Kendall 10W30 thinner than their 5W30?

[LoneRanger]

Looking at the Product Data Sheet for their Full Synthetic and their Synthetic Blend, it appears that their 10W30 has thinner viscosity than their 5W30, for both oils. Would this be due to more viscosity index improvers in the 5W? Kendall GT-1 Full Synthetic PDS Kendall GT-1 Synthetic Blend PDS

 

[KCJeep]

The full syn looks backwards to me, most 5w30's don't make a cst@40 of 58 much less a 10w30. I think the synblend is right, yes it would be the VI's but the 10w30 would be more shear resistant so it would likely be thicker as you got into the OCI, JMO. Good oil, Autozone has it on sale I want to try some myself.

 

[CATERHAM]

Actually your're mistaken. You're comparing the kinematic spec's and you should be comparing the HTHSV and VI. Their 10W-30 has a HTHSV of 3.1cP vs 3.0cP for the 5W-30. That in conjunction with the higher 167 VI of the 5W-30 vs only 154 for the 10W-30 makes it a significantly lighter oil at all oil temp's.

 

[LoneRanger]

This is why I ask questions, to learn. :~)

 

[CATERHAM]

It's a common mistake that 99% of BITOGer's and others make.

 

[KCJeep]

Thanks CATERHAM I've learned a bunch from you on here too, appreciate it.

 

[45ACP]

If you know the HTHS which is the most important spec of an oil (correlates it to SAE grades,) can you virtually ignore the VI?

 

[CATERHAM]

Originally Posted By: 45ACP

If you know the HTHS which is the most important spec of an oil (correlates it to SAE grades,) can you virtually ignore the VI?

What you can ignore are the individual KV spec's. The viscosity index itself is second only to HTHSV is comparing the operational viscosities of different oils.

 

[Ken2]

Ranger Both are within the 30 wt viscosity spec range, and a difference of 0.2 cSt is not meaningful. The spec range is 9.3 to 12.49 centiStokes @ 100°C. The high shear rate viscosity @ 150°C for a 30 wt is anything above 2.9 mPa. You made no mistake. The real test of any oil is to check the conditions of the oil after service, say 5000 miles, and see how it compares to the specs. The initial specs may have no relation to how the aged oil protects your engine. The API and ILSAC tests of the oil do run it to test limits of specified hours in test engines to provide aged oil specs. http://www.infineum.com/Documents/API/AP...Oils%202010.pdf

 

[CATERHAM]

Ken2, this has nothing to do with new oil verses used oil. What you don't understand is that the simply kinematic viscosity measure doesn't take into account how different oil chemistries behave in a operating IC engine, particularly oils with different polymer levels. The HTHSV measure does, and since the change in viscosity at higher temperature levels is virtually linear, the HTHSV spec' trumps the KV100 spec' when comparing the operational viscosities of different oils. This point was discussed in detail in the following thread: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2276634&page=1