Wow!!! You guys are the best. Thanks for all the info from my earlier post. Since my last reply, I found the Viscosity Grade Chart off of Bob's Home Page. Reviewing this chart open my eyes. If I quote something wrong, please correct me. From other posts, Moble One 5w30 has a Kinematic Viscosity of 9.7 cSt@100Deg C, Ford Motorcraft has a viscosity of 8.8 on the same scale. From Bob's Chart, the breaking point between 20 wt. and 30 wt. is 9.3.
Hmmmm, If my stated values are correct, M1 5w30 is a very thin 30 wt., darn near a 20 wt. No suprises, I all ready knew this from reading old posts. What I didn't realize was that the Motorcraft 5w20 was way high on the 20 wt. Bob' chart shows 20 wt. from 5.6- 9.29.
Folks, this dog ain't going to hunt. There just doesn't seem to be a significant difference between the 2 oils at operating temperture. I wish I could compare cold weather flowability of the Motorcraft 5w20 to M1 5w30 or M1 0w30.
By knowing how the Motorcraft 5w20 flows at cold temps, and since we know the viscosity warm, we should be able to gain more insight into Ford's thinking when they speced the 5w20.
Just looking at the viscosity numbers and the chart, and by using common sense, I feel more confident that the car buyer has been suckered. The upper viscosity values are close and surly M1 5w30 will flow better at start-up then any dino or blend 5w20. I realize that other 30 wt. oil are higher on the scale than M1 5w30, but it sure looks like Ford and maybe Honda could have allowed the use of Moble One 5w30 and any other 5w30 oils that are close to the M1 visocity. Is there an obvious reason why Ford couldn't have save all the money spent on developing their 5w20 and simply speced a synthetic oil like the M1 5w30 and still got the CAFE boost.
I don't mean to sound like a M1 5w30 salesman, I am currently using it in a 97 Towncar, mainly because I get it in 5-quart jugs for $17.84 ? at Wal-mart and they always have it.From what I have read, it seems to be popular and has good wear numbers, but not the best for extended intervals.
Can someone show me where my logic is incorrect or do you agree my thoughts have merit. As always, Your comments and feedback are appreciated. Fred