Gernby

Isn't intended oil viscosity part of the engine's design? An engine with high tolerances and small clearances would require a liter weight oil, and vice versa, right? It seems to me that unless Honda redesigns every engine in its lineup for '04, they will not change the recommendation for all to use such a lite oil.

Prolene

It will be interesting to see if this Honda dealer employee is correct. That Honda's 0w-20 is on the shelves is significant, imo.

wickerbill

I don't know why there's any debate. We all know that whatever a Honda dealership employee says is fact.

Road Rage

OK, here is my take:

0w20 or 5w20 are done for two reasons:
better fuel mileage, including offsetting effects of Pilots on CAFE; lower emissions to be "green" . They do not provide the protection for longevity, esp. in hot climates.

Too high a viscosity can prevent oil from reaching very tight toleranced areas, but I dubt that the diff between a 20 wt and a 30 wt would matter unless the engine are now being made with vastly tighter tolerances. Even though, remember that recent BMW's came with 5w40 synoil, and were later switched to 10w60! Doubt they rebuilt the engines when they changed that recommendation! They probably found wear rates were too high.

10w30, even in mineral oil, is good to about 0degF. If you driive day to day in very cold climates, go to a 0,5,10w30 synoil. I plan to use 10w30 Amsoil synoil, but I am in a temperate climate, garage never drops below 55 degF, etc.

Remember that a 0 or 5w30 has the same protection at high temps as a 10w30. Synoils have naturally wide viscosity range, and do not use much, if any, Viscosity Improver to ensure shear stability and high-temp protection. Vis improvers are actually polymers, which change shape (and properties) as temperature changes.

Ever wondered why a squeaking fan belt stops when it heats up? There are polymers in the rubber which actually shrink as temps increase, ensuring a good fit.