I currently have 3 cars and would like to standardize on an oil and weight to simplify my purchasing. I recently switched to Mobil 1 for all three, but I'm using 2 differnt weights.
I'm currently using 5w30 in 2 of them and 10w30 in the other.
Here's the vital statistics:
Summer: 85-110, mostly 90-95 degrees.
Winter: 20-45, rarely below freezing
Car 1: '02 Ford Explorer SOHC V6 (Odometer 3600) - Ford recommends 5w30, 3000 or 5000 mile drain intervals.
Car 2: '93 Toyota Camry V6 - (Odometer 99,000) Toyota recommends 10w30 (I think) with 3000, 5000 mile drain intervals.
Car 3: '91 Ford Explorer OHV 4.0 V6. (Odometer 88,000) Ford recommends 10w30 with 3000, 5000 mile drain intervals.
Est. Annual Mileages
Car1: 12,000
Car2: 10,000
Car3: 1500
If I want to go with a universal oil then 5w30 is it because of the warantee on the new vehicle. If a 5w30 will work well in the others then I have no problem with that. Is 5w30 M1 SS good for '91 explorer even though it asks for 5w30? Based upon the oil comparison chart recently posted on this site, the viscosity at 100C degrees seems a bit lower (thinner) than the other oils in the same weight range. But the 10w30 and 5w30 M1 look almost identical at temperature so I don't see any big advantage to running 10w30 M1 Vs 5w30 M1.
Is the viscosity at 100C degrees a good indication of the lubrication properties at operating temperatures (higher being better)?
Would appreciate feedback and suggestions