B&S Lawn mower oil type recommendations

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sajohnson

sajohnson

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I just found this B&S page

https://www.briggsandstratton.com/n...wer-oil-type-and-capacity.html#oilfinder

Something on the oil viscosity chart does not make sense. It indicates that 30W; 10W-30; and 5W-30 *synthetic* are good to 100*F -- but it shows 5W-30 dino oil topping out at 40*F.

Looks like a mistake to me, any thoughts?

Something interesting is that B&S recommends synthetic oil. I agree, I use it exclusively in all of our vehicles and equipment, but I don't think I've ever seen a mfr say much at all about synthetic vs dino oil, let alone give it such a strong endorsement.



B&S lawnmower oil recommendations Capture.PNG
 
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Looks like 5W-30 is snowblower oil. With the description to the left of the chart it's hard to see how it's a mistake.
 
Their oil recommendations never made sense to me. Why would a 10W30 oil result in more oil consumption than a 5w30, regardless of conventional or synthetic? In my climate, a synthetic 30w/10w30 or a HDEO 10W30 is my choice. If I was down south and/or doing commercial work, a heavier oil might be considered.
 
I think that chart is a misprint. I am looking at the B&S manual that came with my new Toro Recycler. Synthetic 5w-30 covers the full temperature range on the chart.
 
Originally Posted by jorton
I think that chart is a misprint. I am looking at the B&S manual that came with my new Toro Recycler. Synthetic 5w-30 covers the full temperature range on the chart.


Thanks jorton. The reason I ended up at that page is because I couldn't find the manual for our Toro Recycler.

On the chart above, synthetic 5W-30 covers the full range from 100*F down to something below -20*F, but for some reason the chart shows regular 5W-30 only being good to 40* max. Seems odd.
 
It's not a mistake. The idea behind the chart goes like this:

5w-30 only goes to 40* based on this assumption: use of conventional oil with a wide viscosity spread is more prone to breakdown at high temps (VII shearing?) seen in air cooled engines than a synthetic 5w-30 (more robust) and 10w-30 (not as wide spread.) This is why the 5w-30 only goes to 40 degrees-- at cooler temperatures it's less prone to degradation. 5w-30 synthetic goes higher, because well, it's synthetic!

10w-30 above 80 degrees can cause increased consumption: according to the chart, the only other oils appropriate for that temperature is SAE 30, synthetic 5w-30, and 15w-50 synthetic. Again this is B&S assuming the worst in oils, but out of all those options for > 80 degree use, the conventional 10w-30 multigrade is more likely to break down or shear out of grade, etc. Of course it is, because SAE30 is a mono-grade, and the other two are synthetic (supposed to be better... again, crude generalizations).

Remember, Briggs does not know what oil you're buying. They have to make assumptions based on regular Joes who know nothing about oils, buying the cheapest thing available on a store shelf. Obviously you can take their viscosity recommendations with a grain of salt when you're buying top-tier conventionals. But I think their chart is pretty logical when you consider it's aimed at people who have zero understanding of what anything on an oil bottle means and are likely to buy the cheapest no-name junk oil they can get their hands on.
 
I've never seen a chart that shows 5W-30 is only good for up to 40*F -- regular or synthetic.

In fact, I don't recall seeing a chart that differentiates between regular and synthetic. Any charts I've seen over the decades have not made any distinction. They refer to conventional/dino oil. If a person wants to use synthetic that's OK, but there is no separate chart that indicates synthetic has a higher temp range.

Usually the high temp limit for, say, 5W-40; 10W-40; and 15W-40 is the same.

Even if there are unique concerns with small air-cooled engines, it's hard to believe that 10W-30 is good to 100*F, but 5W-30 only up to 40*(?!).

Regarding 'cheap oil' -- my understanding is that as long as an oil meets or exceeds a given API service rating (SJ/SM, etc) it's acceptable to the mfr. As far as I know, all 'no-name' oil is made by one of the big oil companies. That stands to reason. The auto parts stores do not have their own refineries. I buy name-brand synthetic, but any oil with the mfr spec'd API rating and viscosity should be fine as far as the equipment mfr is concerned. IOW, for the engineer coming up with the 'recommended oil' chart, there should be a minimal difference between say Pep Boys house brand oil and a name brand oil of the same rating(s) and viscosity.

Engine mfrs do not void a warranty because the owner used Walmart oil (for example) -- as long as it meets their published specs.

Many small engine mfrs now allow the use of multi-grade oils and synthetic oil. Some warn of increased oil consumption with 5W-30 or 10W-30, but I've never seen it.

I've been changing the oil in everything we own that has an engine. One of those pieces of equipment is a Honda mower. The chart in the manual says 30W / 5W-30 / or 10W-30 are all good up to exactly the same temp -- it appears to be about 110*F.
 
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Originally Posted by ammolab
My 1998 Cherokee list 5W-30 only to 60 degrees F...10W-30 good beyond 100 degrees.

You're comparing apples and oranges.
 
That Briggs chart is exactly correct. Exactly. It has been fine tuned over years and years of real world experience with small engines. It's not a mistake or a misprint.

They just added the 50 weight recommendation about 2 years ago after losing a bunch of engines down south. 30 weight is marginal for an air cooled engine, ran in the south.

I do find it odd that they skipped over SAE40 and 15W40.

Use conventional 5W30 down here on a 96 degree, 100% humidity day and the oil will literally disappear off the dipstick. Mow for 3 hours and your oil will flat out disappear. From full to no oil on the dipstick in a matter of hours.

Use 5W30 synthetic in the same scenario and the oil stays right at the top of the dipstick, practically all season long. Can't explain it, don't know why. Conventional and synthetic 5W30 DO NOT act the same in small air cooled engines.

So the conventional 5W30 use only under 40F makes sense, and is an entirely appropriate recommendation based on observable trends.

Also, Briggs has to account for the average moron. Most folks don't check their oil, don't change their oil, etc. How many engine warranties have they had because joe moron uses conventional 5W30 in south Texas and blows his engine up due to lack of oil?

Sure, every bitoger knows a conventional 5W30 will provide adequate protection over a wide range of temps, IF THE OIL IS KEPT FULL AND REPLENISHED AS IT IS BURNED OFF.
 
I usually run M1 15W-50 in all my OPE, but I got some Delo 10W-30 for $0.75/qt so I'm running that this season.

Seems to run ok but there is a hint of visible smoke when I bring the throttle up to mow. I'll go back to M1 next year.
 
Your just looking at the chart . Read the fine print..... it says. "Different oil types can work best at certain temperatures"
 
Originally Posted by sajohnson
Regarding 'cheap oil' -- my understanding is that as long as an oil meets or exceeds a given API service rating (SJ/SM, etc) it's acceptable to the mfr. As far as I know, all 'no-name' oil is made by one of the big oil companies. That stands to reason. The auto parts stores do not have their own refineries. I buy name-brand synthetic, but any oil with the mfr spec'd API rating and viscosity should be fine as far as the equipment mfr is concerned. IOW, for the engineer coming up with the 'recommended oil' chart, there should be a minimal difference between say Pep Boys house brand oil and a name brand oil of the same rating(s) and viscosity.


Your average consumer does not go to Pep Boys and pick a modern automobile oil off the shelf. They go to their nearest big box store or farm & fleet store and buy the cheapest container of oil that reads lawnmower or small engine in the flavor their owners manual recommends (most often SAE30 but sometimes 10w-30.) Have you spent much time in the small engine aisle of any of these stores? Most oils intended for small engines have no API starburst at all. If you're lucky, there will be an API SJ designation (most often in text, not on the starburst) but I'm pretty confident the majority are not blended by the "big guys" and are probably of dubious quality.

All this assumes they even buy oil at all, which I'm guessing the lion's share don't. Those that do will probably change the oil and consider the mower good for the next umpteen years.
 
M1 10-30 has worked well in my B&S riding mower and pressure washer. No sign of wear or oil consumption.
 
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