Due to car oil typically being cheaper and more readily available, it can be a tempting alternative when it’s time to change the oil in your ATV. After all, oil is oil, right? As it turns out, that may not be the best idea, at least not in the long run.
As we’ll cover in this post, there are differences between the two oil types that can significantly impact your vehicle’s performance and longevity.
The crucial difference between ATV and Car oil is how they are designed to perform under diverse operating conditions. ATV engines run hotter, under more stress, at higher RPMs, have a smaller oil volume, and don’t have as complex emission equipment as cars. ATVs with a common sump require wet clutch-safe oil.
So how do oil manufacturers design ATV oil and car oil differently? And how do different operating conditions affect what properties are required by the oil?
Additives Are Used to Tailor the Oil to Vehicle Specific Needs
Engine oil protects the engine against wear from friction, deposit formation, oxidation, and deposit formation and helps prevent overheating.
Cars and ATVs operate under very different conditions, presenting a unique set of challenges for the motor oil. Sadly, there exists no universal oil formula that will provide adequate performance under all conditions.
The engine oil in an ATV is exposed to a far more severe environment and needs to withstand a broader range of stressors than any automotive oil.
So how do the oil manufacturers overcome this challenge? They use oil additives such as friction modifiers, viscosity modifiers, and others to tailor customized blends for each application.
A typical bottle of engine oil consists of about three-quarters of base stock and one-quarter worth of various additives.
The amount and composition of additives determine how well an oil performs under various operating conditions.
Motor oil blends optimized for cars will not do as good of a job when used in an ATV. Some additives used in car oil are redundant and may even cause harm if used in ATVs. The same applies if ATV oil is used in cars.
So what unique challenges and conditions are we discussing, and why can’t one oil formula meet them all?
ATVs With a Common Sump Need Wet-Clutch Compatible Oil
A common sump is where the engine, clutch, and transmission all use the same body of oil contained in one shared oil sump.
Cars, as well as most modern ATVs, do not use this design but rather separate motor oil and transmission oil.
However, ATVs with manual transmission and wet clutches usually have a common sump system. In this case, the oil you use must be compatible with all components it touches. More specifically, the motor oil needs to be wet-clutch compatible.
The problem with using automotive oil in common sump ATVs is that it contains friction modifiers that can cause significant problems when used with wet clutches. The same applies to additives in automotive oils designed to improve fuel economy.
The additives and modifiers can cause clutch slippage, creating a glazed surface on the clutch plates. This leads to additional clutch slippage issues and premature clutch wear.
This is why you should never use automotive oil in stand-alone ATV transmissions.
Wet-clutch compatible oil contains no friction modifiers that could cause clutch slipping and is labeled “Jaso MA.”
Note that oil for automatic transmissions does contain friction modifiers and is labeled “Jaso MB”
ATVs Require a different Viscosity Range than Motor Oils Provide
Viscosity is a measure of a fluid’s resistance to flow. Fluids with lower viscosity flow faster, while fluids with greater viscosity flow slower. For example, water has a viscosity of 1.0, while raw honey has 12.200.
In oils, the viscosity is displayed in a format like this: 5W-30.
- The first number indicates the viscosity when the oil is cold.
- The latter number suggests the viscosity when the engine reaches operating temperature.
Conventional automotive motor oils are usually 10W-30 or 5W-20 or similar viscosity ranges.
ATV engines and transmissions, on the other hand, require oils with a broader viscosity range to work correctly and to provide proper protection and lubrication in extreme cold or heat.
As an example, my Polaris Sportsman uses 5W-50 viscosity. Other ATV brands typically require oils in ranges from 0W-40 to 10W-40. Please refer to the user manual to discover what viscosity the manufacturer engineers have determined is the ideal viscosity for your particular bike.
Oil manufacturers use viscosity modifiers to create oils with viscosity numbers optimized for ATV use. These numbers are typically not found in automotive engine oils.
Using oil with the wrong viscosity can lead to oil consumption and gear pitting, leading to gear failure.
Another issue with using automotive motor oil in an ATV is how well it maintains a stable viscosity over time. Cars typically change the oil in shorter intervals, reducing the need for viscosity stability.
On the other hand, ATVs are often left not in use over extended periods; this puts more pressure on the ATV oil, which needs to work just as well months down the road as when it was poured in.
ATVs Run at a Higher Engine Temperature
ATVs regularly run hotter than most cars, with cylinder temperatures ranging from 90 to 200°C (194 to 392°F). When oil temperature increases, it loses viscosity and becomes thinner. Thinner oil does not lube and protects the engine as efficiently against wear.
Another issue with overheating oil is accelerated chemical decomposition, also known as oil oxidation.
For every 18°F (10ºC) increase in oil temperature, the decomposition rate doubles, it is effectively reducing oil life expectancy by half.
Motor oil used in ATVs must be formulated to withstand such intense temperatures.
An ATV Has a Much Smaller Engine and Oil Sump
The oil sump in ATVs is significantly smaller; the amount of engine oil in circulation is only about 1/5th to 1/10th that of a car. This further adds to how effective oil needs to be in keeping the ATV cool.
The smaller ATV engine requires oil formulated for smooth flow through the narrow pathways inside the engine.
ATVs Engines Run at Higher Speeds – RPM
While a car spends most of the time cruising at engine speeds ranging from 1500 to 2500 RPM, an ATV regularly reaches much higher levels.
The main concern with engine oil at high engine speeds is oil foaming.
As engine speed increases, the mechanical action of the rotating crankshaft causes an increasing amount of tiny air bubbles to begin forming in the oil.
ATV engine oil and other high-speed engines are explicitly formulated to release this air from the oil as fast as possible, as this helps prevent foam buildup.
When using the wrong oil, causing foam to build up, the oil lubricating properties are reduced drastically, increasing wear in gears and bearings or possibly causing engine failure.
Oil foaming can also cause the oil to deteriorate faster.
ATV Oils Require Greater Shear Stability
An oil’s shear stability is a measurement of its resistance against change in viscosity caused by mechanical stress or shear.
When oil with poor shear stability gets exposed to excessive mechanical stress, it gets thinner.
ATVs are regularly used to perform heavy work at low speeds. This creates high tension on the gears and increases the load on the engine bearings.
The oil film must be strong enough to withstand this tension without collapsing, also known as shearing.
Automotive engine oil is not designed to withstand high-load, high-pressure operation, at least not to the same degree.
ATV Oil Contains More Corrosion Inhibitors
Most ATV oils contain additives to prevent internal engine corrosion or rust. Corrosion typically happens due to internal condensation if an engine sits for extended periods without being used.
Most cars are used regularly, if not daily, and thus oil manufacturers do not emphasize corrosion prevention as much.
Long-term storage corrosion protection is just one of the properties you might miss out on when opting to use car oil in your ATV.
Different Emission Requirements Apply to ATVs Than Cars
Cars use various high-tech emission-reducing components to comply with today’s emissions requirements.
In most places, these requirements do not apply to ATVs. This means that cars have many complex components you won’t find in an ATV.
The lack of emissions equipment in ATVs allows oil manufacturers to include higher levels of beneficial additives in their ATV-oil formulas that are not compatible with components used in cars. Examples of such additives are zinc and phosphorus.
Is Car Oil and ATV Oil the Same
Car oil and ATV oil is not the same as they contain different additives and modifiers to give the oils unique properties customized to fit the specific needs and requirement of the two vehicle types.
Is ATV Oil the Same as Motorcycle Oil?
ATV oil and Motorcycle oil share many of the same properties, but there might be differences to consider. Motorcycle oil matching the proper JASO specification as directed by the ATV manufacturer will probably work just fine. But to be on the safe side, it’s best always to use the oil specified by the manufacturer.
Can I Use Car Oil/Motor Oil in ATV
Using automotive motor oil in an ATV can cause immediate or gradual damage over time. The most common issue is caused by using non-wet-clutch compatible automotive oil in a wet-clutch ATV. This can cause clutch slippage and, eventually, clutch damage.