Magnum 18 - oil weights for cold weather

[wildbill59]

So, my next question concerning my new-to-me Deutz Allis with an M18S. It's set up with a plow, I'll be using it in cold weather. My manual says to only use SAE 30 over 32 degrees F, and is says do NOT (yep, in capital letters) use 10w30. But then, under the little graph with the degrees and arrows, it says that 5w20 or 5w30 synthetic can be used up to 40 degrees. I'm fine with using synthetic, and I like the idea of up to 40. There are days when you're plowing way below freezing, but also still plowing on days when it's warmed up and above 32 degrees. But it just seems strange to me - to go from straight 30w to 5w20 - wouldn't it make sense to go from 30 to 10w30 synth? I'm new to using these Magnum engines in the winter - I've used Commands before, and with their hydraulic lifters, it was pretty easy - 10w30 synth, summer and winter. I love my Kohler manuals, but I've found some pretty glaring misprints (or just plain old mistakes) concerning things like spark plug gap, gasket application, and torque specs. So I normally listen to manuals, but I'm a little nervous about going from SAE 30 to 5w30, especially in an engine with solid lifters and 500 hours on it. What do you all think? I'd love to hear some opinions, thanks in advance!

 

[BlazNT]

I have been running 5w30 conventional oil for 2 years in my 1994 craftsman lawn mower/snow pusher for 2 years. I only use it in the winter. It works just fine.

This is from my manual for the Magnum engine I have.
*Use of synthetic oil having 5W-20 or 5W-30 rating is acceptable, up to 4C (40F). **Synthetic oils will provide better starting in extreme cold below -23C (-10F).


Straight 30-weight (Kohler "Magnum") oil is preferred. SAE 10W-30 oil is not recommended above 32F. Using this oil substantially increases oil consumption and combustion chamber deposits.

 

[reynoldston]

My engine is a Magnum 12 in which I run a full synthetic 0W-40 Amsoil. Seeing I am running a snowblower on a garden tractor in -0 temperatures the engine is running under full power. The engine has over 1000 hrs. and still running strong. Its also used in the summer time to mow grass as a loaner for my shop with the same oil. Seeing its a loaner I have a feeling its used hard. I do keep a eye on the oil level because it does use some oil through the seasons.

 

[wildbill59]

Thanks for the answers, guys. Think I'll go with a 5w30 synth. Been looking for Amsoil, but hard to find in my area. I've heard lots of good things about, need to give it a try sometime. Thanks again!