Viscosity failure using multi-weight oil in Rhino

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Hi all, new to the forum but not new to oil analysis. The subject vehicle is my 2008 Yamaha Rhino (side x side ATV/UTV).
I have owned this vehicle since new and decided to have an oil analysis done after 3,000 miles/200 hours. For the first test at 202 hours I was running Mobile 1 syn 15w-50. The oil test was done with 45 hours on the oil. The results were a viscosity failure with the cSt 100c test reading 10.3 The lab was so puzzled they ran the viscosity test twice!

Okay, second test, same vehicle with 54 hours on Rotella T-6 syn 05w-40. Viscosity cSt 100c 10.5

We have a problem here, the design of the Rhino engine is eating the multi-weight alive! I am now running straight 40wt at the recommendation of the oil lab. Comments?

--Geoff
 
something is wrong or maybe nothing is wrong. You will have to see if the shearing will hurt engine life. i would be interested to see the rest of the oil report. And you need more info than just a viscosity number to tell if your ride is not functioning properly.
 
What does Yamaha recommend for this engine?
It may be that Yamaha knew that this engine would shear oil, and recommended a grade taking that into account.
I doubt that Yamaha recommends a straight forty grade.
Is there anything about this engine that would make it unable to survive on the thirty grade it sheared the M1 and the T6 to?
What kind of wear metals did you see in your two UOAs?
 
My Rhino engine runs fine, but it sure sounds a lot better with 40wt than it did with the viscosity at 10wt. As far as the other lab results, I showed elevated levels of copper and nickel, but once the lab tech I was talking to realized that the Rhino engine and transmission were using the same oil he said the copper and nickel levels were okay. My piston and bearings were not deteriorating. And I should mention that this engine is a 700 cc water-cooled one clyinder engine with a max rpm of 8500, although I rarely run it at max.

Yamaha sells their "own" (repackaged) oil and sells 15w-50 full syn for $21.00, a blend oil, and the basic 10w-40 dino oil for $6 a quart. I don't buy their stuff, but to answer the question, they do not recommend any straight weight oils.
 
I think the Rhino engine/trans is very similar to the engine in the Grizzly quad. So you have the engine, a wet centrifugal clutch, A simple singe speed multi range transmission, and a transfer case, all running in common juice. I cannot remember if the transfer case has a chain or is gear drive, I'd have to look at my grizzly manual. How was the fuel dilution?
 
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Yes, the Rhino 700 engine is from the fuel-injected Grizzly. The transfer case for Hi-low range and reverse are incorporated into the engine. No elevated fuel, or any high levels of anything else. If my scanner was working I would post the results of the two oil lab tests, but all I can say it is NOT MY engine that is the problem, it is the internal design of the engine that is destroying the multi-weight oil.

I posted my results on the most popular Rhino forum (see link)and I got a couple of people to get their oil tested but have not heard of their results yet. I was looking at this forumm to see if anyone else had the Rhino multi-weight oil failure.

http://www.rhinoforums.net/general-rhino-discussion/58002-rotella-synthetic-rhino-660-a.html

--Geoff
 
Mobil 1 TDT 5W-40 and M1 15W-50 both shear down to a 30wt in my K75C after 4000miles. Even when cut down they give me 65PSI oil pressure at 2000rpm and have protected my engine now for 139,000 miles and 26years.

I wouldn't call an oil cut down to 30wt viscosity "destroyed".
 
Hi,
nolids - Such shearing is to be expected and will have been well anticipated by the engine's Manufacturer. It is always wise to use the lubricant specification recommeded for the application by the Manufacturer
 
Originally Posted By: ammolab

I wouldn't call an oil cut down to 30wt viscosity "destroyed".


I didn't say that, I said my oil was cut down to 10wt oil. Would you run your engine on 10wt oil?
 
Originally Posted By: Doug Hillary
Hi,
nolids - Such shearing is to be expected and will have been well anticipated by the engine's Manufacturer. It is always wise to use the lubricant specification recommeded for the application by the Manufacturer


I don't know if Yamaha is aware of the problem, if they are they are keeping it a secret. I'm one of those persons who has been around long enough to know that Yamaha doesn't make their own oil, they use what is availble in the marketplace and have it bottled with their name on it. I'll be calling my local Yamaha dealer today and see what they say. As far as the oil lab says, the problem would occur no matter which multi-weight I am using. That's why they recommeded a straight weight oil.

--Geoff
 
Originally Posted By: nolids
Originally Posted By: ammolab

I wouldn't call an oil cut down to 30wt viscosity "destroyed".


I didn't say that, I said my oil was cut down to 10wt oil. Would you run your engine on 10wt oil?


Look at the viscosity charts here on the site. Your oil WAS NOT cut to a 10wt. The viscosity result figures you quoted (Viscosity cSt 100c 10.5") are those of a 30wt oil.

http://www.bobistheoilguy.com/viscosity-charts/

Would I run my engine with the viscosity figures from your analysis, an oil cut to a 30wt? YES, I have been doing that in my bike for 26years.
 
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Using the words you have, I can imagine the unrest and anxiety you've caused in all of those who read your take on the analysis results.

There was no viscosity failure and you're not operating at a 10wt viscosity. Oil 101: 100C cSt viscosity != wt of oil. In other words, each has a range, which doesn't have a 50 wt oil at 50 cSt at 100C. This information is readily available here on this site, so before you rowel your quad buddies up any more, do some reading.
 
Originally Posted By: ammolab
Look at my K75C oil cSt @ 100C: 9.48, 10.95, and a wopper 13.71.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2463396&page=1

All "normal" shear effect after mileage in this engine. NO viscosity failure at all.


I looked at your lab paper. You are saying you are running 20w-50 oil and you think viscosities of "9.48, 10.95, and a wopper 13.71" is normal? That is low, low and low viscosities. You need to start running straight 40wt or even straight 50wt oil.

--Geoff
 
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Originally Posted By: ammolab
Originally Posted By: nolids
Originally Posted By: ammolab

I wouldn't call an oil cut down to 30wt viscosity "destroyed".


I didn't say that, I said my oil was cut down to 10wt oil. Would you run your engine on 10wt oil?


Look at the viscosity charts here on the site. Your oil WAS NOT cut to a 10wt. The viscosity result figures you quoted (Viscosity cSt 100c 10.5") are those of a 30wt oil.

http://www.bobistheoilguy.com/viscosity-charts/

Would I run my engine with the viscosity figures from your analysis, an oil cut to a 30wt? YES, I have been doing that in my bike for 26years.


This.

It is perfectly normal for oil to drop a grade in some of these applications. The key is to see if wear is adversely affected, etc.
 
Originally Posted By: nolids
Originally Posted By: ammolab
Look at my K75C oil cSt @ 100C: 9.48, 10.95, and a wopper 13.71.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2463396&page=1

All "normal" shear effect after mileage in this engine. NO viscosity failure at all.


I looked at your lab paper. You are saying you are running 20w-50 oil and you think viscosities of "9.48, 10.95, and a wopper 13.71" is normal? That is low, low and low viscosities. You need to start running straight 40wt or even straight 50wt oil.

--Geoff


Low yes, but that oil is 30wt viscosity still. Those numbers are TEST RESULTS, not, repeat NOT API viscosity numbers. Where did you get your "10wt" oil fear from?
 
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Thanks for the information-- that is why I am here! I was reading it wrong and not using a conversion chart. But I talked to my oil lab technician and he told me I should be reading 12.5 to 16.3 viscosity @ cSt 100c. And with my low milage and hours on the oil (500 miles and 50 hours) the engine was definitely destroying the viscosity and would of been down to 10wt sae in short order.

--Geoff



Originally Posted By: ammolab
Originally Posted By: nolids
Originally Posted By: ammolab

I wouldn't call an oil cut down to 30wt viscosity "destroyed".


I didn't say that, I said my oil was cut down to 10wt oil. Would you run your engine on 10wt oil?


Look at the viscosity charts here on the site. Your oil WAS NOT cut to a 10wt. The viscosity result figures you quoted (Viscosity cSt 100c 10.5") are those of a 30wt oil.

http://www.bobistheoilguy.com/viscosity-charts/

Would I run my engine with the viscosity figures from your analysis, an oil cut to a 30wt? YES, I have been doing that in my bike for 26years.
 
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