Engine oil question.

[NickAdams]

Great . . . thanks

 

[PoTreeBoy]

My L35 and Ford both call for 10w30, which is pretty limited here in diesel oil. I've used mostly 15w40 T6 in both lately. But I did put 5w40 T6 in the Kubota once and could tell it cranked noticeably faster. I saw 10w30 T6 for the first time at Walmart the other day and was on the verge of picking some up. But I remembered I have some 5w40 and 15w40 already sitting around, and I've been thinking about mixing them 50/50 to get 10w40. I like a little higher hot viscosity since Katy's got a few hours on her.
I suppose @TheOldHokie is going to tell me that's not a good idea?

 

[TheOldHokie]

1. My L35 and Ford both call for 10w30, which is pretty limited here in diesel oil. I've used mostly 15w40 T6 in both lately. But I did put 5w40 T6 in the Kubota once and could tell it cranked noticeably faster. I saw 10w30 T6 for the first time at Walmart the other day and was on the verge of picking some up. But I remembered I have some 5w40 and 15w40 already sitting around, and I've been thinking about mixing them 50/50 to get 10w40. I like a little higher hot viscosity since Katy's got a few hours on her.

I suppose @TheOldHokie is going to tell me that's not a good idea?

Almost nobody makes 10W40 anymore.

It was a legacy formulation from before the advent of synthetics and used conventiinal base stocks with high treat rates of viscosity index improvers. The high treat rate caused rapid viscosity loss due to shear. In particular its high temp high shear ,(HTHS) viscosity was very poor. Thats why 15W40 was the go to grade for heavy duty diesel oil.

Today you get get better cold and hot performance with a 5W40 synthetic - e.g. wider grade spread with fewer VI improvers. As a result 10W40 pretty much went the way of the dodo.

Dan

 

[lynnmor]

B2400 in Virginia - I usually use Rotella T4 15w-40. I bought T5 15W-40 Synthetic - ok to use? Thoughts? Thanks

The T5 is a synthetic blend, only the T6 is full synthetic.