SAE 30 in John Deere riding mower

[Quantico]

So do mine, among other choices.

That being said, SAE 30 oil is getting harder to find and not available in synthetic. There are plenty of choices in 10w30 synthetic as well as RT6 in 15w40. B&S also recommends 15w-50 synthetic for commercial use, and that is available in Mobil 1. 15w40 RT6 seems like a good choice to me. When purchased by the gallon it's about the same or even less cost that a conventional SAE 30.

My m18 and m20 kohler horizontal twins cant use a 10 30 oil. They knock and the low pressure oil light stays on. Commercial simplicity tractors are 12 to 18 thousand each. So i am not destroying them for a test ..
Maybe i should stock up more straight 30 ?? Good idea ?

 

[Kjmack]

My m18 and m20 kohler horizontal twins cant use a 10 30 oil. They knock and the low pressure oil light stays on. Commercial simplicity tractors are 12 to 18 thousand each. So i am not destroying them for a test ..
Maybe i should stock up more straight 30 ?? Good idea ?

My zero turn with a Kawasaki runs the smoothest on Valvoline 10w40 synblend out of all the oils I've used , Mobil 15w50 was a no go , ran rough . My manual calls for 5w40 in my conditions .

 

[Quantico]

Is your zero turn over 35 years old ?

 

[Quantico]

The sunstar simplicity tractors were out around 1983 . Mine were 1986 or so. Magnum twin kohlers . 20 hp with tons of torque were quite the thing over 35 years ago

 

[jeepman3071]

Is your zero turn over 35 years old ?

I use the 15w40 in many older engines, including Kohler Magnums. Love the sound of those opposed twins. No oil pressure issues, maybe even a tad bit higher pressure at hot idle with the 15w40.

 

[Quantico]

I now own two sunstars. At one time I had five of them. On several i tried 10 w 30 or 10 w 40 and the oil pressure light said no.
I never tried Mobil 1 15w50... one of my favorites. But at this point I am buying a couple cases of straight 30 just to have them here. That should last a long long time. I forgot how much oil they use. But its not a lot.

 

[bchannell]

It seems every manufacturer recommends something different. B&S is now recommending their 15w50 syn for most things, Kohler is still rec'ing 10w30, Kawasaki on paper recommends 20w50 in some cases, but if you call the tech support, I'm betting they'll say straight 30wt. yatta, yatta, yatta,
I know what works over many years. ALMOST ANYTHING! If you just use some common sense, it'll be a sunshine and roses. 30wt, 10w30 HDEO, 15w40 HDEO, or almost any syn auto oil in the 30 or 40 wt and depending on location and heat, a 50wt and you'll never have to worry about oil being a problem.
Someone else mentioned how robust small engines are, and that is so true. You could run them on 3 in 1 oil and they'd probably last forever. I'm 65 years old and been mowing and working in the farm/yard all my life, many mowers, tractors, tillers, weedeaters, you name it, and I've never had ANY engine fail due to oil, never once.

 

[Revving2Redline]

We bought a Briggs & Stratton Ride lawn mower that took SAE 30 weight, well after the oil siphoning after almost 2 years of not changing the oil I used red line 30 weight. Didn't even take a whole quart. I wonder now if I'll get more blades of grass per revolution with this supreme oil

 

[Quantico]

We bought a Briggs & Stratton Ride lawn mower that took SAE 30 weight, well after the oil siphoning after almost 2 years of not changing the oil I used red line 30 weight. Didn't even take a whole quart. I wonder now if I'll get more blades of grass per revolution with this supreme oil

Oil siphoning after two years of not changing oil ? What are you saying ?? I am confused . And why not change the oil once or twice a year. Its like 6 dollars a year or less

 

[kschachn]

My kohler m18 and m20 engines show dramatic low low oil pressure with anything but straight 30. Not sure if the poster engine is from 86 when my engines were made. But 10 w 30 will cost me 3000 to 4000 dollars per horozontal engine. Thats not what i want..

That’s strange considering what a 10w30 is compared to a straight 30. “Dramatic low low oil pressure” on a 10w30 sounds very odd.

 

[nbpt100]

You are overthinking it. Just use 10w30 and change it per the manual. If you really want to go all out pay up and get full synthetic 10w30 small engine oil. Kenetix, Kawasaki, Kholer or Brigg & Stratton. Plenty of brands out there. Sleep well at night.

 

[jeepman3071]

That’s strange considering what a 10w30 is compared to a straight 30. “Dramatic low low oil pressure” on a 10w30 sounds very odd.

Yep, they should be the same viscosity at operating temperature. In his case my bet is on a bad sensor, it's common on those engines.

 

[The_Eric]

I use the 15w40 in many older engines, including Kohler Magnums. Love the sound of those opposed twins. No oil pressure issues, maybe even a tad bit higher pressure at hot idle with the 15w40.

I've got an M18 in a snapper garden tractor with actual dual exhaust.. Sounds so good, especially when you hit a heavy patch and the govener gives the throttle a tug! I love mowing with it, just put my ear-pro on and zone out listening to it for hours.

 

[vwmaniaman]

I use 30 wt in mine. a VW magazine tested heat dissipation with conventional and synthetic and conventional won. You right though as it is getting harder to find. My little 65 Beetle gets straight 30 wt and purrs. So does all my OPE.

 

[wpod]

15W-40 is the new straight 30 !