Lower engine temps? 15w40 to 5w40

[SZR48207]

In my SV650 I have run Rotella T 15w40 for most of its life since it's a well established JASO MA oil. However I was able to buy some Rotella T6 5w40 for a crazy deal last year and just did my spring oil change with it.

Initial impressions are that nothing feels any different. Shifting may be marginally smoother.

However it seems like the engine runs a bit cooler in stop and go traffic now. There is a particular overpass in my area that turns into a "inch forward every 4 seconds for 5 minutes" during rush hour situation and the bike only got up to around 205*F where in the past it would have been up near 215*F.

Is this possible? Maybe I'm just misremembering?

 

[Dylan1303]

On my yzf600r p.o. Used castrol blend and i switched to amsoil. Only thing i noticed was a cooler temp on my bike in stop in go traffic. Some one told me awhile ago that syn oil dispenses heat better.

 

[faltic]

My 07 Ninja 250 runs 165 F with 5W20 vs 190 F with 10W40 or 20W50. No oil Temp gauge but have a Harbor Freight hand held sensor but check surface temp oil filter cover. Have made this measurement many times after the same 6 mile ride in from work. Only run 5W20 in the cooler months.

 

[SZR48207]

Originally Posted By: faltic
My 07 Ninja 250 runs 165 F with 5W20 vs 190 F with 10W40 or 20W50. No oil Temp gauge but have a Harbor Freight hand held sensor but check surface temp oil filter cover. Have made this measurement many times after the same 6 mile ride in from work. Only run 5W20 in the cooler months.


What 5w20 oil are you running in a wet clutch bike?

 

[faltic]

Super Tech, Chevron Supreme, Quaker State

 

[02SE]

Originally Posted By: faltic
My 07 Ninja 250 runs 165 F with 5W20 vs 190 F with 10W40 or 20W50. No oil Temp gauge but have a Harbor Freight hand held sensor but check surface temp oil filter cover. Have made this measurement many times after the same 6 mile ride in from work. Only run 5W20 in the cooler months.


Don't you think that the cooler weather might be the biggest factor in running cooler?

 

[Shannow]

Ive beeb able to get around 15C on my air cooled briggs running at the governor with bookends of 5W20 and 20W60...I can't see a low shear (RPM) environment giving those sorts of temperature differences between the two grades mentioned by the OP.

 

[faltic]

[/quote]

Don't you think that the cooler weather might be the biggest factor in running cooler? [/quote]


Didn't always run 5W20 in the cooler months but have only run 10W40/20W50 in warm weather.

 

[barryh]

Th OP didn't substitute thinner oil except when the oil is cold. Regardless of the weather the 5W40 will be thinner when it's cold, therefore it will take a little longer to warm up than the 15W40. Once the oil is up to temperature there should be little difference unless the HTHS values are wildly different.

 

[alarmguy]

check it again in the summer but yes, a thinner oil like the a 5w40 will generate a tiny bit less heat then a 15w40 but no way that much difference. ( i guess)