General Question about Oil Changes

Discussion in 'Small Engines' started by infj23, Sep 28, 2016.

  1. infj23

    infj23 Sr. Member

    Dec 22, 2006
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    North Carolina
    Hello all,
    The mowing season where I live starts about late March/early April and ends by November 1. I typically change the oil in my mower (it's a Toro zero turn with a Toro-branded engine--has an oil filter) once a year. This is residential mowing only. No commercial use. I probably mow about 3 times in two weeks in the middle of the season and less frequently towards the beginning and end.
    Question: when should I change oil? Mid-season, sometime in July? Or after the last mowing of the year? Or before the first mowing of the next year? Or does it matter?
  2. nickb2

    nickb2 Wrench. I help when I can

    Nov 22, 2008
    Likes Received:
    northern car tech
    Schefferville, Qu├ębec, Canada
    Personally, I think used oil should never be left in any sort of engine when going to be idle for many months.

    As the oil will be accumulating carbon deposits, creating sludge from condensation, hence trapping moisture in the and about the molecules during the operating period and promoting particle sediment during prolonged dis-use. I find it is better to change the oil just after the extended use, before the hibernation period so to speak. New oil doesn't break down as fast as used oxidized oil when sitting over time.

    Proof is that you can have pints lying around for years on a self and good to go. I wouldn't say the same for oil that is oxidized. You can see that if you leave some used oil lying around in the back of the shed, a thick layer has dropped to the bottom of the container. That is what will happen in the mower. Alot of cars that sit for long periods of time with used oil in them rot from the inside out due to this.

    Oxidation, nitration and sludge are the worst things that can happen to an oil. So having that sit in your mower over the down time may lead to premature parts corrosion due to oxidation in the molecules of the oil. Oxidated oils will have increased hydrogen in suspension. Hence moisture.

    Anyways, I am not a scientist, but from my experience better to have that crank case full of new oil over the winter than have that old crap eating away at the inside over the winter. I don't think the oil would break down in a sealed environment while not in use. So, there is my opinion. And as I say often, opinions are like arseholes, everyone has one.

    Maybe someone else has another valid opinion that is worth listening to.

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