which factor weighs more? MC 5/30 sheer or being syn blend?

[97tbird]

Assuming one was to choose between MC 5w30 and
MC 10/30 for 6 months of winter (in NC) in a HIGH mileage 4.6L mod., there are some factors to be considered between these two:

1) Normally, from what I've learned MC 10/30 is more sheer stable than MC 5/30,
BUT: now the MC 5w30 is a syn.blend: does this make it better or as stable as the "regular" MC 10/30? (consider also that 5W cold-start is better than 10/30...?)

2) or is MC 10/30 STILL better due to the smaller visc.spread and better sheer stability?

Which factor(s) weigh more, and in the end, which oil is "better" for winter use?

(or is MC 5/20 better than both 5w30 and 10/30?)

Advice will be much appreciated...
Thanks.

 

[Al]

Yea-its probably a tossup. But I thought the 5w30 was the blend. I'm probably wrong.

 

[C4Dave]

Even if it shears to a 20 weight, the 4.6L motor does very well on 20 weight.

 

[seotaji]

5w30 will be just fine.

It doesn't get that cold here, but quick flowing lube is always a good thing.

 

[Whimsey]

With the new Motorcraft 5w30 saying it's now made from hydrocracked/synthetic base oils versus the 10w30 which does not have any synthetic base oil in it I would tend to believe that the 5w30 would not shear as much as the 10w30. Besides with your Triton motor you want the quickest cold pumping oil to minimize start up wear. With the new updated Motorcraft 5w30 it might even be a toss up between the new 5w30 and the 5W-20 as far as lack of shearing. We'll need to see some used oil analysis.

Whimsey

 

[97tbird]

Thanks to all the replies...

So, I think I'm going with the MC 5/30...this oil does sound good for my 4.6L mod.

However, I will be switching from M-1 truck/suv 5w/40 to MC 5/30; so i'm expecting some oil use due to the jump from 40 to 30 weight.
In this case I think i'll use MC 10/30 or 10/40 to top it up to help the visc. a little over my planned 6-month OCI with the MC 5/30.

I'm really excited about this new plan of mine...

what do you guys think about using MC 10/30 or 10/40 to top up, in case there's a consumption isuue? which one is better for that purpose?

Thanks again.