You already know that engine oil levels should be monitored regularly. You also understand that engine oil must be replenished as soon as the level goes below the threshold and the warning light flashes. But should you pour the oil while the engine is still hot?
Confusing Advice From People in the Know
Some advise that the oil should be poured in immediately and that it is not necessary to wait for the engine to cool down and it will not damage the car.
Others say that it makes sense to wait and open the oil reservoir with the cold engine, as there may be a risk of burns or fire.
So what should you do and are there other factors you should pay attention to before pouring oil into the reservoir?
Will Cool Oil Damage A Hot Engine?
The first question is the most critical one- will pouring oil into hot engines damage any parts of the car? So, there may not be any potential damage if oil is poured into the tank when you just stopped the car, and the engine may still be warm.
This can occur when you are in a hurry and notice that the engine oil level is below and you can’t wait for the engine to cool down to get on the road.
Remember the science lesson we learned in school that most things change their viscosity with heat as does oil. The motor oil you pour in is at room temperature, and the engine is hot due to recent usage.
The temperature difference may confuse the oil level reading in the tank, the existing oil will be less viscous, and the new oil will be thicker. You may end up filling less or more oil in the tank. The new motor oil will also heat up soon and expand soon as you restart the car and drive.
The Oil Level May Not Be Accurate
The problem with a hot engine and cool oil is more about the accuracy of oil levels. If you pour very little oil or more than the needed amount, it may cause some problems.
The amount of oil can also be affected by the temperature and inclination of the car, etc. once the car is turned off and the oil levels are checked, the engine temperature plays an important role.
How Can You Ensure An Accurate Reading?
This is when you must allow some time for the engine and inside fluids to settle down. Apart from the temperature, the fluids in the engine constantly move and work while the car is in motion.
The liquid must be allowed to settle down at the bottom, and in the process, its viscosity also reaches some normalcy. Experts usually advise a few minutes- 10 to 15 minutes to allow the oil to settle at the bottom before checking the level with a dipstick.
Wrong readings and you may add more or less than the required amount of oil, and that is an avoidable aspect.
The Question Remains- Can You Put Oil In A Hot Engine?
You know that when you take the car to an expert, they pour oil into the engine even if it is hot. It seems like a no-brainer that it is common to add oil with a warm engine since it has been used recently, and they have many customers to serve and can’t wait for the engine to cool down.
However, it does make sense to wait for a few minutes if the engine is too hot due to a long drive and weather. In fact, residual oil must be drained out, and it is easy when it is still warm and less viscous.
The oil flows out easily when it is less viscous, and that can happen when the engine is still warm. One option is to allow the engine to cool down and drain the oil when it is still not completely cool and becomes too thick.
Safety May Be Compromised If You Add Oil To A Hot Engine
There are some risks associated with any maintenance when the engine is still hot. These are the precautions that one must take while handling a hot engine. Touching any hot components may lead to burns.
Burns may also happen if you try to check the oil level when the engine is still very hot to touch, and it is not advisable to use the dipstick when the engine is still too hot to handle.
If the temperature difference between the oil and engine is too much, it may also lead to smoke, and you may not even be able to see where you are pouring the oil. Oil spills on any other hot component may lead to dense smoke and damage other parts.
In some extreme cases, this may also give rise to a fire. This is likely if the oil enters other parts of the engine if your hand moves or shakes due to the hot parts, or you cannot see clearly due to the smoke.
This is not a frequent accident, but it may happen and must be avoided. Use a funnel to pour the oil, and that, too, after waiting for a few moments, allows the engine to cool down a bit.
Before filling the oil tank, the two most important things to do are to let the engine cool down for a few moments and check the oil level. But if you took the car to a service center, they understand the mechanism and know what they are doing.
How Long To Let Engine Cool Before Adding Oil?
To prevent burning yourself on the hot oil already in the vehicle or on and around the dipstick, wait at least 10 to 20 minutes after the engine has cooled down before adding oil.
You can pour oil when the car engine needs it, and it may happen so that you do not have time to allow the engine to cool down. It is not completely safe but is not completely prohibited either.
Ideally, it would be best if you allowed the engine to cool down to handle the parts easily and accurately measure the oil level. This will help you execute the steps of oil change safely and properly.
If you cannot wait for the engine to cool down, it is best to take the car to a service center.