Checking Oil - Hot vs. Cold Engine

Nightlock24 · Oct 25, 2022

So I know the owner’s manual says to wait approximately 3 minutes after turning off the engine before checking the oil level.

What I’m trying to figure out is, does that mean wait no longer than 3 minutes before checking… or does it mean wait at least 3 minutes before checking? In other words, if I wait much longer than 3 minutes, will the reading be inaccurate?

I’m mainly asking because I find this dipstick very hard to read when the engine is still warm (even if I wait 3 min), but if I let the car sit overnight and check the oil first thing in the morning when the engine is cold, I find it very easy to read the oil level. Anyone know if it’s okay to wait this long? I noticed the manual doesn’t specifically say you have to get up to operating temp before checking, so I’m hoping my method of just checking in the morning is okay.

harr2969 · Oct 25, 2022

Longer is more accurate.

Most oil will flow and settle to the bottom very quickly after shutting off the motor, but the longer you wait, more will settle.

It's diminishing returns though.
Maybe 1 min is 95%
Maybe 2 mins us 99%
Maybe 3 mins is 99.5%

Im just throwing out numbers, but the last little bit doesn't make much difference. It makes more difference if you're parked on a slope.

Zeroptzero · Oct 26, 2022

If you check it cold in the morning pull out the dipstick and wipe it off and reinsert it, then take the proper reading. If you try to read the dipstick upon first removal the level could be artificially high, so remove , wipe, reinsert, remove and read.

iLLuSiVe · Oct 27, 2022

Zeroptzero said:
If you check it cold in the morning pull out the dipstick and wipe it off and reinsert it, then take the proper reading. If you try to read the dipstick upon first removal the level could be artificially high, so remove , wipe, reinsert, remove and read.

This^

But also waiting more than 3 minutes won't make your reading inaccurate, just means everything has cooled off and settled more

SoonerCivic · Oct 28, 2022

Check it in the morning. Don't over think it.

PNWFE1 · Oct 30, 2022

Oil expands and become more viscous under high temperature, checking your oil before your commute on a level surface is ideal.

Cold weather will affect the reading but much less than checking it after continuous use.

Zeroptzero · Oct 30, 2022

be consistent in your oil level reading technique. You can be down a quart of oil without entering the engine damaging zone, so small differences in how you read oil won't make a difference, just be consistent. I have yet to add a drop of oil to my Si in 11 months of ownership and a lot of miles on her. I bought a spare quart of oil when I got the car to use for topping up purposes but it just never needs it. It may take a few years to go through that quart if things stay the same.

Checking Oil - Hot vs. Cold Engine

Nightlock24

harr2969

Zeroptzero

iLLuSiVe

SoonerCivic

PNWFE1

Zeroptzero

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