0W20 Cold Start Flow/Circulate Time How Long?

[Srt20]

The turbo is the absolute last thing Id worry about. There no hard psi there. Its a fan, thats it. And its really low rpm at idle also. If she starts it, and the second it fires she goes WOT, well maybe, but everything else will be stress too.

 

[Shannow]

You are talkiing 45F.

The engine is lubricated with a postiive displacement oil pumps, and the 0W oil is over 70F from any issues that it might have from a pumpability aspect.

At 45F, anything from 0W to 5W through 20W will get to where it needs to be in virtually exactly the same time.

The "0W" only "flows" better than a 5W even only in the very minuses of F's

 

[Nederlander75]

0w20's the Devil.

 

[KrisZ]

The number before W is not a grade, it's a rating, winter rating to be specific. In order to meet this rating an oil has to be below the maximum CCV and MRV viscosity and those maximum figures are quite high.
Because of that there is quite a big variation of viscocities at low temperatures. A 0w20 will be much thinner than a 0w40 for example, despite both having the same 0w rating. Whereas the hot viscosity grades are much more tightly controlled.

So if flow speed was so important, there would not have been such a big variation allowed or another spec would have been introduced. Like HTSV was for hot viscosity grades.

 

[KrisZ]

Originally Posted by tig1
Flow is very important to the upper end of an engine. Here is a video in extreme cold.

https://www.youtube.com/watch?v=OWiQyR7PWII


That video confuses people more than helps and it obviously continues to confuse you despite numerous explanations as to what was demonstrated in that video.

But let me explain it again, so at least others can see through this presentation.

They chose to compare a 0w30 to a 10w30 oil at -35C startup. But the 10w is rated at -30C, whereas 0w is rated at -40c. So they clearly took an oil that was outside its rated low temp performance.
Why do you think they didn't choose a 5w oil? Could it be because it's rated at -35C and would not show any difference from 0w in regards to flow? Now, that would not make for a compelling presentation, would it?


That video only demonstrates what happens when you take the oil outside it's cold rating. You cannot assume that it applies to all cold temperatures, because it doesn't.

 

[Shannow]

Originally Posted by KrisZ
That video only demonstrates what happens when you take the oil outside it's cold rating. You cannot assume that it applies to all cold temperatures, because it doesn't.


'zackerly and tig1 keeps winding it out in discussions around 45F purely to promote the obfuscation.

 

[ZeeOSix]

Originally Posted by LoneRanger
This has been cheerfully discussed between us. I think she thinks I'm being overly ocd about the new car.

She's right, unless you're taking about -45F instead of +45F.

 

[Garak]

Originally Posted by KrisZ
That video confuses people more than helps and it obviously continues to confuse you despite numerous explanations as to what was demonstrated in that video.

That being said, if someone wants my blessing to run a 0w-30 HDEO year round, they've got it.

 

[DGXR]

As long as the RPMs have come down to a reasonable level, you can feel comfortable driving away moderately after just a few seconds. But most cars take longer than a few seconds to complete the cold start cycle. Just don't rev it excessively until the engine is near or at full temp. After a cold start, I wait at least 30 seconds and then drive away normally. By the time I reach the on-ramp, I'm near full temperature so it's safe to rev it.
Tribofilm was mentioned in a previous post, tribofilm is bonded to the metal wear surfaces and this is an excellent point to bring up in the conversation. Also there is always a thin film of oil on all the engine parts, even days after shutoff, unless it has been sitting cold and un-driven for 6 months or longer.