Question for oil/lubrication experts

I have a compact utility tractor with 700 hours on it. I don't use it extensively summer or winter. Q:: Which is the better oil to use year-around---30 Wt., or 15-40 Wt?? And WHY??

The best oil to use would be what is recommended in the manual and depends on where you live. The recommendation for Alaska will be different to Arizona. Personally I prefer the multi-weight oil for better starting and hot operation performance. If you didn't live somewhere that got really warm I'd think about using 10w-30. Is it diesel or gas? Sam

Use what is recommended in the owners manual.

There IS no one answer.

If you never use your tractor when it's too cold, or too hot for the oil, much depends on the anti-wear additive package and little else.

If you want the best metal-wear protection, buy a racing, or off-road diesel oil and not oil made for highway use vehicles. That because many anti-wear ingredients were lowered in 2009 for highway oils.

Also depends if petro-based, or non-petro-based.

The oils that can sustain the highest temps - are sythetic single or multi-grades, and some petro-based single grades.

The oils that work best in extreme cold are multi-visc sythetics.

The other issue is the use of polymers to make multi-visc oils from petroleum. They can cause deposits on piston rings, whereas sythetic multi oils do not (generally speaking).

Now, if you never want to think about temps and your oil, and IF you might have to use your tractor at 30 below zero F, or 110 F above . . . buy a sythetic off-road diesel oil like 0W-50, 5W-40 or OW-40 and you'll never have to think about it again. Deere, Delo, Shell, and many other places sell it.

For example, Deere Plus 50 synthetic-base oil.
It's a 0W-40 rated oil. Has more anti-wear additives then highway EPA rated oil.
Has a working temperature range from 40 below zero F, up to 122 degrees F.

Petro-based single-grade 30W oil is fine, but can damage your engine if you start it below 20 degrees F.

Forgot to say that it is a diesel engine.

You guys bring up all kinds of factors that I didn't think of, but should have included in my first question.
I live in SE Nebraska.
The question was in regard to 30W or 15-40Wt Rotella T diesel oils.

I appreciate all your responses.

Do the oil containers state what base the oil is made from?

We have a 2001 JD 4600 that we use JD 5W-30 in, as recommended by the owners manual. This tractor is only used about 50 hrs a year so I don't change it more than once a year. The book says 5W-30 is good up to 85F, when it gets warmer than that I put it away and go fishing. If I needed to use it a lot in warmer weather I would probably switch to 15W-40 but we keep it in Northern MN and I want to be able to plug it in and use it for snow plowing in a couple of hours. This has a Yanmar engine that runs quite cool, 150F regardless of conditions.

If this is a more modern jap compact you should consult your owners manual. Many of them spec the use of a diesel rated 10W30 for most conditions. 15W40 is considered too heavy. Otherwise for an older engine I'd use 15W40.

Rod

Really your call. Very best might be a real, full synthetic diesel rated multi-vis. Any good 15W40 diesel rated will do. Some additive packages in the oils are better than others. I would stay away from any "synthetic blend" as there are no real rules for calling it that - it might be 80 or 90 percent cheap oil and 10 or 20 percent cheap synthetic. My favorites are listed:
1. Mobil One 5W40 diesel full syn
2. Mobil Delvac 1300 15W40 diesel oil
3. Shell Rotella 15W40 diesel oil
4. Chevron Delo 15W40 diesel oil
Tom

What kind of tractor is it and where are you located? Of the 2 oils you list the 15-40 would be better cause it would make for easier starting in the cold and is the most common diesel oil. 10-30 or 5-30 diesel oil would be even better if it gets real cold. Older 2 stroke Detroit diesels are about the only ones that call for single grade oil. What does your manual recommend? I run 15-40 in the Kubota in my skid steer. The manual says 10-30 but that's mostly so they can say one oil works for everything, engine, hydraulics and chain case. I've never had a problem running the 15-40. I have to plug it in in the cold anyway. Dave

It not just the two-stroke-cycle Detroits. Many diesels mention a single grade 30W oil as the best choice when temps allow. Even my Chevy diesel trucks. Just back in the 80s, most tractor companies listed straight 30W as the preferred oil when temperatures allowed.

Deere Co. told us not to use any multi-visc oil in diesel tractors in the 80s. Only 30W or 10W. That until the TorqGuard Supreme 15W-40 came out.

Even my little Chevy diesel Chevette states in the manual - when used in temps 32 F or warmer, single-grade 30W is the preferred oil. It also states that for any continuous sustained driving -SAE 30W is preferred over any multi-visc oil. Manuals for my trucks say the same.

Detroit two-stroke-cycle diesels are one of the few, however, that have never recommended any mutligrade.