Decoding 10W30 vs 10W40 A Comprehensive Comparison for Car Enthusiasts

10W30 and 10W40 are made from the same base (assuming we are comparing oils from one manufacturer) with different amounts or types of polymers ( ... Not so much for the heat reasons, but because the oil brand I purchase is only available in 10w40 weight. So short answer, there is no ... Researching which oil I'm going to use on my '12 1KRR, and page 138 of the manual says 10W-30 JASO MA, but goes on to list Honda GN4.. Well, which is it? GN4 is 10w30 is thinner than 15w40, meaning it flows through the engine more easily but doesn't have as high of a film strength as 15w40. ... 10W-30 API SL. FULLY SYNTHETIC 0W-20 API SN. SERVICE CENTRE & HIGHSTREET. Availability: 3L & 3.5L 3L 3.5L. Excellent wear protection with enhanced antioxidant ... RECOMMENDED ENGINE OIL QUANTITY ; Super Splendor 125, Super Splendor S.V, BS-IV, 10W30 SL MA2, 0.95 litre ; Xpulse, Xpulse 200, BS-IV, 10W30 SL MA2, 1.20 litres ... The only time you have to even consider going to thinner oil when it gets cold is if the starter can't turn over the motor fast enough to start the motor. A 10W30 is a 10 weight when cold and a 30 weight when hot, but a hot 30 weight is still a hell of a lot thinner than a cold 10 weight. Oil 10W30 Vs 10W40 Texas Impreza Club Forum -- TXIC. What would you expect the Honda rep to say? ;) 10W-40 is perfectly fine and comes in many brands.