Rick's Free Auto Repair Advice

How to check oil level in your engine

DIY steps to check the oil level in your engine

What you need to check your oil level

1) A clean rag
2) A bottle of the recommended oil

Steps to check your oil level

1) Locate the handle for the dipstick and pull it all the way out of the dipstick tube, using your rag to wipe off all the oil.
2) Reinsert the dipstick all the way into the dipstick tube making sure it’s fully seated.
3) Remove and read the oil level

steps to check oil
How to read an oil dipstick

Carmakers use several variations of oil dipsticks. Some contain letters to indicate FULL and LOW, while others simply include holes or notches and expect you to know what they mean. So it’s important for you to know how to read an oil dipstick.

Here’s a rundown of the most common types of dipsticks.

how to read oil dipstick
Plastic and crosshatch motor oil dipsticks-1
When to add more oil?

You can add oil any time the oil level is below the full mark. But most carmakers recommend adding oil when the dipstick shows you’re a half quart low, or midway between the FULL and LOW marks.

How to add more oil to your engine

The recommended oil is listed in your owner’s manual and on oil fill cap on enginethe oil fill cap on your engine. NEVER use a different oil. Why? Because the oil life monitoring system is calculated to work properly only if you use the recommended oil.

Next, pay attention to the bottle. Notice how the spout is off center and the top of the bottle is angled?

The bottle is designed that way to help you pour a smooth flow without a funnel and without “glugging.”

Most people think you should start the pout with the spout closest to the oil fill hole on the engine. WRONG!

Holding the bottle in that position will cause it to burp and glug as you pour and that will cause the oil to shoot out between burps.

Instead, start your pour slowly with the angled spout up. It’s a bit  harder to aim that way, but it makes for a

pour motor oil

Pour motor oil the right way, with the angled spout up. That allows air into the bottle so it self burbs and eliminates glugging and oil spills.

much smoother pour.


When to check your oil level — hot or cold?

In the past, all carmakers recommended checking your oil level when the engine was cold. That way, all the oil from the top of the engine had drained down to the oil pan, so you’d get an accurate reading.

However, several years ago Ford Motor Company began recommending checking your oil level when the engine is hot. Why? Because they knew that very few people checked their oil first thing in the morning when the engine was cold. Quite the contrary, most people check their oil level when they’re at the gas station and the engine is still hot. So Ford recalibrated their oil dipsticks to reflect proper oil level with the engine is hot.

Not all carmakers recommend this, and checking your oil when the engine is hot does mean that some of the oil hasn’t drained down to the pan from the top of the engine. However, tests show that the amount of oil that doesn’t drain down right away amounts to no more than 1/8/quart, which is about 4-ounces. In other words, not enough to make much difference when reading your dipstick.

Does oil expand when hot?

Yes. The amount motor oil expands depends on the type of oil being used; conventional or full synthetic. But here’s a general rule of thumb; when the engine is at full operating temperature, oil expands about 6%.  If your engine hold 4.5-qts (4.5-qts x 32-oz/quart = 144-oz), it will read approximately 8.64-oz. more when the engine is at operating temperature compared to when it is cold (144-oz x 6%= 8.64-oz).

What happens if you overfill your oil?

Carmakers list a specification for the amount of oil to add during and oil change. The amount shown includes an amount needed to fill the oil filter. In fact, some specifications show two numbers; one with a new filter and one without. The problem is that manufacturers of spin-on filters can make their filters any size they want. If they use a more efficient filter media, they can downsize the overall size of the can. Or they can use a less efficient filter media and make a larger size can.

So it’s possible to add the exact amount of oil to your engine but still be slightly overfilled if the filter you chose is smaller than the OE filter.

Or, you can be slightly overfilled if you didn’t let the oil oil drain long enough

engine oil overfilled
Most engines can handle a slight overfill without problems

Overfilling by 1/2-quart is usually not a problem with most engine. However, if you’ve overfilled by more than that amount, that extra oil can cause big problems like:

An overfilled crankcase can splash too much oil onto the oil rings, causing them to drag too much oil into the combustion chamber. That can cause spark plug fouling, carbon buildup, and even catalytic converter damage.

An overfilled crankcase can cause oil foaming (due to the crankshaft whipping air into the oil) which cause overheating and accelerated engine wear.

If the oil dipstick shows more than 1/2-quart overfilled, drain off the excess.

©, 2023 Rick Muscoplat



Posted on by Rick Muscoplat

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