MC 5/30 or 5/20 for 6-month(winter) OCI's?

[97tbird]

Hi...

Since I'm starting college soon, and probably not working in the 1st year, my '97 4.6 mod T-bird is going to be driven very little(I WILL drive it on interstate at least once a week to keep it in shape), and I've decided to go to 6-month OCI's, one for winter, and one for summer.
( I haven't seen GC in AZ close to me in NC yet, but I have to check in Raleigh, if I find GC, I would run it year round, and change every 6 months))

Now for winter(at least 5-6 months), I've decided on dealer oil(MC):

(A) would Motorcraft 5/20 or 5/30 be better? or is the difference not big at all?

[Why I'm undecided about MC 5/20: I know what a good oil the MC 5/20 is, BUT I still haven't seen a great UOA on a mod. 4.6 built previous to 2000, which could have different bearing composition from a mod. post 2000 which have been the ones with the good 5/20 UOA's(noone has been able to find out anything about this difference in bearings yet, as far as I know: 1996-97 mod bearing composition is still a mystery!!!./ all my research to find if 97 mods and post 2000 mods have the same bearings were in vain).
AND, those good UOA's mainly came from mod.engines with relatively low miles; mine has 98k miles now.
Otherwise I'd put MC 5/20 without any hesitation]

(B)or do you guys think that the stability of 5/20 compared to 5/30 weighs more than factor that my engine has high miles.?

(C) In general, do these MC oils have the capability to handle 5-6 months of short-trips, including winter months (in NC)?

(D) IF I don't find GC in NC, would MC 10/30 be good enough for 6 SUMMER months(short trips)?
(currently I have M-1 5/40 in, will dump it when it starts getting cold)

would appreciate any help with this decision....
Thanks a lot.

 

[JohnBrowning]

You can find M1 0W30 at almost any Autozone if that is the type of viscosity you want. GC may be great oil but if you can not find I would not worry about it!

 

[pscholte]

97tb,

Didn't Ford publish a list of existing engines that can use the 5W20? If yours is on it and there are no stipulations for temp zones (e.g below 100 degrees, from -20 to 80 etc) that would run afoul of your climate, go for it. I believe in the MC 5W20. Otherwise, I'd mod a little what JB said and I would go with Castrol Startup 5W30; I think it fits your situation VERY WELL. I believe it will handle the six month intervals, isn't THAT expensive, and is apparently easier for you to find than SLX. It's a shame it is so tough for some of you to find...it's great stuff.

 

[97tbird]

quote:

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Originally posted by pscholte:
97tb,

Didn't Ford publish a list of existing engines that can use the 5W20? If yours is on it and there are no stipulations for temp zones (e.g below 100 degrees, from -20 to 80 etc) that would run afoul of your climate, go for it. I believe in the MC 5W20. Otherwise, I'd mod a little what JB said and I would go with Castrol Startup 5W30; I think it fits your situation VERY WELL. I believe it will handle the six month intervals, isn't THAT expensive, and is apparently easier for you to find than SLX. It's a shame it is so tough for some of you to find...it's great stuff.

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Thanks for comments from Pscholte, and JB

Youre' right; Ford does have my engine also listed for 5/20(orig.recomm. oil 5/30); I was only thinking about the bearing material discussions which stated that my engine could be different from the "newer" 4.6 mods....very long discussion which started shortly before/after my UOA with GC(Pb and Cu were a little high; Terry said no worries, Fe was great, and all else, too.).

Anyway, I think I'll try the 5/20 for winter, and keep looking for GC for summer(I still have some hope finding some in AutoZones in Raleigh area...The "small-town" AZ'z in Dunn, Cary, Sanford, Lillington don't have GC

[IF SOEMONE HAS FOUND GC IN NC, PLS LET ME KNOW; I'LL BE VERY THANKFUL]

***Should I be prepared to see some consumption when I switch from M-1 5/40 to MC 5/20? is it too drastic a change in visc. in one step?

Thanks agaian.

 

[Hankrr]

quote:

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Originally posted by JohnBrowning:
You can find M1 0W30 at almost any Autozone if that is the type of viscosity you want. GC may be great oil but if you can not find I would not worry about it!

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Actually none of the autozones around here (Denver, Broomfield area) have had it for quite some time. They replaced it on the shelves with the 0W40 which I tried but didn't like.

Our walmart did the same thing. Only place around here still carrying the 0W30 is K-mart.