When are you supposed to check your oil, when the engine is warm or when it's cold?

[lenFeb]

I checked oil level in my GT350 according to our car manual after driving for a while(when oil is expended(warm). And turn the engine off and wait 15 minutes for the oil to drain into the oil pan. The oil level was at the upper hole of the dipstick.
But, I checked the oil when the engine was cold, it was at the lower hole of the dipstick.
I found this article regarding this topic: https://www.cartalk.com/content/when-are-you-supposed-check-your-oil-when
Interested, what peoples comments would be. And should I add oil when the engine cold and reading low oil level or should I just trust oil level when the engine is warm?

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[key01]

I would stick with warm 15 minutes after shut down. Regardless, tho keep it consistent.

 

[Big Ernie McCracken]

Yeah the manual really doesn’t say other than turn engine off and wait 15 minutes. I have always checked after engine has run for a bit and then shut off, for an accurate reading. Sometimes I will check before I even start just to see where it is at.

 

[Hack]

I always checked it cold, because I assumed it would be more consistent. When the engine is running there's a lot of oil up in the valvetrain. When you shut the engine down the oil starts draining to the pan. Depending on how hot the oil was, it might take less or more time for the oil to drain down. Plus it's easier to check oil when the engine isn't hot.

But just checking it somewhat regularly is probably good enough. Once I knew how my car behaved I didn't check the oil very often. It just didn't use oil.

 

[lenFeb]

I always checked it cold, because I assumed it would be more consistent. When the engine is running there's a lot of oil up in the valvetrain. When you shut the engine down the oil starts draining to the pan. Depending on how hot the oil was, it might take less or more time for the oil to drain down. Plus it's easier to check oil when the engine isn't hot.

But just checking it somewhat regularly is probably good enough. Once I knew how my car behaved I didn't check the oil very often. It just didn't use oil.

GT350 owners manual said to check oil in 15 min after engine turned off, that gives enough time for oil to drain down into oil pan. The oil lever reading is different by one quarts when I check it in completely cold vs. worm after say 15-20 min.

 

[Hack]

GT350 owners manual said to check oil in 15 min after engine turned off, that gives enough time for oil to drain down into oil pan. The oil lever reading is different by one quarts when I check it in completely cold vs. worm after say 15-20 min.

A lot of people on here have said they had varying and inconsistent readings of the oil level. I didn't really have that problem checking it cold all the time. I think it's more difficult to get a consistent reading when you try to check it hot.

Maybe I'm wrong about this, but I interpreted the 15 minutes in the manual to be a minimum. Meaning if you don't wait at least 15 minutes the reading will show low because all the oil hasn't drained down yet. So obviously you can do whatever you want, but I think it's better to check it cold unless for some reason you absolutely can't wait for the engine to cool off (track side between sessions or something).

The goal is to make sure the engine has enough oil - isn't over filled or under filled. It's not rocket science and IMO there's no need for the engine to be a certain temperature and a certain % of the oil to still be up in the valve train in order to get a good reading.

 

[NoXiDe]

Engine oil gets pumped into the galleries through the help of the oil fuel pump. If you're asking this question, it's safe for us to assume that you're asking because your concern about oil consumption. If you drop your car off at Ford, they'll check it after it sits for 15 minutes. Some Engineer came up with that time based on gravity and etc. It's basically the minimum amount of time that is considered fair to calculate oil consumption. However, I suggest waiting a full day to let it completely drip. I also suggest checking every 500 miles unless you think you're engine is guzzling oil.

 

[proeagles]

I usually try to check mine first thing in the morning while its cold. I believe the whole 15 min thing is designed to allow all the oil to drain back into the engine. Bonus, the engine is not hot and you can't get burned fiddling with the dipstick.

 

[CANTWN4LSN]

Curious if you have repeated this check. Seems excessive to be a whole quart different between 15 minutes and over night. Mine shows minimal change between 20-30 minutes and over night.

 

[lenFeb]

I usually try to check mine first thing in the morning while its cold. I believe the whole 15 min thing is designed to allow all the oil to drain back into the engine. Bonus, the engine is not hot and you can't get burned fiddling with the dipstick.

Thanks. What is your oil level when you check it cold vs. warm(after 15-30 min)? I live in central NJ and it's cold in my garage, around 40-45F.

 

[Tomster]

I check mine cold, in the same spot where I park it in the garage every time. I thought the manual said 20 mins after engine shutdown...…. but Im not going to look it up.

 

[lenFeb]

Curious if you have repeated this check. Seems excessive to be a whole quart different between 15 minutes and over night. Mine shows minimal change between 20-30 minutes and over night.

Yes. That's my point of this thread. I'll be checking regularly and will post the results.

 

[proeagles]

Curious if you have repeated this check. Seems excessive to be a whole quart different between 15 minutes and over night. Mine shows minimal change between 20-30 minutes and over night.

Pretty much the same.

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