The correct engine oil
 

I am going to change the oil in the 129 I got recently...I know it calls for straight SAE 30...any one have a brand they prefer or would recommend?
Thank you....Mark

Well Kohler will tell you their earl is the best-est in all the land.
use Non detergent 30W of your choice, they are all good
Just change it often :beerchug:

As George said, straight 30W non detergent.

I use Shell Rotella SAE30
( Thanks to Roy in the post below for "jogging" my memory of the brand I use)

You want a SAE 30 oil that has a lot of ZDDP which is a zinc phosphor based additive used to reduce wear on high friction parts of older engines. Most car engine SAE30 oil doesn't have ZDDP because the additive destroys catalytic converters. Basically you want a SAE30 oil made for off road/highway use.

A couple of choices are:
Kohler Magnum SAE30 (with approx 1500 parts per million of ZDDP)
Shell Rotella SAE30 (approx 1000 PPM)
John Deere Torq-Gard SAE30
Tractor Supply – CountyLine SAE30 Lawnmower Oil
Tractor Supply – Traveller Heavy Duty SAE30
Case/IH Low Ash Engine Oil 30W (737-3029 Qt, 737-3061 Gal)

ZDDP: Zinc Salt of Dialkyl Dithiophosphoric Acid or Zinc Dialkyl Dithiophosphoric Acid Salt

Well, I'm confused.... A couple of you recommend using non detergent oil though I believe the OP was referring to an older tractor/engine the he just aquired. I thought the non detergent oil was recommended for new or rebuilt Kohler engines during break-in period. And, after break-in period...use
SAE 30 detergent oil SF or SG. Can you non detergent boys elaborate?

From the K301 Kohler owners manual

Back in the 1930's or 1940's ,, I do not know exactly when,, non-detergent was used by farmers.

After using the oil, they had a tank, it looked to be 50 to 100 gallons, that the used oil was put in.

After a while, the oil could be pumped off the top, it looked as clean as new,,
the farmer would then use his "clean" oil,,
that did nothing for non-visible contaminants like acids,,

Tractors did not have air filters then,, and no oil filter, oil got dirty FAST,,
I would bet some of those tractors got daily oil changes,,

Detergent in oil simply keeps dirt in suspension, so that the dirt will come out when you change oil.

Even detergent oil will let the dirt settle out, if the oil sets for years,,,

It is said:
Detergent oil cleans the engine as it splashes around,
and the filter does it's job picking up any particles/dirt that is larger than the micron of the filter.
Oh Wait, no filter,:bigthink:
so one would want the dirt/particles to not stay in suspension and settle in the pan to be drained off with the oil, at change time.
It makes sense, and that is what the engine manufactures say.
Me,
I never was small enough to go inside an engine to see if that is really the case, but have changed some oil that had crud in it.
Actually, if oil is kept clean by frequent changes, I don't see a problem with any of it.

Mark, like Matt points out with his excerpt from the Kohler engine manual, Kohler wants us to use a 30wt oil whenever the temps above freezing. They also want it to be equal or better than a service class SG or SH. This means the oil is a detergent oil. What detergents do is keep stuff in suspension. Just like the detergent you use in your washing machine. It keeps all the poop particles in the wash water, rather than redepositing them on your undies. For oil, this means that when you drain the oil (hot, after running), you flush out all the crud that‘s built up with use (dirt, wear particles, condensation, etc). If you want a non-detergent oil, you will need to look for a service class SA oil. This is the oil class that’s recommended for break-in. But NOT for daily use thereafter.

Interesting read about oil service classifications at this site....

http://www.pqiamerica.com/Labels.htm
and here
http://www.pqiamerica.com/apiserviceclass.htm