Sorry @texases I fixed that first sentence I couldn’t help myself.
TheWonderful90s:
I gave you a sincere opportunity to defend yourself. Instead you replied with only more anecdotal evidence.
I have all I need.
Thank you.
I tried to copy and paste the Brigg’s info that Barky posted, but not sure if it worked. Looks odd on the iPhone as I type this. But, anyway.
Anyone have any idea why 10w30 would possibly cause more oil consumption than 5w30 in a Briggs engine? I found that interesting. It seems almost backwards since 5w30 is going to be a lighter oil, at least some point during the engine’s operation.
Not trying to start or prolong any arguments here on lawnmower talk 
He’s nuts. It’s that simple.
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One more piece of very bad advice, to add to the stack.
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Race cars have been using synthetic multi weight oils for decades, not single weight oils. The last of the Porsche air cooled engines built in the 90s specified multi weight synthetic oils. Both of these examples bust your statement.
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edit: Ignore everything I said below about this. I missed the most important part. The 5W30 oil on that engine is only allowed when temperatures are below 40F! The 5W30 synthetic is allowed at higher temps because it’s synthetic, and synthetics can handle higher temperatures.
The only reason I can think of is that either the manual is mistaken, or it as assumed that the 5W30 oil will be some kind of synthetic blend that can handle higher temperatures whereas the 10W30 is assumed to be a traditional oil that can’t, reason being that it’s based on SAE 10 with viscosity modifiers to make it thicker within a certain temperature range.
5W30 wasn’t even available until the mid 80s, whereas 10W30 came out in the 50s. I assume that 5W30 contains some technology that didn’t exist prior to the 80s, and therefore 10W30 may not have it. Perhaps this technology allows it to perform better at higher temperatures.
That’s because there is no such thing as a single viscosity synthetic oil, when measured using the standard method of comparing it to non synthetic oil. 10W30 is not a viscosity measurement, it’s a claim that the oil will perform like winter compliant SAE 10 in cold temperatures and like SAE 30 in a warmed up engine.
For instance a fully synthetic oil that is designed to behave like SAE 30 in a warmed up engine might end up being something like 7W30 due to synthetics not changing viscosity with temperature as much as non synthetics do. This also means the synthetic will out perform SAE 30 in a hot or overheated engine.
A ‘claim’ that is completely based on viscosity meaurements!
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And THAT is also very wrong. Geez where do you come up with this stuff?
And this
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Greater oil consumption that the oil listed above 10W30; SAE 30
That’s a synthetic blend, and could be something like 40W50 if you tested it. By not advertising the cold weather rating, they can get away with altering the blend without changing the rating.
See my edit with full synthetic from Royal Purple. I can list dozens of full synthetic single weight race oils as well as multi weight. The favorites these days are 0w10s, and 20s for lower friction.
All these companies also sell multi weight race oils.
They might be doing that because customers are used to thinking that multi viscosity oils are not optimal for high performance or racing use. They can also alter their formula or blend and not change the rating this way. If it really is pure synthetic then the cold viscosity shouldn’t be the same as regular SAE 50 (assuming the rating is for warmed up oil). It would be interesting to test this. I’ll have to get some.
Wonder if cars will go the way of my lawnboy mower, no oil change possible, not needed!
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That’s a nice graph. I tried to find one like that once and couldn’t. I don’t know where you got that graph, but it would appear that the 5W40 is a synthetic oil, which is technically not the same thing as a multi weight, even though it’s marketed so that the customer wouldn’t know the difference. If it was an actual multi weight oil I believe the dotted line wouldn’t be straight.
Why not straight?
Because there is a critical temperature where the viscosity modifier molecules unwind making the oil thicker, where the line would go flat. Once they are fully unwound, the line would become more straight again and would then follow along with the 40 weight line.
Is it one of the new Briggs and Stratton where it is designed to burn off oil and you only add new oil? That’s what I was getting at in my other thread about high oil consumption with Mobil 1. I wonder if their Extended Performance 20,000 miles of protection is based on adding a lot of oil during that period.
That is not just wrong, it is INCREDIBLY wrong.
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