just wondering what engine oil is best for hot climate ? like over 90 F....
heard that heavier than 10w30 engine oil is normally used.

thanks

 

Conventional oil 10W30, synthetic oil 5W40 or 0W40 or 0W30. I prefer 0Wxx oils because their base stocks are mostly group IV/V.

 

I am researching the exact same question, and below is what I found:

Here's a three-line table to give you an idea where typical engine oils are used:
Oil type Typically used in....
-5W-30 Cooler climates, like Sweden or Canada
-10W-40 Temperate climates, like England
-15W-50 Hot climates, like Italy, Spain, Egypt

Source: http://www.carbibles.com/viscosity.html

Who should use a synthetic oil? The premium-priced oil is best for:

-Turbocharged or supercharged engines
-Performance or high output engines
-Vehicles used for towing (especially during hot weather)
-Vehicles that are operated in extremely cold or hot climates
-Anyone who wants the ultimate in lubrication and protection

Source: http://autos.yahoo.com/maintain/repairqa/a.../ques120_1.html

I live in Oman and in the winter:
daytime lows around 20C/68F,
daytime highs 30C/86F,
in the summer:
daytime lows around 30C/86F,
daytime highs 50C/122F.

Based on the information from the above sources, for hot climates synthetic oil is recommended over dino oil. Moreover when I tried to find the grade recommended in the S2000 user manual (10W30), I couldn't find it. The closest I found was 10W40. I ended up buying Shell Helix Ultra 15W50.

Please let me know if anyone else info on this question.

 

You're missing the point slightly. The S2000 has a very well controlled and highly effective cooling system. So even if the temperature outside is 90F the engine is going to maintain roughly the same temperature. The same goes for winter temperatures, the car's cooling system is designed to keep things at an operating temperature of around 100C and it does this quite well.

This will NOT be the case if you're on a track all the time. But if you're daily driving the car then stick with what the manual recommends. I personally would keep a 30wt oil in the car, get a good 0w30 if you can find it.

 

Stick with what Honda recommends, unless you have a VERY GOOD reason to change (like a measured reduction in lubrication effecency on the track).

 

https://www.s2ki.com/forums/index.php?showtopic=195574

 

FWIW castrol syntec 0W-30, the stuff made in germany I.E. "german castrol" is on the thick side of 30W oil, You might consider it. I went 6K+ OCI last summer. Plus it seemed to quiet down my engine some.

 

Gaja in Dubai provided the following information: "The dealer here in Dubai uses 20W50 Honda motor oil on S2000. May be it is same in Oman. Just check with their parts store you can buy a can from them."

Dubai has pretty much the same climate that I described for Oman.