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IH Cub Cadet Forum * CCC and MTD Machines & Equipment * Is Synthetic Oil OK? < Previous Next >

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Dennis Frisk (Dfrisk) on Sunday, November 17, 2013 - 08:25 am:

WOW GERRY! You re-invigorated a really old post!

What Jim D said is true, synthetics are fine but I would not go over the recommended service interval on ANY engine when using syn. oil. It's still exposed to ALL the condenced water and deposits of combustion that the mineral oil is, so still gets dirty as fast. Circulating dirty oil is almost as bad as not circulating any oil at all,

NIC B. - One comment about your post from 2012. Diesel rated oils (API grade starting with a C)whether synthetic or mineral based have MUCH more detergent additives than gas engine rated oils(API grade starting with an S). Diesel engines make a lot of soot when they burn the small droplets of fuel and the oil has to clean up all that soot. It's one of the more important things that labs check for when doing oil analysis on used motor oil along with wear metals and antifreeze contamination.

I'm not sure what oil Dad actually used in the old FARMALL's before I got them but the first couple oil changes I did I used Rotella 15W-40 and changed the oil after 5 to 10 hours of running. I removed a L-O-T of sludge from both engines. I suspect he was using whatever motor oil was cheapest and on sale at Wal-Mart. He wasn't like that when he farmed with both tractors. Both the mineral based & synthetic Rotella oils are both C & S rated for use in both gasoline, LP gas, and diesel engines.

It's also funny, I use mineral based Rotella T 15W-40 in my '96 Ford diesel w/7.3L IH engine as well as all my old FARMALL's and my Onan B48G and K241 Kohler. but use synthetic Rotella 5W-40 in the K321 since it's freshly rebuilt. The extra ZDDP is good for the old Kohler's, Onan, and IH tractor engines since they all have flat tappet cams. But the 7.3L PSD has both roller cam followers AND roller rocker arms from the factory, so really doesn't need the ZDDP. But since the high pressure fuel pump runs off an extra lobe on the cam shaft with a flat tappet it's good that the extra ZDDP is there.

I run synthetic Rotella in the K321 because the synthetic oil has a MUCH broader temp. range than the mineral based Rotella. And air cooled engines with their unsophisticated cooling systems can run way too cold in cold temps and WAY too hot when worked hard on hot summer days. Even at $20 to $25/gallon I still change the oil every 30 hours of run time.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Clint McCall (Cmccall) on Wednesday, November 13, 2013 - 11:20 pm:

I wanted to add a few things about oil. As far as synthetics very few oils are synthetic, although labeled synthetic when in fact the are highly refined convention1al oil with a better add pack. Mobil 1 has went this route after a battle with Castrol in court over what a synthetic is. You can do some research on this lots of info, also a lot of arguments , theories etc comparing group III (hydrocracked= mobil 1) true synthetic group IV = Royal purple etc. I run Rotella or Delo straight 30 all year (temps here don't drop below 20*) the straight grade oils do not have as many polymer additives to obtain the multi-viscosity these polymers break down in my opinion much more so in air cooled engines. Also I have seen oil test data that has shown the HD oils holding up better, lasting longer, and better properties that many synthetics (grp III, IV). The HD oils are a really good bang for the buck for now, if people catch on the price will go up for sure.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Nic Bextermueller (Nbextermueller) on Wednesday, October 09, 2013 - 06:51 am:

Wow! I wrote that a year ago! Time flies doesn't it.... Where does it all go.

BTW, I'm still a firm believer in my statement below.

The 2013 pulling season is here! Visit to get the schedule and see all the event action and results. Lucas Oil now on board for the Championship!

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy joe knight (Jknight) on Saturday, October 05, 2013 - 04:28 am:

I use VW 50501 synthetic oil. Which is Castrol synthetic. Have used it in my 1810 since I bought it new. Have had no problems in 800 + hours.
I use Shell Rotella T in the 782D. Do not know what the previous owner used. I have only had it three years. Hour meter shows 860 but tractor looked like it had three times that on it.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Jeremiah Chamberlin (Jchamberlin) on Friday, October 04, 2013 - 06:53 pm:

Bill Bennett: I think the post to which Frank refers was from Nic Bextermueller on Thursday, October 25, 2012 at 09:14 pm

Nic wrote:
Begin Quote

Keith O,

The difference between auto 30w and Diesel 30w is the chemical makeup. But the short story is diesel has less detergents and more ZDDP (zinc). Auto's are nearly all roller valve train now and require less zinc (the slippery stuff in oil) and ZDDP and catalytic converters don't get along well so oil manufacturers have been required to remove most of it from car oil.

Diesels on the other hand still run flat tappet stuff and much higher valve train pressures that require more ZDDP than autos ever did. And since most are not required to pass an "emissions" tests, all the good stuff stays in. On a side note, you will find that nearly all new diesels require a separate EXHAUST fluid that gets passed through the converters to burn out the build up of the good stuff in the oil.

Most lawn and garden oil still has a high enough ZDDP count to work well. But the bottom line is diesel oil is better "oil".

Next time your buying oil, look at the little API stamp on the label and see what standards the oils meet. There will be a lot of letters on the auto oil and only a few on the diesel. So don't put diesel oil in the minivan unless you want to replace the cats.

I run Lucas SAE 30 Plus oil. It is specifically designed for the flat tappet, air cooled, low detergent type engine we use. It works great and is made right in Corona CA, USA. Another side note, I also use 2oz Lucas Upper cylinder lubricant and 2oz Lucas Ethanol treatment in every 5gal can of 87 octane I use for my cubs. It runs like a top and has noticeably more power, faster revs, and less noise than when I run out of those things.

Jonathan D,
Here's why the full synthetic oil is ALWAYS better. Imagine all the little carbon chains we call oil floating around in a Qt of oil. When that oil comes from dinosaur oil, there are lots of different chains of all different sizes. For the sake argument, let's say they are golf balls, baseballs, and soccerballs. All the little golf balls do nothing but fill space. Yes the lubricate, but they are small enough to slip past rings, valve guides, seals and just quickly get burned up or get stuck somewhere they shouldn't be. All those soccerballs are even worse. They are to large to even really properly lubricate and mostly get broken up or never make to the tiny spaces we call clearances. It's all those baseballs that do all the work we want, lubricating while stay where we need them.

Full synthetic oil is engineered to be ALL baseballs (all the exact same carbon chain and all the same perfect size). Its still oil, it's just engineered and formed in a lab instead of under a pile of rocks we call earth. So you are already noticing the benefit of full syn oil. Because you are no longer burning off all those golf balls and breaking down those soccerballs (becoming sludge) which is why Dino oil is so high in detergents, to keep those broken down chains from sticking to your engine parts, which ironically means its passing more dirt and less oil through the oil passages the longer it's run. Why do you think they make full syn's that can run 15k miles? It's not breaking down or burning up!

The 2012 pulling season is over.
Visit to see all the event action and results.

See you in 2013.
End Quote

I agree with Frank, it was a good post, and I saved it to my collection of "keepers."

Kohlers are kool

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Donald Tanner (Dtanner) on Wednesday, October 02, 2013 - 06:27 pm:

Jim Diederichs
My diesel truck takes 12 liters plus the filter and I would get at least 10th out of the oil before a change. There is a company here that use cheve trucks to haul trailers from the USA to here in Nova Scotia and have never changed the oil in the new trucks. They rely on oil annalist to tell them when the trucks need a change. one 2011 has 75 thousand klm on it and never had fresh oil and filter. I think the owner of the trucks is crazy and will pay big time for that.I expect to hear any day that the guys blew up a duramax diesel.

1 step forward 2 steps back always ! Later Don T

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Jim Diederichs (Jdiederichs) on Wednesday, October 02, 2013 - 05:02 pm:

It is fine to use synthetic oil if the engine manufacturer's change intervals are followed. In air cooled engines, if not changed on time, the syn. oil will lose the lubricating properties and gel up badly. Remember that air cooled engines depend on the oil for a portion of their cooling, not only air. Oil temps are much higher in an air cooled engine than in your truck or car's liquid cooled engine.

I have done warranty evaluations on engines that were using synthetic, and were not changed at regular intervals. It looked more like a black grease, not oil; had to scoop the residue out as it wouldn't even drain some of it.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Frank A. Currier(Northern Maine) (Fcurrier) on Tuesday, October 01, 2013 - 07:15 pm:

7,000 miles on "my" '98 Jeep 4.0 (w/158,000 "dino oil" miles behind it)and just dropped a quart. It was a scary thing to change to, but I'm now a believer. Someone here compared the molucules in synthetic oil to the molucules in dino oil. That was a good post. The 169's next oil change will be full synthetic Castrol (?).
We'll see. :-)

"Cubbers Without Borders" -- Never lose altitude, air speed and ideas at the same time. -- I ain't done, yet! :-)

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Bill James (Bjames) on Tuesday, October 01, 2013 - 05:51 pm:

I've heard it could cause seals to leak but thanks for bringing up old threads.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Bernie Pientka (Bpientka) on Tuesday, October 01, 2013 - 05:14 pm:

Anyone using synthetic in a kt17 series II ?

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Gerry Ide (Kide) on Tuesday, October 01, 2013 - 04:10 pm:

I've started using Mobil 1 synthetic in most of my small engines (my Harley uses HD synthetic, my Ford Truck is using Motocraft, but my 460 Ford is also using Mobil 1). I trust synthetics...

Iím a true believer in karma. You get what you give, whether itís bad or good.
- Sandra Bullock !!!

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Bill Bennett (Wbennett) on Monday, April 18, 2005 - 01:38 pm:

I bought some straight 30 weight to use for the time being. It made my wallet a little lighter ($7.35/Liter)

I'm sold on synthetic. My 15 year old Emglo compressor has new life since I switched. I was ready to give it away because it was so hard to run it without tripping circuits. Good as old, now.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Scott Tanner " NY has cows, too!" (Stanner) on Sunday, April 17, 2005 - 08:59 pm:

I've used castrol 5w50 full synthetic for 5+ years in my original, never been rebuilt 1973 149. no problems whatsoever. and it'll start at 0 degrees F!

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Travis "Lord Farquad" Schweizer (Tschweizer) on Monday, April 04, 2005 - 08:35 pm:

I've been running it in my plow tractors due to the fact that the engines seem to run plenty warm when working them that hard. It's a little more pricey though.

I'll part anything!!

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Steve Blunier (Sblunier) on Monday, April 04, 2005 - 10:21 am:

Some people use it...biggest problem (if there was one) would be oil consumption and/or additional carbon deposits on the head due to the lighter oil getting past the rings.......

I personally wouldn't be afraid of it, but I usually run dino 30wt in my stuff in the summer and synthetic 10/30 in the winter.

In the end it's your decision.

"Mr. Plow"
Running 8/9's & a 782 in Central, IL

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Bill Bennett (Wbennett) on Monday, April 04, 2005 - 08:54 am:

Is Mobil 1 full synthetic motor oil OK to use? The owners manual states do not substitute 10w-30, or 10w-40. Mobil says it can be used in a low ash situation, but wouldn't go against the owners manual on the weight. Any input greatly appreciated.---Bill

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