Does it really matter how hot it is outside?

[Errtt]

Originally Posted By: demarpaint
Originally Posted By: Fallguy
Originally Posted By: ChuckBerry
Originally Posted By: gfh77665
Nice try, really, but no. Read the following:

http://bestsyntheticoil.com/dealers/amsoil/5w20-cafe.shtml


Sez Amsoil.


The bottom line is that the thinner the oil, the faster your oil pump can get it to the top of the engine during cold starts, and the more damage is reduced. You can use 5W30, but you're wearing out your valvetrain faster than you will with 5W20.

http://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2212266#Post2212266


During cold starts is one 5w is different than another 5w just because the 20-30 grade number is different? Thought the standard for 5w was the same and not dictated by the top number.

Now 30 grade may note flow as well through tighter bearing clearances etc and be a problem, understand that but at cold start they should be equal.

On a same engine is it indeed speced for different grade in different country?


There are certain 5W-xx oils that flow better than other 5W-xx oils while cold. I've found with my pre-luber this to be true over the years with different brands of oil both conventional and synthetic. I've also found with 5w20 vs 5W30 that the 5W20 got moving a bit faster when cold. Having a pre-luber you can really tell the difference, with an engine oil pump the difference isn't as noticeble. JMO


How are you able to tell the difference with a pre-luber?
You can't see the oil inside the engine so I'm trying to understand this, how to determine via pre-luber you can really tell the difference and not so much with the engine oil pump.

 

[FZ1]

I don't agree with the explanation the dealer gave you. Thicker oil is going to tend to run hotter. That's why I run only 5-20 spec synthetic oil over here in Texas. Synthetic tends to run cooler and Thinner tends to run cooler. I like Mobil 1 Extended Performance about 5,000 miles or 6 months. 111,000 Bass boat towing miles on my Accord V6 and engine runs like new.

 

[Pablo]

Originally Posted By: ChuckBerry
Originally Posted By: gfh77665
Nice try, really, but no. Read the following:

http://bestsyntheticoil.com/dealers/amsoil/5w20-cafe.shtml


Sez Amsoil.


I just would like the record to reflect this is not the official Amsoil position. This is just a dealer's opinion.

Run the viscosity recommended.

 

[4ever4d]

Personally i'll not be convinced that Ford,Honda,nor Chrysler would recommend a 5-20 engine oil based on CAFE and not be confident that it will also protect internal engine parts as well as any other grade of pcmo.There was too much testing done just for CAFE applications alone.As for the op the very minor differences between a 5-20 and a 5-30 would not amount to anything based on ambient temps as most 30's shear to a near 20 and most 20's remain fairly stable.If it's that big of an issue go to a 40 or even a 50 in high ambient temps.

 

[flatlandtacoma]

Originally Posted By: Fallguy
During cold starts is one 5w is different than another 5w just because the 20-30 grade number is different? Thought the standard for 5w was the same and not dictated by the top number.


True but remember 5w is a range of viscosities, not a single viscosity. A typical 5w20 is thinner than a typical 5w30 at pretty much any temperature higher than -30C.

 

[river_rat]

The 20 or 30 weight makes little difference in wear, it is the 150ºC HTHS viscosity.
That does tend to be higher in the 30 weight, but not necessarily so. In any event, the HTHS for API licenced 20 weight in the US must be at least 2.6, and 2.9 for 30 weight. There is little difference in wear between these two viscosities in real engines according to SAE white papers.

As Caterham pointed out with a lenghty experiment, the oil pressure, and therefore flow at any given temperature, appears to be related almost exclusively to HTHS as well.
As for me, I see almost no difference in pressure with a given oil--winter or summer when it reaches peak engine temperature under a given driving condition.
(air cooled engines excluded)

 

[FZ1]

That's an interesting/good point. Thanks,man.
Originally Posted By: flatlandtacoma
Originally Posted By: Fallguy
During cold starts is one 5w is different than another 5w just because the 20-30 grade number is different? Thought the standard for 5w was the same and not dictated by the top number.


True but remember 5w is a range of viscosities, not a single viscosity. A typical 5w20 is thinner than a typical 5w30 at pretty much any temperature higher than -30C.

 

[virginoil]

Originally Posted By: FL-400S
My 3 older cars take 5w30. The newest (09 vibe) takes 5w20. I had the free oil changes from pontiac dealer last year, and they put in 5w30, ......................

I had it changed in December (castrol 5w30) and on a recent road trip got 32 mpg (rated 31, I tend to drive the speed limit). ..................................

I'll tend to use syn so I dont have to worry about it as often. Driven about 50% town and 50% highway.


Gentlemen a small point I think has been missed.

Why fuss about the 5w30 when the vehicle is getting better fuel economy with it ie 32mpg compared to 31mpg. Stick with the 5w30 unless the OEM strictly forbids use of any other grade.

Can't be that bad and can't be too thick if the mpg has improved.

 

[demarpaint]

Originally Posted By: Errtt

How are you able to tell the difference with a pre-luber?
You can't see the oil inside the engine so I'm trying to understand this, how to determine via pre-luber you can really tell the difference and not so much with the engine oil pump.


It is very easy to tell the difference with my Pre-luber. First off it is an electric oil pump which takes oil from the pan, and feeds it into the oil sending unit opening on the engine via a Tee fitting. The pump is small and very sensitive to "oil thickness". Pennzoil Conventional 5w30 vs 5W30 PP takes longer to get the oil pressure gauge moving, and the difference can be detected in temps as warm as about 45*F. At about 20*F it can take the pump almost twice as long to start pressurizing the oil system. The lower the temps the longer that little pump takes to pressurize the system. When you dip below 0*F the pump really labors. Synthetic oil flows faster and easier. You can also tell the difference between a 0W30 and a 5w30 synthetic.

Now an engine oil pump works faster and more efficiently. Based on my observations if it is taking the pre-luber longer, the oil pump is taking longer. Maybe only a fraction of a second, but over 1000's of cold starts I'm willing to bet it adds up.

If you read Dr. Haas's articles he covers this, even in warmer climates there are slight differences between conventional and synthetic oils and 0w-xx and 5W-xx oils. Does it matter? Probably, it depends on how long you keep a car. JMO