Originally Posted By: earlyre
what you are missing is that for the VAST majority of the time this engine was made (Right here in my town btw), it was spec'd for a 30 weight oil. my mom's 99 taurus, all 5 of the Aerostars dad had as company cars, by buddy's 97 taurus, and his grandma's 96 sable ALL had this engine, and all were spec'd for a 5w30(though i'm pretty sure dad ran 10w30 in the vans). Ford Retro'd the specs for nearly all their vehicles to 5w20 a few yrs ago (mainly to increase fuel economy to meet CAFE standards)
I'm not missing anything. Really, I'm not.
1. just because CAFE standards are the driver of lower-viscosity oils, doens't mean they don't protect as well, or better, than the previously spec'd oils. This false dichotomy simply will not die, but it doesn't mean it's true.
2. A car seeing trips of 4 miles is not going to get up to operating temps. The oil will likely not get past 130F degrees. That would put a 5W20 right about twice as thick as a 20W50 would be at full operating temperatures. If the oil makes it up to 175F (which isn't gonna happen in the first 20 minutes of operation), that will put it right around the thickness of a 20W50.
Again, the ambient temperatures are irrelevant. This engine will be spending all of its time with oil that is much thicker than ideal. There's absolutely no benefit to using a thicker oil than spec'd in this situation--none.
what you are missing is that for the VAST majority of the time this engine was made (Right here in my town btw), it was spec'd for a 30 weight oil. my mom's 99 taurus, all 5 of the Aerostars dad had as company cars, by buddy's 97 taurus, and his grandma's 96 sable ALL had this engine, and all were spec'd for a 5w30(though i'm pretty sure dad ran 10w30 in the vans). Ford Retro'd the specs for nearly all their vehicles to 5w20 a few yrs ago (mainly to increase fuel economy to meet CAFE standards)
I'm not missing anything. Really, I'm not.
1. just because CAFE standards are the driver of lower-viscosity oils, doens't mean they don't protect as well, or better, than the previously spec'd oils. This false dichotomy simply will not die, but it doesn't mean it's true.
2. A car seeing trips of 4 miles is not going to get up to operating temps. The oil will likely not get past 130F degrees. That would put a 5W20 right about twice as thick as a 20W50 would be at full operating temperatures. If the oil makes it up to 175F (which isn't gonna happen in the first 20 minutes of operation), that will put it right around the thickness of a 20W50.
Again, the ambient temperatures are irrelevant. This engine will be spending all of its time with oil that is much thicker than ideal. There's absolutely no benefit to using a thicker oil than spec'd in this situation--none.