If you are in a hurry and your engine requires an oil change, you may wonder whether you can add oil to a hot engine. In brief, yes, you can add oil to a hot engine, but it’s not as straightforward as it appears. Some argue that the engine should be allowed to cool before adding oil.
In this article, we will look at some points to help you decide whether or not to add oil to a hot engine.
What happens when you pour oil into a hot car engine?
There are several myths about cold engine oil causing engine harm when supplied to a hot engine. Some claim that it can cause metal parts to crack; however, this is false. Engine parts are not particularly delicate and do not sustain damage readily.
Furthermore, engine oil is designed to absorb heat. Thus, a heated engine does not affect the engine oil. Countless drivers have changed the oil from a hot engine, thus there is no disadvantage.
However, there are a few things to keep in mind when changing the oil in a hot engine:
Incorrect Oil Reading
When you put hot oil in a hot engine, the oil expands. This is because when cold oil comes into touch with a hot engine, it causes thermal expansion due to kinetic energy, which causes oil molecules to expand.
This can result in unstable oil level readings for some time. You may also notice that your oil tank is taking less oil than usual. After some time, the oil will gradually return to its regular level as the oil molecules absorb the heat in the engine.
Risk to Burn Skin
If the engine is overheated while changing the oil, it’s best to proceed cautiously. When hot engine parts come into contact with your skin, they can cause it to burn. Also, when you open your engine hood while it is excessively hot, hot steam may come directly to your face. After a long drive, the engine’s radiator becomes hot, so avoid touching it.
A temperature of more than 130 degrees Fahrenheit can easily burn your skin in less than 30 seconds. If the car has been operating for a long time, changing the oil is risky since the engine temperature will be very high. In that situation, it is recommended that you wait at least 30 minutes before changing the engine oil.
How Long Does it Take For Engine to Cool?
This all depends on how hot your engine is and how quickly you need to get somewhere. If you have the time, you should let the engine cool down for about 30 minutes or about an hour, and this may help you take a proper oil level reading. Otherwise, your engine oil will be hot, and the readings won’t be accurate.
However, if you are in a hurry, allow the engine to cool for at least 15 minutes so that there is no risk of your skin not burning when it comes into touch with the engine.
How Can I Cool Down my Engine Fast?
You can add oil to a hot engine, but some people prefer to add oil to a cold engine to prevent the risk of overheating and getting proper oil level readings.
The engine will take its time to cool down, but if you are in a rush and want your engine to cool down faster before changing the oil, here are some tips:
- Turn off the air conditioner, as this may enhance the cooling speed of your engine.
- Open the automobile’s bonnet to allow more air to travel through and relieve heat from the engine.
How to Change Oil Correctly
So, during an oil change, you don’t want your engine to be too cold or too hot.
If your engine is-
- Too hot – The oil will expand when it comes into contact with the hot engine leading to the wrong oil level.
- Too cold- When oil is heated, it flows smoothly. When the engine is cold, it is difficult to drain the old oil because it sticks to the oil tank walls.
To replace the oil properly, your engine should be roughly 100 degrees Fahrenheit. To achieve the best results, change the oil 15-20 minutes after the drive, or let the engine warm up for a few minutes if it is completely cold.
- Remove the drain plug with a wrench and drain the leftover oil in the tank. After emptying the old oil, reinstall it.
- Using a filter wrench to replace the old oil filter.
- Put in the new fresh oil.
- Wipe down the dipstick with a cloth. Using a dipstick, check the oil level; it should be between the min and max points. Check again after a few minutes, as the oil takes time to settle.
To summarize, pouring oil into a hot engine is not an issue if you are in a hurry. However, you must use extreme caution to avoid skin burns. Also, oil takes time to settle, so if you don’t mind having less oil in the tank, adding oil to a hot engine is completely OK.
You should let the engine cool for a few minutes before changing the oil for the best results. If you suspect your engine is overheating, contact your mechanic immediately.
Marc is a Young mechanic working full-time in a big garage in Texas. He’s graduated and is well educated in the automobile industry and aims to open his own shop someday for his clients.