running 15w-40 in engines?

Discussion in 'Lawn Mowing' started by TClawn, Aug 9, 2005.

  1. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

    As we all know, oil shears, resulting in a lower grade of oil (a 30w becomes a 20w) after a few hours.

    with this in mind, would it be a good idea to switch to a XW-40w oil? I figure after a little while, you would be down to a 30w, which is what the mfgr. recomends.

    do any of you run 15w-40 in your engines? do you have engines with over a 1000 hours that have only been run with 15-w40? have you had any problems with the engine that could be trace back to oil problems?

    is there any reason I should not run a 15w-40 oil in my engines?

  2. Albemarle Lawn

    Albemarle Lawn LawnSite Bronze Member
    Messages: 1,544

    It really simplifies things if you operate gas and diesel trucks and equipment.

    Diesels must have oil with a "C" in the rating (for "Compression" ignition), and that is what you get with 15w-40.

    Gassers can take 15w-40 or other grades, but diesel require 15w-40 or a good synthetic 10w-30, 10w-40, or 20w-50 oils such as Mobil1 with a "C" rating.

    I have a Kohler 27 HP runs on 15w-40 over 1000 hrs and going strong.

    BTW in Hawaii its so warm and consistent temps your best oil is Mobil1 15w-50, use it in EVERYTHING except tight tolerance car engines such as Hondas.

  3. PTP

    PTP LawnSite Bronze Member
    from Tulsa
    Messages: 1,399

    The most critical time that you need the oil is in startup. Those valves, lifters, and all of that are dry. They need oil now - not in a little while. When you put heavier oil in, it takes just a little longer for it to reach those places which means that they are running dry for longer periods of time.

    Stick with the recommended stuff so that you don't end up outsmarting yourself.
  4. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

    what about shell rotella T 15w-40?

    what oil do you run?

    I would be afraid to run 15w-50 in all my engines. it's a bit too far off the mfgr's recomendation.
  5. 65hoss

    65hoss LawnSite Fanatic
    Messages: 6,360

    I run Shell Rotella 15w-40 in everything. Trucks(all gas), mowers(kawis), aerators(honda), tractor(ford).

    One of my old kawi 23hps has over 1000 hours on it. I sold it to a friend and its running strong. All other mowers have between 500 hours and close to 1000 with ZERO problems.

    I did tons of research and years of motor building to make my oil choice. Not going into all that here, but I did talk with some powers that be at eXmark and Kawi. Not some rep, but actual engineers at both in person. In a nutshell, both do extensive motor testing. I discussed using the 15w-40 with them. The answer I got, it will not hurt anything. May very well extend the life of the motors considerably by having the better protection. These motors are run in the harshest environment possible. Air cooled motors in high heat, extreme dust, humidity, sometimes extreme cold, whatever the case, the 15w-40 would flow just as fast at startup and give a better protection at worktime.
    With that said and them stating that it could add several years of life to the motor I run it only. Nothing better than the Heavy duty oils designed for heavy duty service in a trucking industry that has spent millions on R&D.
  6. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

    do you run any kohlers with that oil? I remeber that the kohlers would develop a knock if you ran dino or anything over 30w.

    I am definately going to try it on the briggs and honda engines.
  7. 65hoss

    65hoss LawnSite Fanatic
    Messages: 6,360

    No kohlers anymore. I do know a few people that have them and are running the Rotella in them. No problems.
  8. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

    I will give it a try. thanks a lot 65hoss.
  9. butler L&S

    butler L&S LawnSite Member
    Messages: 44

    I run 10w30 during the cooler months and 15w40 late June - early Sept. I have not had any problems and we put nearly 500 hours each season on a few mowers. I have a 25 Kohler on a Lazer and have not heard any knocking while using the 15w40. I think the key is timing... I would expect to hear knocking if I was running 15w40 when the temp was below 40.
  10. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

    ok, you must understand that my temps NEVER drop below 60 degrees. the temp for starting in the morning, is around 75 degrees. during the height of the day, it is between 85-92 degrees.

    65hoss, or anyone else who knows, will I have to get a different micron filter to run the rotella 15w-40?

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