If you have a lawn, you probably have a lawn mower. Proper maintenance of your lawn mower is important to keep it running as long as possible. All engines need oil to lubricate the engine. However, different engines need different kinds of oil. Can you use car oil in a lawn mower? Read on to find out what you need to know.
Can You Use Car Oil in a Lawn Mower?
“It depends” is the short answer. If you have an older mower that has a two-stroke engine, you have to use special oil for it. If you have one of the newer four-stroke engines, you can use some of the better types of car oil in your mower. Generally, SAE-30 or 10W-30 oil can be used in a four-stroke mower engine. It is important to consult your owner’s manual to verify the type of oil the engine needs.
What Is In Car Oil?
Originally, car oil was just oil and a few additives. It was intended to lubricate the engine and not much else. Today’s oil is much more sophisticated. Oil still makes up 70-90% of car oil. The other 10-30% of the car oil is additives intended to act as detergents, friction modifiers, antioxidants, corrosion inhibitors and viscosity index improvers, and more. How much and which additives are put in car oil is usually proprietary, so you have to depend on the words used to describe the oil to determine what type of oil fits your four-stroke mower. The right additives make the oil work better and extend the life of the engine. For example, oil for a new car has different additives in it than oil for a high mileage car.
How Does Car Oil Work?
Car oil is used to lubricate, clean, cool, reduce friction, and protect the engine. The oil runs through an oil filter that removes the dirt, combustion residues, and other gunk from the oil. All oil breaks down over time and must be changed. Synthetic oil, born in a laboratory, generally lasts longer than regular oil so doesn’t have to be changed as often. However, it is usually more expensive than regular oil.
What Is In Four-Stroke Small Engine Oil?
Whether it is synthetic or mineral oil, four-stroke small engine oil has a lot of zinc to protect against wear and tear in the engine. These oils also have detergent additives to clean the deposits from combustion. The oil has the correct viscosity to start well in cold weather but run well even in hot weather.
How Does Four-Stroke Small Engine Oil Work?
Four-stroke small engine oil lubricates, cools, carries away the ash and carbon of combustion, and extends the life of your engine.
What Is In Two-Stroke Small Engine Oil?
The base oil for a two-stroke engine can be actual oil, castor oil, a mix of synthetic oil and oil, or synthetic oil. It also includes additives, but they are different than the additives in car oil. This oil is mixed with gasoline and put in the gas tank. There is no separate reservoir for oil on two-stroke engines. I got my first mower a long time ago. It came with a small bottle of small engine oil. I was totally baffled when I went to put the oil in the mower because there was no oil reservoir. I had to call my Dad and ask him what to do with the oil. Good times!
How Does Two-Stroke Small Engine Oil Work?
Two-stroke engines are air-cooled. They need a way to remove heat in addition to the air cooling. Air-cooled engines run about 100F hotter than most cars. Small engine oil lubricates, reduces friction, removes additional heat from the engine, and cleans the engine of dirt, combustion by-products, and gunk. The oil also acts to seal the engine gases into the combustion chamber by not letting those gases leak into the pistons and valves.
Two-Stroke and Four-Stroke Small Engine Oil Versus Car Oil
It can be helpful to see the differences between 2 stroke and 4 stroke lawn mower oils, and car oil.
| Two-Stroke Oil | Four-Stroke Oil | Car Oil | |
|---|---|---|---|
| Temperature | Designed to run at 280-300F | Designed to run at higher temperatures than automobiles but lower than two-stroke engines | Designed to run at 180-200F |
| Zinc Content | Higher levels of Zinc, an antioxidant and anti-wear additive | Higher levels of zinc for anti-wear and antioxidant properties | Lower levels of zinc |
| Motor | Motor can operate on its side or upside down, oil still works | Can't run on side or upside down, oil will not work | Cannot operate on its side or upside down, oil does not work |
| Where? | Oil is mixed with fuel | Has oil reservoir and the oil goes in it, not the fuel | Has oil reservoir and the oil is added to it, not the fuel |
| Additives | Is missing many additives that are in car oil | Has more additives than two-stroke oil but they are different from many car oils | Has multiple additives |
Can you use car oil in a mower with a two-stroke engine? No, you cannot. If you do, ash builds up on the spark plug. Residue builds up in the combustion chamber. Many of the car oil additives interfere with proper lubrication of a two-stroke motor. Using car oil in a two-stroke engine will ruin it.
Is it ok to use car oil in a lawn mower with a four-stroke engine? Some car oils, yes. A premium car oil (SAE 30 or 10W-30 oil) will work in your motor. New mowers are now pretty much always four-stroke mowers. If you have an older mower, you will know it is a four-stroke engine if there is an oil reservoir.
A Few Final Words
In summary, the answer to the question, “Can you use car oil in a lawn mower?” depends on the engine of your lawn mower. Car oil ruins two-stroke engines but lubricates four-stroke engines just fine. If it is a premium oil such as SAE 30 or 10W-30 oil you can use car oil in your four-stroke mower.
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