How to check the engine oil level

[johnsmellsalot]

I've been on BITOG for a while now and I've read several posts in the past about people getting inconsistent readings when checking the oil level. I've also seen plenty of posts asking about what kind of oil to use.

The best kind of oil to use is the kind that meets/exceeds the manufacturer's recommendations. The oil specifications can always be found in the owner's manual. For my Chrysler, I look for these 3 things when choosing oil: API certification, a viscosity of 5W-30, DaimlerChrysler Material Standard MS-6395.

Oil life monitors display oil life, not the quantity of oil. Therefore, it is a good idea to check the oil level once a week, or during each stop for fuel.

Always refer to your owner's manual. These are general instructions for checking engine oil.

1. Get engine up to normal operating temperature. If your vehicle does NOT have a coolant temperature gauge, run the engine until the cooling fan turns on. Make sure the vehicle is level.

2. Turn off the engine and remove the oil dipstick. Wait 5 minutes before reinserting the dipstick to check the oil level.

Checking the oil when the engine is cold can give you an inaccurate reading. Checking the oil within 5 minutes of the engine being shut off can also give you an incorrect reading.

 

[DragRace]

I've ALWAYS checked oil in ALL vehicles cold,never an issue.

 

[dparm]

Originally Posted By: johnsmellsalot

Always refer to your owner's manual.



It all comes down to this. Too many people guess, use a weird rule of thumb, or have some worthless anecdotal evidence on how to read the car's oil level.

 

[Malo83]

Check mine weekly, and first thing in the morning

 

[NHGUY]

I always check it stone cold.

 

[TFB1]

Originally Posted By: Malo83
Check mine weekly, and first thing in the morning

Agreed...

Assuming the vehicle is level, before first start of the day will give the most consistent reading... No wait, no heat, no problem...

A automatic trans should be checked when hot...

 

[Papa Bear]

Originally Posted By: DragRace
I've ALWAYS checked oil in ALL vehicles cold,never an issue.


+1

 

[oldhp]

+1 on checking cold in morning. I even check as truck sits with a nose down stance. Why? Because that is where it sits, change oil, add all but 1qt of oil to show where 1qt low is, check it next morning after being driven. That's 1qt low, add 1qt, that's full.

 

[Falken]

Morning +1

 

[JethroBodine]

Anytime of the day after the engine has been shut off for at least 30 minutes. On trips I wait until I stop for a meal or at a hotel.

 

[Danh]

Cold is good. Plus, there's no need to remove the dipstick and reinsert 5 minutes later - as a matter of fact, this just gives dust and other contaminants an opportunity to get into the engine. When you're ready to check, remove the dipstick, wipe with a paper towel and reinsert and check.

 

[Errtt]

Most times I check cold.
Driveway is slanted.
After an OC, in garage, level, full, I can place the vehicle on the slanted driveway. After the oil settles, I check and its almost 1/4-qt below the full mark. After that, I know its full if its 1/4 below full.

I know auto tranny generally checked hot. So if full hot, let settle to next day, pull tranny stick when cold/off and see where its is cold, meaning if hot should be on full. Can scribe a light line across stick so if it meets that mark when cold, then it should be full when hot. I know... weird.

 

[BISCUT]

Originally Posted By: Malo83
Check mine weekly, and first thing in the morning

Yup...me 2.

 

[KrisZ]

I check mine cold as well and it's always been consistent. When the engine is warm I have to take two-three readings just to get the correct level.



Originally Posted By: dparm
Originally Posted By: johnsmellsalot

Always refer to your owner's manual.



It all comes down to this. Too many people guess, use a weird rule of thumb, or have some worthless anecdotal evidence on how to read the car's oil level.


Then why post here? Lets shut down this great forum with a wealth of information because all is answered in the owner's manual

.

Fact is that owner's manuals are not bibles. Same goes for service manuals. Owner's manuals are a great source for fluid and capacity information, as well as other maintenance items. However when someone wrenches on their own cars, or is a professional mechanic for a while, they will realize that not all things mentioned in the owner's or service manuals are written with the end user in mind.

So people learn workarounds to make their work easier, more efficient or simply because they can do it another way. Checking oil level cold is just one of those workarounds. It's definitely not worthless anecdotal evidence.

 

[Donald]

Originally Posted By: johnsmellsalot
I've been on BITOG for a while now and I've read several posts in the past about people getting inconsistent readings when checking the oil level. I've also seen plenty of posts asking about what kind of oil to use.

The best kind of oil to use is the kind that meets/exceeds the manufacturer's recommendations. The oil specifications can always be found in the owner's manual. For my Chrysler, I look for these 3 things when choosing oil: API certification, a viscosity of 5W-30, DaimlerChrysler Material Standard MS-6395.

Oil life monitors display oil life, not the quantity of oil. Therefore, it is a good idea to check the oil level once a week, or during each stop for fuel.

Always refer to your owner's manual. These are general instructions for checking engine oil.

1. Get engine up to normal operating temperature. If your vehicle does NOT have a coolant temperature gauge, run the engine until the cooling fan turns on. Make sure the vehicle is level.

2. Turn off the engine and remove the oil dipstick. Wait 5 minutes before reinserting the dipstick to check the oil level.

Checking the oil when the engine is cold can give you an inaccurate reading. Checking the oil within 5 minutes of the engine being shut off can also give you an incorrect reading.


On a normal vehicle with 5 QT of oil the amount of expansion of the oil when it gets hot is very minimal. The ATF and coolant are much larger quantities.

Now trucks with several gallons of oil might be different.

Clearly the vehicle needs to be pretty level. Checking it with the engine just shut off should be reasonably accurate, but if I just shut down the engine and it was 1/4 QT low I would leave it. If it was 1 QT low I would add oil.

Remember the oil runs down to the sump at a pretty rapid rate via gravity. If it did not the sump would be empty and all the oil would be elsewhere. Only a portion of the oil goes to the valve train area, the rest goes around the crank and bottom of the cylinders and that oil just drops almost immediately. So after 1 minute maybe 2 all the oil that is going to "drain" into the sump has drained, the rest will "drip" into the sump and is insignificant.

 

[TFB1]

Originally Posted By: Donald

Remember the oil runs down to the sump at a pretty rapid rate via gravity. If it did not the sump would be empty and all the oil would be elsewhere. Only a portion of the oil goes to the valve train area, the rest goes around the crank and bottom of the cylinders and that oil just drops almost immediately. So after 1 minute maybe 2 all the oil that is going to "drain" into the sump has drained, the rest will "drip" into the sump and is insignificant.


Exactly...

Only thing I'll add is, if you're going to check it hot, it must be hot... Starting the engine and not allowing it to warm 15 min in summer and probably at least 20 min in winter before checking is a definite no no...

 

[KitaCam]

The one hint I'd offer is that oil will adhere to the stick better when the stick is cold...

 

[Bamaro]

Originally Posted By: KitaCam
The one hint I'd offer is that oil will adhere to the stick better when the stick is cold...

Yup, it seems easier to actually read the dipstick when cold. Just pull it out and read it, no need to even wipe it off first.

 

[Eddie]

My Mazda manual says check the oil after stopping the engine for 5 minutes or more, which I do. I have checked overnight and after 5 minutes and see little or no difference. Why is this such a problem for some and not others? Read your manual and follow the instructions.