There are many reasons why it is better to let your car’s engine cool down beforehand check the oil level with the dipstick or when you drain or change the oil. Hot synthetic oil can reach over 200 F° and burn your hands and skin. Also, allowing a hot engine to cool for 5 to 10 minutes allows the recirculating oil to drain inside the sump, allowing for more accurate readings when checking the oil level.

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But is it safe to add fresh oil to a hot engine? I do it constantly when needed, and the only thing I have to worry about is dealing with the intense heat inside the engine bay. If you want to add oil when the level is low or after doing a few hot laps around the racetrack, it is safe to do so, provided you wear safety equipment (some gloves and goggles) and shut off the engine before proceeding.

Unlike opening a radiator cap, where there is a high risk of scalding or burning if you try to open it when it is hot, there is no such danger in opening the oil cap on a hot engine, provided you shut off the engine first. Doing so while the engine is running can cause hot oil to spray everywhere, causing a huge mess and possible burns.

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The best time to drain the oil is when the engine is warm. The oil becomes thinner or loses viscosity and drains faster when hot, leading to more efficient oil changes. At the same time, the contaminants trapped in oil are more likely to flow out more efficiently at higher temperatures.

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If you are planning one DIY oil change in the morning, start the engine and drive around for 15 to 30 minutes, park the car on level ground, turn off the engine and wait five minutes before draining the oil. The next step is to let it all sit for about 20 to 30 minutes, giving more time for all the oil to drain. The final task is to replace the oil filter, reinstall the oil drain plug and fill the engine with new oil.

See the owner’s manual to know which oil is best for your car and how often it requires oil changes. In the meantime, be careful when adding oil to avoid overfilling. Always check the oil level with the dipstick before adding oil, whether the engine is hot or cold. Remember to check the oil level at least once a week or before going on a long drive to maintain a healthy engine.

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