Increasing oil weight for hotter climate?

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8
Location
Nevada
Thread starter
Hi all, first post here. Far from an oil expert, and hoping to expand my knowledge a bit.

I ride a late model Kawasaki Z1000 with about 40k on the clock. I've recently moved, and average temps are significantly hotter here. I've exclusively run the bike on Mobil 1 Racing 4t 10W-40 so far, but according to the official owner's manual, it is recommended to use either a 10W-50 or 20W-50 when the atmospheric temp exceeds 104° F (pretty common here).

I've always been the kind of person to simply follow manufacturer recommendations on oil weights, but I've also believed (just a gut feeling, not educated) that I should just find a solid oil and stick with it for as long as I own the vehicle. This is the first time I've had those habits be in conflict with one another.

Does it make sense to switch oils to match the recommendation, or is keeping the same oil a good idea on a middle-aged motor? Additionally, If switching is in fact the best option, would there be any appreciable difference between the 10W or 20W in such a climate? The chart in the manual shows the lowest recommended operating temp of 10W at 14° F, and 20W at 32° F. I don't foresee myself doing any riding below freezing, but would 10W be better for 'cold' starts?
 
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14,733
Location
Upper Midwest
In general the winter rating is irrelevant for warmer climates. It has no direct bearing on the operating viscosity which is what is important for hotter operating conditions. In your conditions there is no difference between using an oil with either winter rating, there won't be a hill of beans difference between the two.

Follow your owner's manual and if the ambient temperature exceeds the indicated temperature then use the 50-grade oil they recommend.
 
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24,196
Location
PNW
Hi all, first post here. Far from an oil expert, and hoping to expand my knowledge a bit.

I ride a late model Kawasaki Z1000 with about 40k on the clock. I've recently moved, and average temps are significantly hotter here. I've exclusively run the bike on Mobil 1 Racing 4t 10W-40 so far, but according to the official owner's manual, it is recommended to use either a 10W-50 or 20W-50 when the atmospheric temp exceeds 104° F (pretty common here).

I've always been the kind of person to simply follow manufacturer recommendations on oil weights, but I've also believed (just a gut feeling, not educated) that I should just find a solid oil and stick with it for as long as I own the vehicle. This is the first time I've had those habits be in conflict with one another.

Does it make sense to switch oils to match the recommendation, or is keeping the same oil a good idea on a middle-aged motor? Additionally, If switching is in fact the best option, would there be any appreciable difference between the 10W or 20W in such a climate? The chart in the manual shows the lowest recommended operating temp of 10W at 14° F, and 20W at 32° F. I don't foresee myself doing any riding below freezing, but would 10W be better for 'cold' starts?
If the manual says 20W-50 is OK down to 32F, and you won't be starting the bike anywhere near that low temperature, then I'd go with the 20W-50.
 
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24,196
Location
PNW
IMO, a liquid cooled street bike has no need for a 20w-50 oil, regardless of ambient temp.
Apparently per the OP, Kawasaki calls out 20W-50 in the manual if the ambient temperature is high enough. Yamaha calls out 20W-50 as a viscosity option on my XSR900 if the ambient temperature is between 50F and 120F. Yamaha also calls out 10W-50 if the ambient temperature is between 10F and 120 F.
 
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638
Location
Colorado, USA
IMO, a liquid cooled street bike has no need for a 20w-50 oil, regardless of ambient temp.
With my Kawasaki ZRX 1200, it's a known issue at hot temperatures with 10w40, oil pressure at idle drops extremely low. 20w50 helps keep a bit more oil pressure at idle. Same thing would apply for the OP in Nevada in the scorching temps during the summer as the temperature needle starts to rise on the engine. IMO, when it gets that hot in any engine whether there is a known situation or not, 20w50 becomes a prudent choice.
 
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8
Location
Nevada
Thread starter
Thanks for the replies, sounds like at the very least 20W-50 shouldn't be detrimental? I'm still hesitant to switch from what I've been having good luck with for years, are there any real downsides to switching away from the oil that the engine has been 'used to'? Or is just me that's used to using that oil?
Apparently per the OP, Kawasaki calls out 20W-50 in the manual if the ambient temperature is high enough. Yamaha calls out 20W-50 as a viscosity option on my XSR900 if the ambient temperature is between 50F and 120F. Yamaha also calls out 10W-50 if the ambient temperature is between 10F and 120 F.
Annotation 2020-07-27 160350.png
Yes, here is a copy of the graph provided in the manual. To me it would suggest I make the switch, as the 10W-40 bar ends sharply at the 104°F mark.

I'm just not familiar enough with the actual properties of engine oils, and can't wrap my head around any potential benefits and drawbacks. My initial thoughts are that the difference should be minimal, and that sticking with 10W-40 is extremely unlikely to grenade my bike; on the other hand, I also like to maintain my bike to the best of my ability, and don't like the idea of running outside spec. Why is a higher weight oil more desirable for hotter climates? Are there problems that could come from running a higher oil weight? I'm finding that more research just leads to more questions.
 
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127
Location
WI
Jury is still out, but maybe a Rotella T6 15w40 would suffice? Or a 10w40/20w50 blend ?
 
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12
Location
Shelton, CT
The 2003 Kawasaki ZG1000 (Concours) I had from 2005 to 2018 did just fine on 20W50 all year round. I never used it below freezing. I did, however, ride it through Nevada when it was hot as balls. I would NOT have run 10W40 there.
My 2008 Kawasaki KLR650 gets to play all year. It gets 20W50 when the leaves are on the trees and 10W40 when they are not.
 
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2,401
Location
Deep in the heart of Jersey
I guess when a mfgr suggests a wt of oil, it's because they tested it at different temps. Harley for instance recommends 10/40 for temps under 40f. For normal everyday riding they recommend 20/50. But they say you can use straight 50 wt when it's over 60f, and straight 60 wt in temps over 80f. I used 20/50 year round and being I keep the bike on a battery tender, it starts without issue when its under 40f. And I don't race it up or drive it for at least 5 minutes to get some heat in the motor . I think a lighter wt oil might help the bike start easier if your battery is old or starting to go. It seems mfgrs think that by putting different wt options in the manual it answers owners question about which wt to use, but it seems to sometime cause more confusion,...
 
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22
Location
Sicily, Italy
Use a good 15w50 or 10w50 and live in peace and your engine will thank you.
Mobil 1 racing 4t 15w50, Redline 15w50, amsoil 10w50, silkolene pro 4 xp 10w50, bardahl xt4s 10w50, motul 7100 10w50 - 15w50.

Greetings from Sicily, here at the moment the temperatures oscillate between 27 ° C in the shade at 9am and after 11am we are around 36-42 ° C
 
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14,733
Location
Upper Midwest
Thanks for the replies, sounds like at the very least 20W-50 shouldn't be detrimental? I'm still hesitant to switch from what I've been having good luck with for years, are there any real downsides to switching away from the oil that the engine has been 'used to'? Or is just me that's used to using that oil?


View attachment 25879
Yes, here is a copy of the graph provided in the manual. To me it would suggest I make the switch, as the 10W-40 bar ends sharply at the 104°F mark.

I'm just not familiar enough with the actual properties of engine oils, and can't wrap my head around any potential benefits and drawbacks. My initial thoughts are that the difference should be minimal, and that sticking with 10W-40 is extremely unlikely to grenade my bike; on the other hand, I also like to maintain my bike to the best of my ability, and don't like the idea of running outside spec. Why is a higher weight oil more desirable for hotter climates? Are there problems that could come from running a higher oil weight? I'm finding that more research just leads to more questions.
Why would you imagine that an oil grade given in the manufacturer's literature be detrimental?

A higher grade gives a higher MOFT. MOFT is king, it keeps metal parts separated. If they don't stay separated then bad things happen. You admit you don't know anything, so do what the manufacturer of the equipment tells you to do. Even if you did know something that's still the proper thing to do.
 
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Messages
182
Location
Caldwell Idaho
Why would 10w when the temps aren't in the 10w range be better for cold starts? That is like the statement my neighbor told me about hay rake types.. He said this type is better because it break off the leaves as much , he heard it on a you tube video,, I said are you not raking alfalfa or clover you are raking grass hay,, grass hay doesn't have leaves .
 
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Messages
638
Location
Colorado, USA
Why would you imagine that an oil grade given in the manufacturer's literature be detrimental?

A higher grade gives a higher MOFT. MOFT is king, it keeps metal parts separated. If they don't stay separated then bad things happen. You admit you don't know anything, so do what the manufacturer of the equipment tells you to do. Even if you did know something that's still the proper thing to do.
^^Good Post^^
To add to that, higher MOFT allows larger sized wear particles to stay within that thicker film, whereas less MOFT would allow the same size wear particles to breach the layer and make contact with the parts the oil is working to keep separated. Someone recently made a great post how even with thicker oil, as oil temp increases, MOFT keeps going down a lot more than what I would have realized. The post may have been by one of the guys posting here, just cannot recall exactly who shared it.

I’ve run 20w50 M1 20W50 V-Twin through the winter here in Colorado and no issues with cold starts on days when the temp gets into the high 40’s/low 50’s when the overnight temp goes into the 20’s and the garage (and thus the bike temp at start up) was much colder than the daytime temps. With that OCI of 5,065 miles in my ZRX1200, shift quality remained smooth and consistent, viscosity stayed right in the middle of 50w range and wear numbers were great.

Since you need not be concerned at all with start up temp at this point, IME, 20W50 is your best choice as any benefit of a 15w50 or 10w50 with respect at start-up temps is moot as has been mentioned already. Not that you are having issues, but the narrower the spread in viscosity, the less shearing you will experience and shift quality will remain better all else equal over an OCI if you run it out more miles.

I see M1 15w50 4T is mentioned. It must be a foreign oil weight offering as it is not available in the USA.
 
Messages
8
Location
Nevada
Thread starter
Again, thank you to everyone who is responding. Receiving some good food for thought! I'm continuing to read other threads on the forum as well; there truly is a wealth of knowledge here.

It seems mfgrs think that by putting different wt options in the manual it answers owners question about which wt to use, but it seems to sometime cause more confusion,...
I can't speak for others, but this has certainly been my experience!

Why would you imagine that an oil grade given in the manufacturer's literature be detrimental?

A higher grade gives a higher MOFT. MOFT is king, it keeps metal parts separated. If they don't stay separated then bad things happen. You admit you don't know anything, so do what the manufacturer of the equipment tells you to do. Even if you did know something that's still the proper thing to do.
I'll try to better explain why I imagine that. In my head, any fluid circulation system would be under more stress when the fluid is more viscous and resistant to said circulation? Certainly this shouldn't be an issue if the manual recommends it, and I'd completely buy that parts like the transmission might even prefer a thicker oil. But at the same time, I can't imagine it's going to be easier for parts like the oil pump to push a thicker oil. Maybe I'm just a worrywart; my fear is that there are parts with preexisting mileage and wear that may see increased stress, or reduced efficacy.

I want to maintain my bike correctly, but when I did some searching I didn't find any evidence of people using a thicker oil than 10W-40 on my specific bike. Only in that blurb from the manual. That's why I'm here, trying to develop my own understanding and make choices that might keep my motor happy for the next 40k.

I already owned up to being far from an expert, and even stated that I'm in a habit of following the manufacturer recommendations, so no need to reiterate that by saying I don't know anything!

Why would 10w when the temps aren't in the 10w range be better for cold starts?
Am I incorrect in my assumption that an oil with a 10W rating would be thinner, and flow easier than one with a 20W rating at basically any temperature under 212° F? Sure, it isn't nearly enough to take full advantage of the lower temp range, but even then, wouldn't it flow through the engine easier on it's way up to operating temp? Am I missing something? You're probably correct that it wouldn't make a difference, but I don't think my statement was completely unfounded.

Not that you are having issues, but the narrower the spread in viscosity, the less shearing you will experience and shift quality will remain better all else equal over an OCI if you run it out more miles.
I feel like this was a helpful tidbit for me! I even did a little reading about viscosity spreads. I also consider the ZRX1200 a close cousin of my bike, so your positive reports on using 20W-50 are meaningful.
Greetings from Sicily, here at the moment the temperatures oscillate between 27 ° C in the shade at 9am and after 11am we are around 36-42 ° C
43° C here at time of writing. Solidarity from Las Vegas!
 
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9
Location
United States
I run the same oil you do in my 2008 ZX14 and my wifes 2011 ZX6R. I live in Texas which is a cooker in summer as you know. 55K on the 14 and 26K on the ZX6 with no problems whatsoever.

My opinion which has no professional basis to back me up is if you maintain your bike with a good quality oil and change it religiously you shouldn’t have any oil related issues.
 
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6,599
Location
Katy, Republic of Texas
Apparently per the OP, Kawasaki calls out 20W-50 in the manual if the ambient temperature is high enough. Yamaha calls out 20W-50 as a viscosity option on my XSR900 if the ambient temperature is between 50F and 120F. Yamaha also calls out 10W-50 if the ambient temperature is between 10F and 120 F.
With my Kawasaki ZRX 1200, it's a known issue at hot temperatures with 10w40, oil pressure at idle drops extremely low. 20w50 helps keep a bit more oil pressure at idle. Same thing would apply for the OP in Nevada in the scorching temps during the summer as the temperature needle starts to rise on the engine. IMO, when it gets that hot in any engine whether there is a known situation or not, 20w50 becomes a prudent choice.
Well, that explains it, seems Kawasaki and Yamaha don't know how to build a motor with a good cooling system. 😲

...

View attachment 25879
Yes, here is a copy of the graph provided in the manual. To me it would suggest I make the switch, as the 10W-40 bar ends sharply at the 104°F mark.
...
Interesting chart.
Most every chart I have seen seems to always show 10w-40 going all the way to the right along with the xw-50 oils.
I do agree the chart seems to show that a xw-50 weight oil is needed.
 
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24,196
Location
PNW
Well, that explains it, seems Kawasaki and Yamaha don't know how to build a motor with a good cooling system. 😲
There are a lot of vehicles with cooling systems and active oil coolers where the manufacturer still recommends thicker oil in hotter ambient climates. The oil doesn't shed all it's heat into the cooling system, so increased ambient conditions must still make the oil run a bit hotter even with active cooling systems employed.
 
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6,599
Location
Katy, Republic of Texas
There are a lot of vehicles with cooling systems and active oil coolers where the manufacturer still recommends thicker oil in hotter ambient climates. The oil doesn't shed all it's heat into the cooling system, so increased ambient conditions must still make the oil run a bit hotter even with active cooling systems employed.
I was joking. Just a jab at Kawasaki and Yamaha (I am a Honda boy).
I know different engine designs have different requirements. But as I said, I do find the chart odd in the cutoff temp for a xw-40 oil.
 
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