Most lawn equipment wont be operated below 32f maybe many manufacturers therefor don't recommend or see the need for multigrade where cold starting benefits from lower oil weight. Synthetics are proven to reduce wear, something many small engines need because of poor design. My generator recommends synthetic. Many small cheap motors only have a design life of 250-350 hours, commercial users need more and do benefit from synthetic.
Rich256 wrote: ..
I am not sure, but I believe that is backwards. I believe the viscosity improvers make thicker than it would be otherwise when it is warm.
That part is certainly right. Why is it that so many people get that part backwards?
You are absolutely right. My mind was working backwards. As I remember the polymers used for multi grade are elongated and kind of curl up as they get cold.
When Mobil 1 first came out I was having oil problems when pulling a trailer over high mountain passes. Even with 20W50, I would be down almost a pint or more after going over a high pass. When I would open the filler cap fumes would come out. I decided to give the Mobil 1 (only came in 5W20 at that time) a try. Much to my amazement my oil usage essentially disappeared. My theory is that engine was running so hot it was vaporizing the oil.
I read where it takes about twice as much polymers to make 10W40 as it does 10W30. It caused a lot of stuck rings in hot running engines.
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For that, no argument here!! I didn't catch what level of JD it was. Guess even their pushers (if they even make those) are decent.
Don't need the warranty being argued because it's claimed the customer used inferior oil. I'd even keep the oil receipts!
Another thought that occurs to me. Small engines, like lawn mowers, don't have oil pumps and therefore you don't have bearings that are pressure lubricated. They don't have the tight clearances that bigger engines have, and therefore using a straight 30w probably doesn't hurt anything. In a bigger engine, if you switch to a thicker oil, tight clearences that were lubricated with the thinner oil might not be lubricated with the heavier oil, and will wear. You go back to a thinner oil and you might experience oil consumption. This is what they taught in internal combustion engine class I took many years ago - not sure if anyone has actually proved this in the field or not.
So, any general consensus? Stick with a straight 30 synthetic and don't worry about it?
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