Checking the level and consistency of engine oil is an essential step in keeping your car up and running. Yet, if you are new to this whole checking and changing oil thing, you may not know how to do it properly or when to change the oil on your new car. One of the questions that often comes up is: Do you check the oil with the car running? There are a couple of reasons why checking or changing the oil when the car is running is a bad idea, but the main reason is that you are not going to get an accurate reading.

Here is the explanation.

**Note** – A quick hello to anyone reading this, I’m Alastair and this is my site Synthetic I started this site to help people with their oil questions, and hopefully what you’re about to read will help answer your questions. This page may include affiliate links to the likes of Amazon, which if you make a purchase I qualify to earn a (typically small) commission. Don’t worry as this won’t cost you anything, the likes of Amazon pay any commissions. Thank you in advance for your support as this helps bring you more (hopefully) helpful content.

Do You Check The Oil While The Engine is On?

No, you do not check the oil when the car is running and hot. As mentioned above, there are a few reasons why this is a poor choice. Firstly, when you remove the dipstick, the oil levels are not going to be correct. When the car is running, the engine oil is moving through it, lubricating the parts. Thus, if you attempt to see how much oil is in the engine while it is on, you are going to get lower reading than the actual oil level.

In reality, your car may have enough (or even too much). If you accidentally pour in engine oil after the reading, you could end up overflowing the reservoir. Too much oil is not a good thing, either. The crankshaft will come into contact with the engine oil, aerating it. Frothy oil cannot do its job, which could lead to premature engine wear and tear.

Is It Safe to Check the Oil While The Car is Running?

No, it is unsafe to check the oil when the car is running. Here’s why: a general car engine gets to be around 195-220 degrees F (90-104 degrees C). The oil alone can reach 250 degrees (120 degrees C). Now, for those who are unaware, an adult will receive third-degree burns when exposed to water that is 150 degrees F (65.5 degrees C) for more than 2 seconds. Imagine what could happen if you accidentally touch the engine when trying to remove the dipstick. Worse, how badly could you get burned if you drip some oil onto your exposed hand?

Secondly, there are moving parts in the engine bay when the car is running. Even though the dipstick is located out of the way, those pistons, belts, and fans are dangerous. People end up with clothing yanked, hair pulled, and even cuts, scrapes, and much worse from dealing with moving machinery all the time.

Final Thoughts on When to Check Your Oil

In short, you do not want to check the motor oil when your car is turned on. Not only is the reading going to be low, but you are also risking your health and safety in the process. Instead, shut your engine off and wait 2-15 minutes before proceeding with a reading. This is the same for changing the oil. Now that you know, be sure to read up on the differences between clean and dirty engine oil.


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