Interesting...GTX 10W-40 3.6 HT/HS

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I know this isn't new or important news, but I just found it interesting.

It appears from this 2015 PDS that Castrol GTX 10W-40 has a HT/HS value of 3.6, which technically makes it an A3-level oil.

https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/A9EED664E7A92C4E80257EC60063BBB1/$File/BPXE-A2ZRG9.pdf

I found this interesting, b/c 'normal' 10W-40's are 'minimum 2.9' HT/HS.

GTX oil seems to have a fairly stout add-pack, so this 10W-40 PCMO is more like a HDEO than not. Might be a good option for those looking for a stouter oil.
 
Originally Posted By: addyguy
I found this interesting, b/c 'normal' 10W-40's are 'minimum 2.9' HT/HS.

This hasn't been true for quite some time now.

SAE J300 was revised a number of years ago. Any 10w-40 oil has to have HT/HS of at least 3.5 cP...

SAEJ3002009.JPG
 
Huh...I had no idea!

I thought 15W-40's had to be minimum 3.5; but that 10W-40's still counted as PCMO's, so they only had to meet 2.9, and that is why 15W-40 HDEO's are so much stouter - they aren't 'allowed' to shear down as much.

Thanks!
 
I think Castrol for some reason lists the minimum HTHS for the grade instead of the actual HTHS.
I think i saw a datasheet where Castrol TWS/Edge 10W-60 was listed as having a 3.7 HTHS.
 
The old style 10w-40 examples were the reason GM historically forbade them. There's not a lot of point buying a 10w-40 with an HTHS of around 3 when every ILSAC 5w-30 and 10w-30 does the same.
 
Originally Posted By: Garak
The old style 10w-40 examples were the reason GM historically forbade them. There's not a lot of point buying a 10w-40 with an HTHS of around 3 when every ILSAC 5w-30 and 10w-30 does the same.


Not necessarily so. Many engines do not achieve 150C oil temps, and therefore, at more normal temps, the more viscous 40 viscosity oil may be beneficial under certain high load conditions. High boost turbocharged engines are great examples. There are a whole bunch of us modifying our modern turbocharged engines to impressive power levels. The ones that survive choose a good oil.

Here is a 3.5L Ecoboost in an F150, that originally produced 300RWHP:

Dyno-Data-F150_450.jpg
 
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That's true, but HTHS is still HTHS, and it doesn't turn on and off at 150 C. I still don't see a point of a 3.0 HTHS 10w-40 when I can do the same with a 10w-30 or 5w-30; and, if I need a 40, I'd be looking for the HTHS. HTHS is more important than KV; dynamic and kinematic viscosity are simply not the same things. The Germans spec by HTHS for a reason, and it's similar with API diesels. And, if I did need a higher KV and SAE grade, 10w-40, particularly an old school one, wouldn't be my choice.

Would one really want a sloppy, old school, VII loaded 10w-40 in a turbo? There are so many better choices out there.
 
I thought that was what made 10W-40 PCMO a pointless choice - they had the same HT/HS as a 10W-30, so why bother with them.

Also thought this is what caused the 1970's 'sludging epidemic' - piles of cheap VII's in 10W-40's broke down in the heat and turned to black goop!

Thought this was still basically the case - didn't realize they had been updated.
 
Just for the record, it's nigh on impossible possible to make a 10W40 with anything like as low an HTHS as 2.9. The lower KV100 limit of a 10W40 is 12.5 min. Generally this equates to an HTHS of about 3.8 if you use OCP VI and a bit lower (say 3.5) if you use HSD VII.

Having said that, virtually no commercial 10W40 will have a KV100 that's anywhere near 12.5 and it will almost certainly be higher. In Europe, the KO 30 Cycle shear test and the need to stay in grade will push the KV100 to around 14.3-ish and the HTHS will rise in line with this. In the US, usually the Sequence VIII 'stripped viscosity' requirement will push the fresh oil KV100 up (not sure by how much as 10W40 is rare in the US but I'd guess to around 13.3-ish) again with an associated jump in HTHS.
 
Joe, at one time, we used to have a few 10w-40 examples that could meet ILSAC fuel economy requirements, and were so certified. That was before the SAEJ300 updates, too. Petro-Canada even referenced that some time ago in their lubricant guide.
 
Originally Posted By: FordCapriDriver
I think Castrol for some reason lists the minimum HTHS for the grade instead of the actual HTHS.
I think i saw a datasheet where Castrol TWS/Edge 10W-60 was listed as having a 3.7 HTHS.


Sometimes Castrol give real numbers on their product sheets, not the min J300 numbers (which is a bad habit of theirs).

Castrol Edge 10W-60 has a HTHS of 5.1 cP

Here our Castrol GTX 15W-40 is API SN and ACEA A3/B3 and has a HTHS of 3.95 cP, well above the min requirement.

Castrol Edge 5W-40 (SN, A3/B4) has a HTHS of 3.8 cP
 
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