Quote:
Originally Posted by CADplans
Running these tractors for light duty, oil weight does not matter, multi weight oil is great.
The recommendations of multi weight oil should be used with the understanding of what you are putting in the engine.
10W-30 is 10 weight oil. 15W-40 is 15 weight oil. Period.
The oils have modifiers in them that can variably "thicken" the oil as the temperature goes up.
The thickeners are very effective up to a certain temperature, designed and perfectly acceptable for WATER cooled engines.
Above this certain temperature the thickeners fail, and, the oil reverts back to 10 weight (or 15 weight).
This is what happens in a air cooled engine under a normal load. The engine operates above the thickeners temperature capability.
You will be running your engine on 10W oil!!
The engine manufacturers state 30W for a reason.
They want your engine protected when under normal load conditions.
Run the oil you want, mine get 30W. IMHO
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Your whole theory is backwards. This was taken off of the Amsoil website.
OK . . .What does a 5W-30 do that an SAE 30 won't?
When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.
