How Long To Let Engine Cool Before Adding Oil?

One of the common maintenance your car needs is an engine oil change. Manufacturers and expert gearheads recommend changing your engine oil every 5,000 to 10,000 miles, depending on whether you use mineral or synthetic oil.

Regardless of the oil change interval and the type of oil, you must take all precautionary measures when changing the engine oil. One of these measures is to let the engine cool before adding the new motor oil. But how long to let engine cool before adding oil?

I’ll answer that and other related questions in this article. Grab a seat and make yourself comfortable while I explain all you need to know.

putting oil in car while engine is hot

How long to Let the Engine cool before adding oil?

Whether you want to change the engine oil completely or top it up, let it cool down.

Gearheads recommend letting your engine sit for minimum 20 minutes to let the motor oil fully settle in the sump. After that, check the oil level with a dipstick to know the exact level before adding oil. Always allow the engine to cool before checking the oil levels or adding or changing it.

But how long does it take for an engine to cool down completely? Let the engine rest for at least 30 minutes if you have driven it for a long time. It is important to note that putting oil in a car while engine is hot will not ruin it. However, you should wait for the engine to cool if you are doing a complete oil change.

Topping up means adding extra oil to the existing engine oil. So if you are wondering, can you top up engine oil without draining it? The answer is yes.

Topping up and changing engine oil requires different procedures. So you should let the engine cool before changing the oil.

Allowing the engine to cool down before draining the oil in the sump will make the work much easier. The oil will be warm. Plus, it’ll reduce the risk of burning off your hand.

Meanwhile, if you haven’t driven your car all day and want to change the engine oil, start the vehicle and let it idle for a while. This will make the oil warm but not extremely hot. By doing so, the motor oil will flow faster when draining it.

how long to wait after adding oil to car

Why should you let Engine cool down before adding oil?

There are two significant reasons to let the engine cool before adding oil. They include;

More accurate reading

The primary reason other expert mechanics and I advise allowing the engine to cool before topping up the oil doesn’t necessarily have anything to do with the car engine. The truth is, adding oil to a hot engine will not ruin the engine.

This, however, doesn’t mean it is no longer advisable to let the engine cool before checking, topping, and changing the engine oil.

The oil will have a volatile reading when the engine is extremely hot. So, allowing the engine to cool down will let the oil settle in the oil sump, giving you an accurate reading.

To avoid accidents

You should let the engine cool before topping up or doing an oil change to avoid burning off your hands. Technically, other components in the engine compartment will be hot since the engine is still hot.

The risk of burning off your hand increases if the oil filter is underneath the exhaust manifold in the engine bay or close to the exhaust pipe under the vehicle. Also, extremely hot oil can burn off your hand when draining the oil. Sometimes, some engine oil will pour on your hand while draining it. Imagine what will happen if the oil is extremely hot.

how often should you top up engine oil

Frequently Asked Questions – FAQs

Q: Does adding oil end overheating?

Keep in mind; motor oil cools and lubricates internal engine reciprocating parts. If the oil level is low, it’ll have several consequences on the engine. One of which, you probably gauzed, is overheating. However, other factors like no/low engine coolant, broken or loose belts, clogged or leaking radiator, engine thermostat malfunctions, etc., can cause overheating engine.

Therefore, adding oil will stop overheating if the low engine oil is the root cause. But if the overheating results from issues in the cooling system, adding engine oil will not stop it.

Q: Does your car have to be cold to put oil in?

As explained earlier, your engine should be cold before adding oil. If you have driven your vehicle, let it cool down before adding engine oil. This will let the motor oil settle down in the oil sump for an accurate reading and to prevent accidents.

Q: Can I drive my car straight after putting oil in?

Driving your car straight up after an oil change will put the reciprocating engine parts at risk of not being properly lubricated, invariably leading to a catastrophe. Therefore, you have to wait a bit after adding oil. But how long to wait after adding oil?

After adding oil, idle the engine for about 30 seconds to 1 minute and turn it off. Wait for a minute or two before checking the engine oil. Once you confirm the oil is gauged, you can hit the road.

Q: Can I add oil while engine is running?

If you’re wondering, should car be running when adding oil? The answer is no. You should always turn off your engine and allow it to cool down before adding engine oil. Adding oil to a running engine will cause oil to spill on the valve cover or hot components in the engine bay.

This is true because once you open the oil filler cap, the engine will be pushing out air through the filler cap due to the pressure inside. The air from the engine will not allow you to pour the oil easily. Plus, you cannot get accurate oil readings while running the engine.

Should I drive the car just after adding oil?

As explained earlier, adding oil and changing oil are two different things. While it is recommended to let the engine cool before adding or changing oil, you can change the motor oil even when the engine is hot.

You can pour oil into an engine when hot, warm, or cold. In any case, it is best to let the engine cool to prevent burning off your hand and to have more accurate readings.

If you have been reading to this point, you’ll no longer ask how long to let engine cool before adding oil. For an accurate reading and to prevent accidents, let the engine cool down for at least 20 minutes before adding oil.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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