What does engine oil do?
It seems obvious but understanding what engine oil does helps us understand why it is so important to make sure good oil is going into your car and it is changed regularly.
Engine oil’s main job is to lubricate key components, protecting them from corrosion and keeping them cool when the vehicle is being driven.
Oils are made up of base stock and additive and are developed by oil brands and engine designers and builders, which is why you will see car maker specific oils.
The base stock is the part responsible for the lubrication and the additives control the consistency of the oil and protect against wear.
- Lubrication: Engine oil forms a thin film between moving parts within the engine, such as pistons, bearings, and camshafts. This reduces friction and wear, preventing metal-to-metal contact that could lead to damage and premature failure.
- Cooling: Oil helps to dissipate heat generated by friction within the engine. It carries heat away from critical components, such as the pistons and cylinder walls, helping to maintain optimal operating temperatures.
- Cleaning: Engine oil picks up dirt, debris, and combustion byproducts as it circulates through the engine. It suspends these contaminants in the oil, preventing them from settling on engine surfaces and forming deposits that can impede performance and efficiency.
- Sealing: Oil seals small gaps between piston rings and cylinder walls, helping to maintain compression and prevent leakage of combustion gases. It also helps to seal other mating surfaces, such as gaskets and seals, preventing oil leaks.
- Corrosion protection: Engine oil contains additives that help protect metal surfaces from corrosion and rust, particularly during periods of engine inactivity or exposure to moisture.
- Viscosity: Engine oil viscosity refers to its resistance to flow. It’s crucial for maintaining proper lubrication across a range of operating temperatures. Oil that is too thin may not provide adequate protection at high temperatures, while oil that is too thick may impede engine startup and circulation at low temperatures.
- Grades of Oil: Engine oils are graded based on viscosity and performance standards set by automobile engineering societies and trade bodies. Common grades include 5W-30, 10W-40, and 0W-20, where the numbers before the “W” indicate the oil’s viscosity at low temperatures, and the numbers after the “W” indicate viscosity at high temperatures.
What happens when oil gets old?
As engine oil cleans as well as lubricates, it picks up dirt, debris and other contaminants. Over time this causes the oil to degrade, become thick and eventually, provide no lubrication for the engine components. If the oil gets to this tar like state the engine could sieve and become redundant requiring a new engine or car.
A new engine will cost upwards of £5000, and it given how busy garages are it could take months to get your car back on the road.
This happens more than you may think given that 8 out of 10 drivers don’t know how often the oil in their car should be changed and a third of drivers delay or skip services to save money!
