Draining oil hot or cold questions?
- Thread starter ZZman
- Start date
- Status
gathermewool
Site Donor 2023
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
Please don't take this the wrong way, but please Google. I find it very odd that you've been a member since '08 and have almost 5k posts, but don't know the basics of oil viscosity. Kind of makes it seem as if you're pulling our leg, man.
But I thought the point of the "w" meant better flow in cold environments?
Please don't take this the wrong way, but please Google. I find it very odd that you've been a member since '08 and have almost 5k posts, but don't know the basics of oil viscosity. Kind of makes it seem as if you're pulling our leg, man.
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
That is true, but it is all relative. As I understand it, a 10W-30 has the viscosity that a 30-grade oil has at 100°C. However, at temperatures below-zero, it changes to have the viscosity that a 10-grade would have at those temperatures. Does that make sense? I could be wrong.
But I thought the point of the "w" meant better flow in cold environments?
That is true, but it is all relative. As I understand it, a 10W-30 has the viscosity that a 30-grade oil has at 100°C. However, at temperatures below-zero, it changes to have the viscosity that a 10-grade would have at those temperatures. Does that make sense? I could be wrong.
Nick1994
$100 site donor 2024
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
The first number and the second number in oil viscosity have absolutely no correlation to each other. They could have even used letters in it, so a 5w30 they could call a Bw30 or something.
Here, read this.
https://bobistheoilguy.com/motor-oil-101/
But I thought the point of the "w" meant better flow in cold environments?
The first number and the second number in oil viscosity have absolutely no correlation to each other. They could have even used letters in it, so a 5w30 they could call a Bw30 or something.
Here, read this.
https://bobistheoilguy.com/motor-oil-101/
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
Yes, but that does not mean that oil is thinner when cold and thicker when hot.
But I thought the point of the "w" meant better flow in cold environments?
Yes, but that does not mean that oil is thinner when cold and thicker when hot.
It means better flow than a non multi weight oil at low temperatures.
It DOESN'T mean better flow than when hot.
Since you are doing your own OC, did it ever appear hot oil was thicker than cold?
The empirical evidence should have indicated you weren't understanding the W rating correctly.
It DOESN'T mean better flow than when hot.
Since you are doing your own OC, did it ever appear hot oil was thicker than cold?
The empirical evidence should have indicated you weren't understanding the W rating correctly.
Last edited:
Warm is hot enough to drain the contaminants with the oil. Hot is fine but no need to get it so hot it will burn you.
- Joined
- Jul 2, 2007
- Messages
- 5,294
I drain hot after about 20 minutes of engine operation, driving not idling. I let it drain at least ten minutes.
Originally Posted By: Quattro Pete
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
Yes, but that does not mean that oil is thinner when cold and thicker when hot.
Interesting. So a 5 w is not thinner when cold and a 50 weight not thicker when hot? I thought the higher the the number the thicker it is and says when hot? Maybe the w really only pertains to very cold Temps and not really normal oil change Temps.
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
Yes, but that does not mean that oil is thinner when cold and thicker when hot.
Interesting. So a 5 w is not thinner when cold and a 50 weight not thicker when hot? I thought the higher the the number the thicker it is and says when hot? Maybe the w really only pertains to very cold Temps and not really normal oil change Temps.
Last edited:
I always do an oil change after coming back from somewhere so the oil has reached operating temperature along with the engine. I open the hood and put it up on the jack, get the safety stands in place, the catch pan in place, new oil etc. ready, rags, gloves on etc. This all takes about 20 minutes or so, so by then the engine & oil has cooled a bit and I find while the oil and filter is still very warm it's not burning/scalding hot and it seems to drain out the exact fill capacity in the manual.
Last edited:
Originally Posted By: eyeofthetiger
I drain my oil cold.
It has nothing to do with suspending contaminants or reducing startup wear. I just prefer working on cold engines.
I've found the oil filter spills a lot less when removing when cold.
I drain my oil cold.
It has nothing to do with suspending contaminants or reducing startup wear. I just prefer working on cold engines.
I've found the oil filter spills a lot less when removing when cold.
Warm sometimes hot
Originally Posted By: SHOZ
Originally Posted By: eyeofthetiger
I drain my oil cold.
It has nothing to do with suspending contaminants or reducing startup wear. I just prefer working on cold engines.
I've found the oil filter spills a lot less when removing when cold.
I find though that the oil draining takes forever. Although I guess it depends on your definition of cold. Canada Cold / Illinois Winter Cold?
Originally Posted By: eyeofthetiger
I drain my oil cold.
It has nothing to do with suspending contaminants or reducing startup wear. I just prefer working on cold engines.
I've found the oil filter spills a lot less when removing when cold.
I find though that the oil draining takes forever. Although I guess it depends on your definition of cold. Canada Cold / Illinois Winter Cold?
Last edited:
Originally Posted By: ZZman
Originally Posted By: Quattro Pete
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
Yes, but that does not mean that oil is thinner when cold and thicker when hot.
Interesting. So a 5 w is not thinner when cold and a 50 weight not thicker when hot? I thought the higher the the number the thicker it is and says when hot? Maybe the w really only pertains to very cold Temps and not really normal oil change Temps.
It seems odd to have to explain this to someone who's been a member here for 9 years and has 4K+ posts, but anyway...
Take two oils for example: 5w-50 and straight SAE50. They will both thicken as the temperature drops - these are the laws of physics. The difference is that the the 5w-50 will not thicken AS MUCH as SAE50, but they will both still thicken.
Originally Posted By: Quattro Pete
Originally Posted By: ZZman
But I thought the point of the "w" meant better flow in cold environments?
Yes, but that does not mean that oil is thinner when cold and thicker when hot.
Interesting. So a 5 w is not thinner when cold and a 50 weight not thicker when hot? I thought the higher the the number the thicker it is and says when hot? Maybe the w really only pertains to very cold Temps and not really normal oil change Temps.
It seems odd to have to explain this to someone who's been a member here for 9 years and has 4K+ posts, but anyway...
Take two oils for example: 5w-50 and straight SAE50. They will both thicken as the temperature drops - these are the laws of physics. The difference is that the the 5w-50 will not thicken AS MUCH as SAE50, but they will both still thicken.
AZjeff
$50 Site Donor 2023
Drained the oil hot last time in the truck because I wanted to do a UOA and pull a sample mid-drain. Pulled the plug, hot oil on the gloved hand, oil everywhere when I jerked my hand back,dropped the plug in the pan. Also had to watch out for hot engine parts. Never again hot. Another obsessive BITOG thing.
I’ve always drained cold. I don’t care to handle hot oil...
Haven’t lost an engine yet.
Haven’t lost an engine yet.
I drain hot and use a Kevlar knit glove to grab the oil filter.
- Status
