Since the 1800’s oil has been used to power cars in the UK. From the earliest cars like the Benz Motor Car to the modern ICE cars we see on our roads, they all rely on oil. But the use of oil hasn’t come without a cost: the severe environmental issues that its use has caused.
EVs have emerged as a cleaner more sustainable alternative to the petrol engine, but do electric cars use oil? Or has the EV age completely severed ties with oil?
This article explores the mechanics of EVs and how they function, we review the oil EVs need and and the other fluids that keep an electric car going.
Do Electric Cars use oil?
Electric cars don’t use engine oil as traditional petrol or diesel cars do because they don’t have internal combustion engines. Instead, electric cars use electric motors powered by batteries. However, some EVs may use lubricants for other parts, but this is not the same as the regular engine oil used in ICE cars.
Why do traditional petrol or diesel cars need oil?
Internal Combustion Engine (ICE) cars need oil for several crucial functions:
- Lubrication
Oil reduces friction between moving parts, preventing wear and damage. - Cooling
While the car’s cooling system primarily uses coolant, oil also helps dissipate heat from the engine’s internal components. - Cleaning
Oil carries away dirt that might otherwise cause engine damage. - Sealing
Oil helps seal the gap between piston rings and cylinder walls, ensuring efficient combustion. - Protection against corrosion
Oil has additives that prevent rust and corrosion inside the engine.
Without oil, a traditional petrol car would quickly overheat, wear out, or get damaged.
Why don’t EV Electric Motors need oil?
Electric motors in electric cars don’t need oil like internal combustion engines do because they are designed to operate completely differently:
- Simpler Design
Electric motors don’t have as many moving elements as petrol motor does. Without things like valves, camshafts, and pistons, there’s less friction which means less need for lubrication. - No Combustion
Electric motors operate without combustion. Since there’s no burning of fuel, there’s no risk of overheating that requires oil for cooling. - No Exhaust Emissions
Electric motors produce no exhaust emissions, so there is no need for oil to trap and carry away contaminants. - Consistent Operation
Electric motors can keep going without the extreme temperatures and pressures seen in ICEs, reducing the wear and tear that means you need oil. Where ICE cars overheat and break down, EVs tend to keep going. The majority of roadside EV breakdown recovery is down to EV batteries running out of charge, rather than the engine failure that is common in ICE cars. - Direct Drive
Many EVs use a direct drive mechanism, so it doesn’t need a proper gearbox (gearboxes need to be lubricated with oil!).
What fluids and lubricants do EVs use?
For most EV owners, the regular maintenance and refilling of fluids are limited compared to traditional what they are used to with their old petrol vehicle. This is one of the factors that makes EVs much cheaper to run than petrol cars.
Generally, the fluids that an EV owner might need to occasionally check or refill themselves include:
Windshield Washer Fluid
Used to clean the windshield. This is always the most commonly refilled fluid by car owners, electric or otherwise. Usually, this runs out just as you set off on a long journey and you find yourself behind a truck firing mud off the road at you!
Brake Fluid
Over time, brake fluid can degrade or become contaminated, so you need to replace it. However, checking and refilling brake fluid is generally done during service checks and EV MOTs, most owners don’t do this themselves unless they’re comfortable with electric vehicle maintenance.
Coolant
Batteries and power electronics can generate heat during operation. A coolant fluid is typically used to maintain the correct temperature.
Although this doesn’t need looking at often, the coolant levels for the battery and power electronics cooling systems need to be at the right level. This should be handled by professionals, especially given the importance of the battery’s thermal management.
Transmission lubricant
EVs have single-speed gearboxes or reducers that require lubrication. Specialised fluids or lubricants are used to reduce friction.
Power Steering Fluid
Vehicles with hydraulic power steering systems, whether ICE or EV, require power steering fluid to assist in turning the wheels.
Air Conditioning Refrigerant
This is used in the air conditioning system to cool the vehicle’s interior. Many new EVs use a refrigerant that can also be employed to cool the battery in extreme conditions.
Thermal Management Fluids
Apart from the primary coolant for batteries, some EVs use separate fluids for heating and cooling other components or the cabin, especially in cold climates.
While these fluids and lubricants are needed, most have long lifespans and will not need attention from the vehicle owner. And when they do, it’s usually best handled by professionals during scheduled maintenance.
EVs generally require a lot less attention than the oil changes and fluid replacements typical of ICE vehicles. As technology gets better the designs of EVs will evolve and we will likely need even less fluids in future.
How much oil do electric cars use?
How much oil electric cars use is virtually nothing compared to their traditional petrol counterparts. Electric cars, as discussed, do not consume engine oil as traditional internal combustion engine cars do.
This is due to the fundamental distinction that EVs rely on electric motors, which don’t need the oil-based lubrication essential for combustion engines. However, some electric vehicles will use oil in the other components mentioned above.
While the exact volume can vary based on the EV model and its design, the amount is significantly less than traditional cars and they don’t need to be changed anywhere near as often as petrol motors.
Do hybrid cars use oil?
Hybrid cars, just like petrol cars, have an internal combustion engine with an electric motor.
The ‘engine’ component of a hybrid car operates similarly to that of a conventional petrol or diesel car which means that it absolutely needs to use engine oil to work properly.
The oil plays a pivotal role in ensuring smooth engine operation. It lubricates moving parts within the engine, reducing friction that can cause undue wear and potential damage.
This is vital as engines have loads of fast moving components that are in close contact, and without oil, the engine would quickly deteriorate.
Engine oil in hybrid vehicles has a few other uses. It helps in cooling the engine, complementing the primary cooling system which uses coolant. By circulating through the engine, oil carries away heat from internal components, thereby helping in temperature regulation.
Oil acts as a cleaning agent, picking up contaminants and ensuring they don’t settle and cause harm inside the engine. It’s also instrumental in sealing minute gaps, especially between piston rings and cylinder walls, ensuring the combustion process remains efficient.
Lastly, modern engine oils contain additives specifically designed to prevent the internal engine components of a Hybrid car from rusting or corroding.
The final word on electric cars and oil
It feels like with more and more EVs hitting the streets in the UK, the relationship between cars and oil is going through a big transformation.
Electric vehicles challenge our views on how we should be maintaining our vehicles – long gone are the days of putting on overalls and spending the afternoon tinkering with an oil change in the garage.
For centuries, the roar of engines and the associated smell of oil at petrol stations have gone hand in hand. Now, with silent EVs and the ability to install an EV charging station at home – things are changing.
Yet, it’s essential to recognise that while electric vehicles mean that we don’t need as much oil, they haven’t eradicated it entirely. Some parts of EVs, like cooling systems or brake fluid, still require lubricants or fluids (even with regenerative braking systems). These uses are minimal though, especially when compared to petrol cars.
Even though electric cars do need oil, the very fact that the primary function of EVs, i.e. to drive us places, can happen without a drop of oil is pretty amazing and shows just how far this technology has come.
John is the Editor and Spokesperson for Electric Car Guide.
With over 20 years of writing experience, he has written for titles such as City AM, FE News and NerdWallet.com, covering various automotive and personal finance topics.
John’s market commentary has been covered by the likes of The Express, The Independent, Yahoo Finance and The Evening Standard.
