I have three bottles of Pennzoil YB 10W-40 left over from my grandfather. I am using Valvoline Maxlife Syn Blend in my car now, so I have no use for it. Would it be ok/smart to use it in a Briggs 675 flathead? Would it be even better than the cheap Craftsman SAE 30 I've been putting in it? I'm thinking it can't possibly be bad for it.
Pennzoil 10W-40 in lawnmower?
- Thread starter Nick R
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Should be fine. Those will run forever on ND30.
JHZR2
Staff member
Should be ok, but 10w-40s may shear a lot, especially in such an application. Probably ok for one oci.
That Briggs will do perfectly fine on the 10w40.
Joel
Joel
What's this about shearing? It's not the first time I've heard about 10W-40s and shearing, and I'm curious/concerned. Why would a briggs shear more than a car would?
Originally Posted By: rudolphna
What's this about shearing? It's not the first time I've heard about 10W-40s and shearing, and I'm curious/concerned. Why would a briggs shear more than a car would?
To achieve such high viscosity spread, a mineral 10w-40 oil has quite a bit of viscosity index improvers in it. When subject to high heat/typical engine operating conditions, this causes an oil to shear.
Due to their primitive cooling systems and often lack of filtration, lawnmower engines such as yours are thought to be particularly hard on oil.
FYI, I run Pennzoil HD30 in mine.
What's this about shearing? It's not the first time I've heard about 10W-40s and shearing, and I'm curious/concerned. Why would a briggs shear more than a car would?
To achieve such high viscosity spread, a mineral 10w-40 oil has quite a bit of viscosity index improvers in it. When subject to high heat/typical engine operating conditions, this causes an oil to shear.
Due to their primitive cooling systems and often lack of filtration, lawnmower engines such as yours are thought to be particularly hard on oil.
FYI, I run Pennzoil HD30 in mine.
Oh I think I see. So it should be perfectly fine to run the 10W-40 for a whole season then (With our yard, thats ~40 hours)
Originally Posted By: rudolphna
Oh I think I see. So it should be perfectly fine to run the 10W-40 for a whole season then (With our yard, thats ~40 hours)
Just keep an eye on the oil consumption...
Oh I think I see. So it should be perfectly fine to run the 10W-40 for a whole season then (With our yard, thats ~40 hours)
Just keep an eye on the oil consumption...
Rudolphna, you'll be fine running the 10W-40. That stuff doesn't necessarily shear down any faster than a 5W-30 or 20W-50.
10W-40 got a bad rap years ago when multi-vis oils were new and the polymers they used at the time were a real mess ... would sludge up a car in no time.
Even a 10W-40 that shears down a full grade will be (essentially) a 10W-30 ... and will perform OK.
Basically, OPE shears the oil thermally ... and because most carburetors are far from perfectly tuned, the oil is thinned out from unburnt fuel.
10W-40 is not ideal ... but it will be fine. Just change it at least once per season.
10W-40 got a bad rap years ago when multi-vis oils were new and the polymers they used at the time were a real mess ... would sludge up a car in no time.
Even a 10W-40 that shears down a full grade will be (essentially) a 10W-30 ... and will perform OK.
Basically, OPE shears the oil thermally ... and because most carburetors are far from perfectly tuned, the oil is thinned out from unburnt fuel.
10W-40 is not ideal ... but it will be fine. Just change it at least once per season.
Ok... So basically, I can expect higher than normal oil consumption, fouled spark plug, and I will have to change the oil more often than usual. Is that right? I really poorly understand this whole viscosity thing. I'm gonna go read that article on the front page again. Where on that chart would 10W-40 fall, generally?
Originally Posted By: rudolphna
Ok... So basically, I can expect higher than normal oil consumption, fouled spark plug, and I will have to change the oil more often than usual. Is that right? I really poorly understand this whole viscosity thing. I'm gonna go read that article on the front page again. Where on that chart would 10W-40 fall, generally?
Are you looking at the viscosity at 40 C comparing a 10w-30 and SAE 30w. Where would the 10w-40 fall under? Will there be more oil consumption>?
Ok... So basically, I can expect higher than normal oil consumption, fouled spark plug, and I will have to change the oil more often than usual. Is that right? I really poorly understand this whole viscosity thing. I'm gonna go read that article on the front page again. Where on that chart would 10W-40 fall, generally?
Are you looking at the viscosity at 40 C comparing a 10w-30 and SAE 30w. Where would the 10w-40 fall under? Will there be more oil consumption>?
Back in the days of GP I oils, early wide spread multi viscosity oils, early viscosity index improvers, there was a problem. Things have changed.
Your little engine would be no more or less prone to mechanical shear than an auto engine. Its oil capacity, compared to an auto sump capacity, and compared to the extra mechanics of an auto engine, would be proportionally close.
Check out the oil temperature threads in this forum. The oil in your engine probably doesn't get as hot as you might think. However, your engine will have hot spots, where air doesn't flow and oil doesn't circulate that well(splash system) This is where the recommended full synthetic really shines.
We now have conventional oils that are GP II/II+ hydro-cracked base oils. They have a higher natural viscosity index than previous base oils. They need less VII to achieve the same spread. The viscosity index improvers are also much improved. They don't shear as badly. They still shear, just not as excessively/quickly.
Pennzoil 10W-40 is reported to be a GP II+ base oil. I don't remember what the high temperature high shear number is, but I think it is near 4.0, which is good. It is also probably higher than the straight 30, mono grade oils that are often used in small air cooled engines. Even an oil with no VII will shear on the molecular level. It has to do with the molecules and their bonding/elasticity. Nothing to try to remember or be concerned about but even an oil with no VII is not immune to shear.
I use 10W-40, full synthetic oils, in my air cooled turf tractor,(14 HP) air cooled lawn tractor,(20 HP) and air cooled trim mowers, (5HP and 3.5 HP). The oldest is 19 years old and still used every week.
Someone said the Pennzoil YB 10W-40 would not be the best choice. I fully agree, not the BEST choice. It is, however, a fully workable, fully usable choice.
I would NEVER take even a full synthetic, GP IV motorcycle oil to 40 hours, but that is just me.
Your little engine would be no more or less prone to mechanical shear than an auto engine. Its oil capacity, compared to an auto sump capacity, and compared to the extra mechanics of an auto engine, would be proportionally close.
Check out the oil temperature threads in this forum. The oil in your engine probably doesn't get as hot as you might think. However, your engine will have hot spots, where air doesn't flow and oil doesn't circulate that well(splash system) This is where the recommended full synthetic really shines.
We now have conventional oils that are GP II/II+ hydro-cracked base oils. They have a higher natural viscosity index than previous base oils. They need less VII to achieve the same spread. The viscosity index improvers are also much improved. They don't shear as badly. They still shear, just not as excessively/quickly.
Pennzoil 10W-40 is reported to be a GP II+ base oil. I don't remember what the high temperature high shear number is, but I think it is near 4.0, which is good. It is also probably higher than the straight 30, mono grade oils that are often used in small air cooled engines. Even an oil with no VII will shear on the molecular level. It has to do with the molecules and their bonding/elasticity. Nothing to try to remember or be concerned about but even an oil with no VII is not immune to shear.
I use 10W-40, full synthetic oils, in my air cooled turf tractor,(14 HP) air cooled lawn tractor,(20 HP) and air cooled trim mowers, (5HP and 3.5 HP). The oldest is 19 years old and still used every week.
Someone said the Pennzoil YB 10W-40 would not be the best choice. I fully agree, not the BEST choice. It is, however, a fully workable, fully usable choice.
I would NEVER take even a full synthetic, GP IV motorcycle oil to 40 hours, but that is just me.
"OK ... So basically, I can expect higher than normal oil consumption, fouled spark plug, and I will have to change the oil more often than usual. Is that right?"
Oil consumption is probably not going to be a problem, spark plugs won't foul any faster and your oil interval shouldn't change either.
"Where on that chart would 10W-40 fall, generally?"
See where 10W-30 falls? With 10W-40 you could extend the top range about 10 degrees or a little more. That's about it.
FrankN4 is correct ... and well spoken. The base oil in Pennzoil is pretty good stuff and the add-pack is at least decent if not really good ... so it will be fine. The warnings you see in manuals about 10W-40 specifically are about 2 decades out of date. They are not inheritantly worse than other multi-vis oils ... as the warnings would have you believe.
I'd use the 10W-40 and change seasonally. Even if you were using a 100% PAO synthetic, I wouldn't go much longer since the mower does not have an oil filter.
Oil consumption is probably not going to be a problem, spark plugs won't foul any faster and your oil interval shouldn't change either.
"Where on that chart would 10W-40 fall, generally?"
See where 10W-30 falls? With 10W-40 you could extend the top range about 10 degrees or a little more. That's about it.
FrankN4 is correct ... and well spoken. The base oil in Pennzoil is pretty good stuff and the add-pack is at least decent if not really good ... so it will be fine. The warnings you see in manuals about 10W-40 specifically are about 2 decades out of date. They are not inheritantly worse than other multi-vis oils ... as the warnings would have you believe.
I'd use the 10W-40 and change seasonally. Even if you were using a 100% PAO synthetic, I wouldn't go much longer since the mower does not have an oil filter.
Well then, I'm gonna get home and do a change. I am want to get anything the new oil picked up out. Thank you all for the very detailed responses.
I'd use it as top-off oil in your Cavalier. You had said that engine burned a fair bit of oil, so this would be an 'economical' solution for top-offs.
It will also work perfectly well in a lawn tractor...Frank and Bror have it right - modern 10W-40's in general are very high-quality oils. It's not going to cause a problem in any application you use it in.....
It will also work perfectly well in a lawn tractor...Frank and Bror have it right - modern 10W-40's in general are very high-quality oils. It's not going to cause a problem in any application you use it in.....
It's strange, since the switch to the maxlife, 500 miles ago, it hasn't burned any oil at all! I just checked it yesterday after changing the ATF, and it hasn't budged at all. Valvoline maxlife has my full endorsement and recommendation. It's great stuff!
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Put it in today. Seems to like it pretty good. The oil that came out was nasty. Gray, looked like it had little particles in it... Gross stuff.
Kestas
Staff member
Why does Tecumseh specifically advise against using 10W-40?
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