils such as SAE30 have a good working range (40 to 100 deg F), fine for older engines. I prefer to use multi-grade oils, they offer greater protection from temperature swings, and modern mowers were designed to use them. If you’re using any 4 stroke engine in colder temperatures, you’ll need a multi-grade oil.

Multi Grade Oil

Multi-grade oil was developed to help better protect engines within a larger temperature swing range. Oil has a harder time flowing in colder temperatures. Before the development of multi-grade oil engines owners would change their oil to a lighter grade in preparation for winter use. 

Multigrade, so called as they are blended oils. Take for example the grade 10w30. The 10W part relates to the grade of winter oil in the blend and the 30 part relates to the protection offered at hotter temperatures. The resistance to flow rate is tested and graded at 0 degrees F and at 212 degrees F.

Synthetic Oil

Synthetic oil is basically a man-made oil, manufactured in a lab like a chemical. Part synthetic is obviously man-made synthetic oil, blended with oil made by nature. Part synthetic and full synthetic oils will offer the very best protection, however, they’re expensive. 

Detergent

Another great advantage to modern blended oils is the detergent component which actually cleans and beaks down combustion-related contaminates, (Black sludge aka Black death) which would eat away at the metal and clog up vital oil passageways.
 
Use only quality oils, otherwise, you may void your warranty. Look for the seal of ​API (American Petroleum Institute) and ACEA (Association des Constructeurs Europeens d’Automobiles). I tell my customers that an oil change is a must-do maintenance that should be performed at least once per season. Oil is cheap relative to a new engine.

How to Check Oil

The oil level is best checked cold and on level ground. If your engines have been running, just allow the oil to settle for a few minutes before checking.

Ride-on mower

Level – The mower should be cold and parked on level ground. If your mower has already been running, allow the oil to settle for few minutes before checking.

Dipstick

Locate – Locate the dipstick. Usually, they are positioned on the side of the engine. The dipstick itself will be marked with an oil symbol or can be brightly colored.

Dipsticks

Dipstick – The style of dipsticks varies, however they all operate on the same idea.

Dipsticks come in different styles but all do the same job. A lower mark (L) and a full mark (F). When the oil level is in the hatched area, it’s OK, but aim to have it at the F mark.

Low oil

Low – This oil level is way too low. It’s below the low oil level mark indicated here by the hole.

adding oil

Adding Oil – If you need to add oil, add in small amounts and allow it to settle before rechecking.

Oil level good

Correct – This is the correct level for oil. Check the oil with every refueling.

Dipstick too full

Too Full – Too much oil here, it’s way above the full mark. This can damage the engine, cause oil leaks and excessive white smoke. If the oil level is very full, it will stall the engine.

We’ll need to remove the excess oil.

Check out my mower repair video library, it covers checking oil levels along with a ton of other common mower repairs that any homeowner can do.

If your oil level is high and your engine is smoky, you may have a carburetor fault, don’t run the engine as you will damage it. I wrote this guide to help you check and repair/replace your carburetor – “Carburetor troubleshooting”.

Removing Oil

If you have overfilled the oil, removing some is easy. I wrote this simple guide including pictures, on how to service your tractor –  “Tractor mower tune-up” or check out the video here. To remove excess oil we have two choices, drain it out or siphon it out.

Draining is messy, hit and miss as to how much to drain off. I use a siphon in the workshop, it’s clean and easy to control. You can check out the siphon I use here on the “Small engine repair tools” page, they aren’t expensive and you’ll find other uses for it, drains gas, coolant, brake fluid, and water too.

Oil drain

Draining – Gets the job done but messy and hit & miss.

Syphon

Siphon – Clean and controllable.

Why Check Engine Oil

The correct quantity and quality of the oil are critically important to the life of the engine. Some mowers are fitted with a safety switch which won’t allow the mower to start if the oil level is low. Not all mowers have this feature so it’s important to check your oil regularly.
 
An incorrect oil level can damage your engine beyond economic repair. An oil level that’s too low causes excessive heat, friction, and premature wear or complete seizure of the engine. An oil level that’s too high can cause aeration of the oil, reducing its ability to cool and lubricate. Too much oil can also cause your engine to leak oil, smoke, or just not start.
 
Lawnmower engines that don’t have an oil filter generally don’t have an oil pump. This means they employ the splash method of lubrication, an overfull oil level on these types of engines can be especially harmful.

When to Change Engine Oil

It is advisable to check your oil regularly, an easy way to remember is to check it every time you fill the fuel tank. Change your oil once per season or every 50 hours of operation. The oil needs to be changed as it gets contaminated and diluted by fuel and other deposits associated with combustion and metal friction. 

If neglected this oil turns into a diluted sludge which offers little protection to the engine. Changing your oil is a simple job that you can do yourself, usually, only basic tools are required. Follow this simple guide and you’ll be tuned up in no time at all, check out “Lawn mower oil change”.

Related Questions

Is there a difference between 4 cycle oil and regular oil? There is no difference between 4 cycle oil and regular engine oil, they are the same. Common engine oils used in lawnmowers are SAE30, 5W30, and 10W30.

Does a lawnmower need oil to start? A lawnmower engine will start without oil, but you must never do so, even running it for a short time will cause serious engine damage. Some models are fitted with a fail-safe switch that prevents low oil engine starting.