What is HTHS ?

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HTHS on the Redline page is like a 3.8 for their 5/30 I was considering using. So in essence the higher the number the better? MPG's aside. Just from a "wear prospective". Am I correct in saying that a higher number nets less wear?
 
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Lets say better protection instead of wear.

HT/HS or "High Temperature/High Shear" (ASTM D-4683) is an rating that determines the oils stability in a high temperature, high stress conditions. The oil's ability to withstand shearing and tearing is very important especially in a high RPM engine. The oil's ability to protect bearings, cylinder walls and rings, connecting rod bearings, main bearings, cam lobes and lifters, etc. is vital to an engine. For an oil to pass the ASTM D-4683, an oil must have a protective viscosity of 2.9 cP at 302 degrees F. The HIGHER the number the better!

I think for most street engines driven as such it makes little difference.
 
With a modern Turbo Diesel, where the emission system protection is such a big deal, I wonder if it would be really wise to use an oil that is a VW 507 spec? Meaning, above 3.5 HTHS and low levels of ZDDP.....?

Here is what I will be using......

Picture001-5.jpg
 
Originally Posted By: 62Lincoln
I think LL04 is BMW's spec for its turbo diesel, not LL03. Not sure if it matters on the Castrol, just wanted to mention this to you.


That's a different "LL". It's the name, not a spec in this case.

SLX LL03 is VW 504.00/507.00, ACEA A3/B4/C3.
 
Can I use oil with high HTHS in engine that require low HTHS?
Is this better for that engine?
 
Anybody?

My owner's manual says ACEA B1 or API CF-4.

ACEA B1 is oil with low hths, but spec API CF-4 have many oils which have also spec ACEA B4 - high hths.
 
Originally Posted By: Maxx
Can I use oil with high HTHS in engine that require low HTHS?
Is this better for that engine?


Yes.
 
Originally Posted By: ZZman
Lets say better protection instead of wear.

HT/HS or "High Temperature/High Shear" (ASTM D-4683) is an rating that determines the oils stability in a high temperature, high stress conditions. The oil's ability to withstand shearing and tearing is very important especially in a high RPM engine. The oil's ability to protect bearings, cylinder walls and rings, connecting rod bearings, main bearings, cam lobes and lifters, etc. is vital to an engine. For an oil to pass the ASTM D-4683, an oil must have a protective viscosity of 2.9 cP at 302 degrees F. The HIGHER the number the better!

I think for most street engines driven as such it makes little difference.



Like most on BITOG, you don't understand what HTHS viscosity is.
"The HIGHER the number the better" is the same as saying a 40wt oil is better than a 30wt which is of course not true.

Put simply HTHS is a measure of viscosity that accurately replicates the actual viscosity of an oil in an operating engine under stress (pressure) taken at 150C.
The following post explains further:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2000048&page=1
 
Hello,
I'd GUESS that this is to get a specific cP in the bearings and other places under pressure in spite of what base oil and viscosity grades you are using. In other words, just because a 5W-40 pumps as well as a 5W-20 in cold weather, they don't want the 4.4 cP that the 5W-40 probably gives you in the HTHS.
 
Annabelle, welcome to BITOG!

A 5W-40 will NOT pump anywhere near as well as a 5W-20 in cold weather.
The SAE grading system is a range and the requirement for a 5W oil is very broad.
If you want to compare the the cold pumping performance of a particular oil it's best to pull up the info' from the companies Product Data Sheet.
 
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