T5 over the winter ?

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Dec 22, 2011
Upstate NY
I got a deal on Rotella T5 last week, and was planning to use it in a couple pieces of OPE that need that grade (10W30). My garden tractor is coming up on a change as well, and thought I might use that in it too. It has a Kohler CV20, but I also plow snow with it thru the winter. (I'm in upstate NY).

I usually run a full synthetic 10W30 in the tractor all year (like M1 or PP), am I going to notice that the T5 is more viscous during cold starts, or will it be pretty much the same ?
You can look up the cold viscosity specs. T5 10W30 is pretty close to T6 5W40 for cold viscosity, so I think its reasonable.
I try not to start the tractor when its really cold, and usually it doesn't snow much then anyways. At 20F any of them are fine, at -20F then it starts to matter a lot.
I lived in Oswego, NY (on Lake Ontario) years ago and I had to use 5W-30 or 0W-30 to get decent cold starting at -10 which was all too common. It isn't an issue if the machines are stored in a heated garage or shed though.
Your owner's manual recommends 10w-30 from 0 degrees -> up.

It recommends 5w-30 from 32 degrees
It appears that you should be using 5w-30, especially if you're storing it in an unheated building, and will be firing it up cold.
To expand on my earlier comment... the opportunity to edit has passed...

I switched from Pennzoil Platinum 5w-30 to Pennzoil Semi-Synthetic 5w-30 in the middle of the winter last year... and last year was a bad one.

There was not a huge difference, and the numbers on both oils are similar.
FWIW - I've run Rotella 15w-40 winters without any noticible difference in starting performance between that and T6. This is on a briggs opposed twin with a poorly designed starting system to begin with.

My tractor is stored in my garage, which does not typically go below freezing but isn't heated either. If I were storing it in an unheated outbuilding, I'd be more inclined to go the T6 route.
Thanks everyone, I think I'm going to try and find some space in the garage to keep the garden tractor a little warmer. She doesn't see enough hours to justify doing 2 oil changes for less than 10 hours of winter service.
x2 on storing it in a heated garage. If you need the tractor, it safe insurance.

The Kubota 4330 started just find at our -25*F temps last winter. It was stored in a heated garage. I don't even think she noticed the cold.
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