Mobil 1 shear issues

[Heywood_6078]

I recently had my silverado serviced at the dealer after using Mobil 1 and ac delco filter for the past couple years. I notice my oil pressure isn’t running as low at hot idle after towing in the summer. Not sure what kind they used but I can’t imagine it would be anything other then bulk oil. Does Mobil 1 have issues with shearing or something I’m not aware of?

Amsoil claims to be better protecting shearing although, the test are done by
Amsoil themselves. For whatever that's worth.
https://blog.amsoil.com/amsoil-vs-mobil-1-performance/

 

[kschachn]

Mechanical shear resistance in a multi-grade oil is entirely dependent on the quality of the VII. So if Amsoil uses a higher quality and more shear resistant VII then it is possible. But on the other hand very few passenger car engines have a problem with shear, but some do. It's mostly fuel dilution that causes viscosity deviation.

 

[ZeeOSix]

Mechanical shear resistance in a multi-grade oil is entirely dependent on the quality of the VII. So if Amsoil uses a higher quality and more shear resistant VII then it is possible. But on the other hand very few passenger car engines have a problem with shear, but some do. It's mostly fuel dilution that causes viscosity deviation.

Seems engines with lots of cam chains (like a DOHC Ford Coyote) mechanically shear oil more than engines without lots of cam chains.

 

[buster]

Amsoil claims to be better protecting shearing although, the test are done by
Amsoil themselves. For whatever that's worth.
https://blog.amsoil.com/amsoil-vs-mobil-1-performance/

From what I've seen on here through UOA's, Amsoil and Castrol EDGE do seem to hold their viscosity a bit better than Mobil 1 (pre-Triple Action). It's pretty marginal though in the grand scheme of things.

 

[userfriendly]

There might be a slight drop in viscosity from the Dexos-1 gen 2 vs gen 3 products, as it appears from the Lubrizol spider graph
a trade of wear protection for fuel economy.

www.gmdexos.com

 

[flash7210]

Seems engines with lots of cam chains (like a DOHC Ford Coyote) mechanically shear oil more than engines without lots of cam chains.

But is that because of the chains?
The chains don't require much lube.
Or is it because the coyote has 4 camshafts?

 

[kschachn]

But is that because of the chains?
The chains don't require much lube.
Or is it because the coyote has 4 camshafts?

Camshaft lobes won't cause VII permanent shearing like that.

 

[ZeeOSix]

But is that because of the chains?
The chains don't require much lube.
Or is it because the coyote has 4 camshafts?

Questions and the answers from Pennzoil experts. See questions 1 thru 3.

https://bobistheoilguy.com/valve-train-and-timing-chain-wear/

 

[flash7210]

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