In a word YES!
What happens if I put too much oil in my engine?
Before we get to the scary bit let's look at the reasons for adding oil to your engine between getting your vehicle serviced. The most common one is the oil warning light on the dashboard coming on to alert you of a problem with your engine oil level or engine oil pressure.
What should I do if the engine oil warning light comes on?
STOP THE ENGINE! It's important to remember that the engine and parts around it will be very hot.
As soon as it's safe to do so find a place to stop, such as a car park, layby or filling station. A filling station is ideal as they're generally flat, you can usually find rags or tissue, which will come in useful at the next stage, as well as being able to purchase engine oil should your engine require a top up.
First of all open the bonnet of your car, the bonnet release lever is generally in one the footwells of your car. Pull it until the bonnet of your car pops up a little, then move around to the front of the car. If the bonnet opens from the front, which they do on most modern cars, then there will be a secondary safety catch somewhere under the front centre of the bonnet which you push with your fingers to release the bonnet completely and lift to gain access to the engine bay.
How do I check the oil level in my engine
Look for the dipstick, it will usually have a plastic coloured pull ring on top, used to pull it out of the engine. The dipstick reaches into the bottom of the engine so will be covered in the oil that splashes around in the engine whilst it's running, so grab a rag or cloth and pull it out of the engine, taking note of where to put it back later, and wipe it clean of excess oil.
If you look at the end you'll see 2 marks and these are there to give you the correct oil level, sometimes marked as Min and Max.
Push the clean dipstick all the way back in, remember to give it a firm push to make sure it's all the way in, and then pull it out again, if the oil now covering the tip is between the Min and Max marks on the dipstick then you have the correct amount of oil in the engine.
If there's no oil on the dipstick or the level is below the Min mark then you should add oil a 250ml (approx 1/2 pint) at a time and recheck the level as described above to ensure you don't overfill it. Once the level reaches above the min mark then that is enough as some expansion with heat does occur.
So can you overfill your engine with oil?
Believe it or not too much oil in and engine is as dangerous to the engine as too little.
What can happen if there's too much oil in my engine?
If the oil level is high enough then the cranshaft webs will dip into the oil as it turns which will whip up the oil introducing air and turning it into froth. This restricts the pressure produced in the oil pump stopping it from being able to push the oil around the engine effectively as well as aerating the oil into a mousse like substance and drastically reducing it's ability to lubricate.
Higher pressure in the crankcase can also force oil passed the piston rings where it enters the combustion chamber and burns with the fuel. In a petrol engine this will foul up the spark plugs as well as create a large amount of blue smoke from the exhaust. In a diesel engine where the combustion is cause by compression the added oil acts like fuel and can push the engine to high revs even when you take your foot off the accelerator pedal.
What are other symptoms of your engine being overfilled with oil?
- Engine Oil Pressure Light illuminated on the dashboard
- Oil leaking from the engine bay area under the vehicle
- Smoke and/or a burning smell from the engine bay
- Signs of oil splattered up the rear of the car especially around the exhaust pipe area
- Engine making unusual tapping and knocking noises (this can also happen when the oil level is dangerously low)
If you need any further help with an oil, engine or service light being illuminated on the dashboard of your vehicle please get in touch with your local service centre and if you're local to Bournemouth, Christchurch and Poole then we are ready to help you.
Call 01202 528 667