Insights

Doing your first service and are unsure how much oil is too much oil? It is important to recognise the signs of having filled your engine with too much oil as there can be major consequences for the integrity and safety of your vehicle.

Filling your engine with too much oil shifts the levels in the oil pan resulting in the pressure becoming too high and quite volatile. Excess oil is pushed into the crankshaft and aerates it as it operates causing the oil to become a foamy, frothy substance that cannot offer proper lubrication to the engine.

Becoming familiar with the signs and symptoms of an overfilled engine is important in ensuring that you notice any problems in your car's performance. You should consider the car's oil dipstick indication level, blue exhaust smoke, engine misfires, oil leakage, engine running issues and spark plug fouling when thinking about signs of oil overfilling.

To quickly check if you are over or under-filling your engine oil, check your car's dipstick and ensure that the engine oil level is measured anywhere in between 'FULL' and 'ADD'.

What Is Considered Overfilling Your Engine Oil?

Filling your engine with oil that goes over the FULL mark on your dipstick is considered overfilling it. Although this is unideal, filling your engine oil a little over the maximum is unlikely to cause any major problems towards your vehicle. However, it can have an effect on your driving performance and lead to some serious engine issues if filled in a larger quantity of excess.

How Do I Fill My Engine Without Overfilling?

The best way to fill your engine when doing your own service or top up is to know how much oil your vehicle takes and to check your dipstick for the current levels of oil.

Using your dipstick, you can assess how much oil your car will need for a top up. Usually, a full litre of oil equates to 4 centimetres on your dipstick so you can accurately fill your engine rather than playing a guessing game.

If you are undertaking a full service rather than a top up, you will need to know your vehicle's engine oil capacity. Every car has a different capacity for engine oil that can vary greatly between vehicles, manufacturers and engine sizes.

The quickest way to find out how much engine oil your vehicle can take is to check your owner's manual or the manufacturers website. Generally, smaller engines require less motor oil than larger ones and a regular passenger vehicle will need no more than 5 litres for a full service.

When filling your engine with a top up of engine oil or when undertaking a full DIY service oil change, ensure you are equipped with an oil drain pan, funnel and correct amount of engine oil. These tools will assist in dealing with the messiness of engine oil and ensure that you don't overfill your engine.

What Happens If I Drive With Too Much Engine Oil?

A vehicle has many moving parts and ensuring that all components are running smoothly and effectively is very important. Having your oil levels in check before driving is of the utmost importance when regarding vehicle safety, health and integrity.

If you decide to drive while having too much oil in your engine, it can have a serious effect on your vehicle.

Frothy Oil

When oil is added to a vehicle, it travels into a reservoir called the oil pan which reaches all moving components of the engine. When this is filled too much, it can overflow and reach parts of the engine that it is not meant to contact.

In these cases, an oil leak can be pumped through the engine, and contact components like the crankshaft, which will churn the oil creating an aerated, frothy substance. This results in the oil pump tube and oil filter having a difficult time drawing in oil, essentially having the opposite effect of lubricating the engine and hindering vehicle effectiveness.

Catalytic Converter Burn Outs

A vehicle's catalytic converter filters out contaminants from the exhaust that are dispelled from the engine into the atmosphere. It is common for a catalytic converter to become clogged over time but an oily exhaust can accelerate the process.

While being designed to deal with harmful substances, the catalytic converter is not equipped to superheat oil and can become contaminated, clogged or even melt causing the check engine light to come on and cause problems in the car's exhaust system.

Spark Plugs Fouling

Excess engine oil or fuel that is not burned by the combustion of the engine creates a dirty or fouled spark plug that ends up corroded and faulty

Prolonged leaking oil exposure on a spark plug without cleaning or rectifying the excess oil over a long period of time can become an even more serious issue. Fouled spark plugs, due to oil leakage, can additionally lead to a reduction in fuel mileage, increase engine misfires and can even cause an engine to stop while driving.

Engine Damage

Extra oil in the system causes excess lubrication and can result in excessive pressure on the crankshaft. When oil enters the crankshaft exhaust pipe and runs into the combustion chamber, it can block the suction hose with oil soot and potentially lead to engine overload.

How Do You Know if You've Put Too Much Oil in Your Car?

There are a variety of signs, symptoms and other indicators that you may have noticed when you have filled your engine beyond its oil capacity. Luckily, most of these signs are obvious and can be avoided before causing serious damage.

Engine Oil Leaks

While topping up your oil is not a difficult task it can result in splashes and leaks if you aren't careful and think about putting your oil cap back on correctly.

Beyond that, if you fill your engine with too much oil, it can result in excessive oil pressure and be the catalyst for blown gaskets or seals in the crankshaft, the engine head or valve cover.

Blue Exhaust Smoke

Blue smoke from a vehicle's exhaust is a sign that oil is being burned along with fuel in the vehicle's combustion chamber. When the crankshaft is lathered with oil, it splashes it up into the cylinders of a car more than normal. This causes the oil to eventually make its way into the combustion chamber, burn and go out the exhaust.

Normally, exhaust fumes should be clear and blue exhaust smoke is often a relatively early sign that something is wrong.

Burning Smells

Coloured smoke and a pungent burning smell go hand in hand when you think you've overfilled your engine. If the oil leak is severe enough, the smell and smoke will become more than obvious to you.

A burning smell occurs when a car's engine oil leaks or drips onto hot surfaces within the engine or vehicle, this causes the oil to condensate and create a smell of burning. Although a burning smell could mean a myriad of things are wrong with your vehicle it should not be ignored and addressed immediately.

Engine Starting and Running Issues

A tandem effect of oil leaking and fouling spark plugs is ignition and running issues.

If you are having trouble starting your vehicle or it becomes sluggish and less effective when running it may be due to difficulty properly igniting the air and fuel mixture. This mixture moves the pistons that turn the engine over.

This issue can also cause a vehicle to stall while driving so ensuring your spark plugs are not faulty and that your engine oil is at an appropriate level is top priority. Replacing spark plugs or getting your oil changed by a local mechanic are quite low on the list of costly repairs so ensuring that these services are done on your car correctly is of the utmost importance.

How Do You Fix An Overfilled Engine With Excess Oil?

You can fix an overfilling issue quite easily if you catch it early or you prepare beforehand. To remove excess oil you will need to release it by finding the drain plug and having a plastic oil pan beneath to catch the excess. You will not need to completely drain it but removing some of the old engine oil should bring you back to a level amount of engine oil.

Depending on the other signs and symptoms of the issues, the fix could become more complicated. If this is the case or you have any questions about your vehicle, you can get a quote from one of your local mechanics with Enji to find out what needs to be done before more damage occurs.