Has anyone else noticed that in the oil chart in the owner's manual, that 0 and 5W30 have arrows that extend up into the higher temperature ranges, just like 10W30 and 10W40????

Do you think Honda is seriously recommending these as year round/all season oils??? (And, the really heavy hot weather oils, like 20W40 and 20W50 are gone.)

This seems to be a departure from the "old school" days. They must have put small oil gallies (which requier thinner oils to flow well) and tighter tolerances in these engines. Is this the first of a new generation of Honda engines?

I would be interested to see the oil chart, of the newly redesigned engine in CRF450R dirt bike! Perhaps we will see this fuel injected minimalist engine in a quad some day???

 

a 5w-30 and a 10w-30 act exactly the same at operating temperature
same for a 10w-40 and 20w-40

 

<div class="FTQUOTE"><begin quote>Originally posted by: snorulz

a 5w-30 and a 10w-30 act exactly the same at operating temperature

same for a 10w-40 and 20w-40</end quote></div>

This may be generally correct, but is also too simplistic an explaination!

It takes more VII's (Viscosity Index Improvers), to make for example a 0 weight oil behave as a 30 weight oil when at operating temperature, than it will to make a 10 weight oil behave as a 30 weight when it is at operating temperature. VII's are one of the most degradable additives in your oil, so you want to keep the amount as low as possible.

So, it is always best to keep the range between the lower number on your oil as close to the higher number as possible, but of course taking into account the lowest cold starting temperature you will encounter.

Also....there are differences between a 10W40 (a "light 40") and a 20W40 (a "heavy 40"), based on film strength....so again your explaination is overly simplistic!

This issue intrigues me, becasue I live in So. Calif. where the desert temps are well over 100 degrees, every day in summer. I don't think Honda really expects me to run a 0W30 oil in those conditions, but some unthinking person might look at the oil chart and make that mistake.....