Another Synthetic Oil Question

[DWCox]

I recently bought an 05 JD 790 and I build up the hours on it rather rapidly in bursts (projects during breaks). Anyway, about a month and a half ago I did the 50 hour service, and just put the standard JD dino oil recommended at the JD dealer. I am now over 100 hours and will likely be at 150 within the next two weeks.

I was chatting with the JD guy at the parts counter this week and he raised an interesting point. Since I change my engine oil and filter every 100 hours (which he does on his tractors as well), he suggested there is no benefit to going with synthetic oil. Since I use synthetic in all our vehicles, I had planned on switching to synthetic on the next change, but his point gives me pause. In other words, why spend the extra $ on synthetic if there are no advantages beyond extended oil changes (and I cannot bring myself not to change it at 100 hours, since I work that little engine very hard). Consequently, my question is, are there inherent objective qualities to synthetic oil--beyond extended life--that warrant using it in a small diesel engine for such a short duration?

Oil is not my specialty, so any helpful thoughts on this are greatly appreciated.

 

[RWEST]

Except for the 310D, which gets 250 hour OCI's, I run 100 hour OCI's in all the diesel stuff, so I'm in the same boat. The primary reason for using synthetic (RTS 5-40 in some, J-D 0W-40 in others) is for ease of cold-weather startup. The difference is definitely noticeable, at least it was to me (or maybe it was the placebo effect? ), and my brothers when they switched their J-D's.

In addition, the lighter oil's improved cold-flow characteristics probably helps it circulate throughout the engine more quickly than the common dino 15-40. My opinion.

 

[WH401]

I'd say the biggest advantage would be the cold weather starting. Tractor's spend more time idling or at a lower rpm and not getting fully warmed, compared to that of a car so extended intervals may not be a warranted thing. Depends on the type of work you do with your tractor, as you state that you work it regularly.

Your about in the same general climate as me, maybe a little colder though. I plan to change to Amsoil when I get to 100 hrs. Yes the synthetic is more expensive, but even if you aren't going for extended intervals, the benefits are proven.

 

[RalphVa]

Advantages:

1. Lower viscosity to improve cold weather starting.

2. Lower viscosity to improve fuel economy while cold. The newest Mobil 1 0w30 claims to have fuel economy credits over and above normal synthetic, too. It's not heavy diesel rated but is diesel rated and is certainly good for 100 hours. It's what I use and change once/year or at 100 hours.

3. More hp. This is why the race car drivers use it.

Ralph

 

[sixdogs]

Most engine wear occurs at start-up and synthetic protects protect better than dino oil at that instant. It's thinner-flow characteristics in colder weather also helps and the ability to handle combustion byproducts would benefit a tractor with lesser use. Like ours.

Most of us start our machinery way more than average and cold-start wear can be an issue. That's why I now use synthetic in everything I can.
And further, JD 0W40 syn is one of the best and lowest priced products out there with sufficient quanities of the "zinc" or "phosphorus" anti-wear additives that have been reduced in the newest-rated oils. Search this site for more on that topic.

I use JD 0W40 syn in my 790. Note here, some earlier 5 gal. pails if JD 0W40 was labeled as "partially syn.." when it is full syn... Had to call the engineers at JD to figure that one out. Mobil One for turbo diesel is also a good one.
Just my personal opinion. Good luck.

By the way, your "Pond Blog" photos are unbelievable in the work that was done and the role the JD790 played. Congrats on a well-done job and excellent photo recording of the events.

 

[Surge]

Just to add to oil selection confusion, you have other options to obtain better flow and viscosity benefits as well. You could try a 10W30 rated diesel oil such as Rotella T or standard Mystic or even sythetic blends such as Rotella SB or Mystic JT-8 Synthetic Blend. They are slightly higher than a standard 15W40 but carry most of the standard ratings and applicability to a broad range of tractors and engines. You may want to consult your manual on the use of different grade oils. I cannot recall if there are any 15w40 synthetic blends. I use a 15W40 standard oil in the summer, usually Rotella or Mystic when it can get to 100+ and then switch to the 10W30 in the winter as my tractor is in an unheated second garage. It was 4 degrees yesterday (it had been 4 below the day before so the oil was cold) when I went out to plow snow and I cranked it over the second try without have to use the glow plug. You can obtain these at almost half the cost of the Rotella 5W40 full synthetic.. however, were only talking a difference of about $10.00 or less, so not a really big deal either way dependent upon your usage. I did try the Rotella T 5w40 a couple of times a few years ago but that was back when you could get it a Walmart for about $12.00 a gallon. I think it is now around $20.00 a gallon. Maybe with crude coming down, oil will back off a bit. If you are interested in the Rotella SB, most NAPA stores or Shell Rotella oil dealers either have it or can order it. Mystic 10W30 is a bit harder to find, however farms store such Orschleins, Bommgars, Blains Farm & Fleet here in the Midwest Carry it and I would imagine some farm stores in your area may have it as well You can go to Mystic (Citgo) website to find dealers in your area.

 

[DWCox]

Thanks guys for your input. I think you have made a pretty good case in my mind for synthetic--particularly the cold start-up issue. I likewise store the tractor in an unheated barn/shed, and cringe at the sound while letting it warm up.

I tried to chase this question down by surfing the "Bob is the Oil Guy site," but it is easy to get lost in a myriad of details and opinions and not find a direct answer to the type of applications we do. I did learn a good deal of helpful information about different greases though.

I am going to copy the responses in this thread and paste them into a word file before choosing my oil before the next change.

Sixdogs, thanks for your comments on the pond. It has been an enjoyable project and the kids have loved the whole process. The 790 will be the sole equipment used for the second pond--that and a middle-buster plow and box-scraper! I love the old-school design of the 790. It is a bullet-proof piece of equipment!

 

[JGY]

I cannot recall if there are any 15w40 synthetic blends.

I believe AMSOil 15W-40 PCO is a synthetic / mineral oil blend. A reported, slightly higher HTHS number than their 15W-40 AME "full" synthetic oil. I also believe the "preferred customer" price is -- and don't quote me -- $5.75 / quart.

Hope this helps ...

L8R

J

 

[sixdogs]

Sixdogs, thanks for your comments on the pond. It has been an enjoyable project and the kids have loved the whole process. The 790 will be the sole equipment used for the second pond--that and a middle-buster plow and box-scraper! I love the old-school design of the 790. It is a bullet-proof piece of equipment!

Keep the oil level up on that tractor and you couldn't hurt it if you wanted. Prob one of best tractors ever made and so widely owner pasrts will never be an issue.
Search this board's oil threads for zinc or phosphorus or others and you will get all you need for data.

 

[ihookem]

I had 15 w40 in mine and it hardly turned over. Went to Mobil 1 0w40 or 5 w40 and made so much difference I couldn't believe it. It get to -20 here but even at 0 degrees it starts much easier. One other thing, it might make the starte last longer and mine is several hundred bucks. Now I havee Amsoil 5w30 syn.