Unless the manual has changed, it states to use only regular dino 10W-30 for the first 10K miles and then, if it has stopped using oil, it can be switched to synthetic. I NEVER heard anything about 15W-50!!!!!

 

Look at this thread here.

This thread explains multi-weight oils. It would just make sense to put in an oil that has a higher viscosity in hotter temperature conditions (say running an engine at 9000 rpms). This oil would be fine on warm days for cold starts... but not on cold days for cold starts. I'm suprised that you would have never thought about putting in 15W-50.

 

I use synthetic 5w-30. I have over 10k miles on my car. My thinking for the 5w-30 is that the oil would flow through the engine quicker at start up.

Other than 9k rpm, start up is where most of your engine's wear takes place (most of the oil is in the pan). I figure the sooner the oil flows, the better. Just my 2 cents.

 

[QUOTE]Originally posted by tapout2000
[B]

 

A lot of what I've read here is what an owner "thinks" would be logical oil weight for their car. I would think that the Honda engineers would know a bit more about what is best for our engin and not what the owner thinks.

 

That is 110% correct....Only the Honda Engineers know whats best. After all they designed and spent countless hours performing endurance and durability tests.
This is my guess to why 10W30 is best for the F20C.

1) Reliability and Longevity
2) Optimal Lubrication and protection considering the
design tolerances and clearances.
3) Sustained lubrication at high rpms (9krpm)
4) Meeting LEV Certification. Higher viscosity oills
can increase emissions due to increased fuel economy.
5) Fuel Economy
6) Engine Output. Higher viscosity oils can reduce power output.


Back to RoBD305 question.....Use any name branded 10W30 oil. I used Valvoline All Climate 10W30 in my car but I changed my oil at 2000km, 4000kms, 6000kms and then to synthetic at 9000kms. Am now at 12,500km. Since the 4000km change my engine hasnt consumed any oil unlike some who have reported. Even with synthetic after 3500kms, it hasnt consumed a drop.

Good Luck with your decision

 

I agree with what was said about Castrol GTX and staying away from synthetic for the time being.

Also about viscosity, film strength is more important than viscosity. It is possible to get excellent film strength with lower viscosity. Better flow aids in engine friction surface cooling as well.

Check out this 0W5 oil. I don't think I'd ever use this oil, but will stay with 5-10W30, but it is interesting.

 

Castrol is good