Is overfilling an engine with oil bad?

Can you really have too much of a good thing? Yes, of course you can. Your car likes oil, in fact, it needs it to operate. But the amount of oil that is required to lubricate your engine’s moving parts is a set quantity.

Why is overfilling the engine oil bad? Well, that’s for a variety of reasons which we’ll tell you about.

But before we start, check the oil level, this tells you the level of oil in your car. It should be around or just below the full mark. Then read your owner’s manual and find out the amount that needs to be topped off if required.

If your car takes 5L of oil and the dipstick is halfway full DO NOT PUT 2.5L OF OIL IN YOUR CAR.

What happens if I put too much oil in my car?

Your engine has an oil sump. This is where all your oil sits. It is sucked out of the sump (aka ‘oil pan’) by the oil pump and pushed back into the sump via the oil filter when it’s done it’s job.

If you overfill your oil, you can absolutely damage your engine.

The oil pump draws oil out of the sump as we now know. If there is too much oil, it can prevent proper oil pressure and recirculation. This can mean too little or way too much oil goes through the engine.

This can mean you destroy your engine by grinding metal on metal.

Or you can hydraulic your engine and destroy it in that way.

Either way, not ideal.

What are signs that there’s too much oil in my car?

There are some clear indicators.

Dipstick level too high. Check the dipstick, is it too high? If it’s well above the full level then you’ve overfilled your oil, or, parked on a really steep gradient before checking.
There’s signs of oil on the spark plugs. This usually means that oil is getting into the combustion chamber. If it’s wet then it means it’s seeping in. If it’s caked on and black, it’s burning while the motor is running.
It is literally coming out of your exhaust. That is a terrible sign anyway. It can be from overfilled oil but it can also be from worse causes.