5-30 VS 10-30

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Mar 2, 2003
So Cal
I run Mobil 1 5k miles in both my F150 5.4 and my toyota avalon v6. the 150 calls for 5-20 and the toy 5-30. Winter gets down to 35F and Summer up to 110F. Can the 10-30 Go down to 30F ? Its nice to just buy 1 oil to run in everything but of course I want to make sure I'm ok for 5k. Just looking for some general guidance. Thanks.......
I would go with Mobil 1 5w-30 in the F150 since it calls for the thin 5w-20. Mobil 1 5w-30 is on the thin side of 30 and would give better protection than the 5w-20. If you feel compelled to stick with the 5w-20 for warranty issues, the Motorcraft brand made by ConocoPhillips has produced some good UOAs.

For the Avalon in the warm climate, go with the Mobil 1 10w-30. It is their most shear stable viscosity.

Is the Avalon the 3.0 V6 sludge beast?

[ November 30, 2003, 10:13 PM: Message edited by: John in the ATL ]
yeah its the sludge-omatic. Did an auto rx at 50k. I also continue the 3 oz dose at oil changes. I'm at 55k now. I'm gonna run these cars to 200k so i figure 5k changes with auto rx every 50k should keep em goin strong.
I'd use the 5W-30. There doesn't seem the be a shearing problem with it any longer if the recent UOA's are any indication so why not go for the oil that's thinner at startup...
I have used Mobil 1 10W-30 down to at least -17 F with no problems. If I were using Mobil 1-Id run the 10W-30 in all three vehicles. And if I felt guilty I might ad a quart or two of the 0W-20 in the Ford (If I remembered it-if not so what
Mobil 1 10W-30 has a much lower cold viscosity than Amsoil 5W-30, Redline 5W-30 and all high-mileage 5W-30. The difference at 35F is absolutely negligible for your engine and if you want to stay with 10W-30 year-round you will be fine. Period.
My Haynes manual for the 1980-1996 Ford pickups says straight 30 weight is good down to 40F, 20w40 and 20w50 are good down to 20F, 15w40 is good down to 10F, and 10w30 and 10w40 are good down to zero F. It also shows 5w30 is good only up to 60F. I am running 10w40 in my '95 F150 in Detroit. It does not get below zero much here. I might run 15w40 if I lived where you are, but I need to 40 to maintain spec oil pressure, you presumably don't, so a 10w30 is probably great for you.
I chose 10w30 M1 for my 4.6L F150 for year 'round Seattle driving (20F-95F temps), I think it would be fine for you too, after much reading I determined 10w30 M1 is superior to 5w30, and fine for my climate.
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