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Use 5w20. The thicker oils may not hurt the engine too much ordinarily, but they have a delayed circulation time in cool weather. This can cause lack of lube on overhead cam engines and damage camshafts and valve train.
It also turns out that the greatest benefit of pressurized oil in engines has been its ability to cool bearings. This, of course, takes a high flow rate to be most effective.
There is old wives tales still circulating around how thick oil can cushion bearings. Any modern day bearings that need "cushioning" are basically shot, usually galled by overheating, since the old, slow thick oils often failed at proper cooling. A bonus, fast flowing oil lasts longer now that it is not overheated by exposure lag under high heat stress. Oil thickens from heat as it ages and does not do as good a job cooling bearings. This thickening is one of the reasons automatic transmissions need frequent replacement lube, especially after abuse. Synthetic oils led the way to oils and blends that now resist thinkening.
Some of this knowledge became evident when it was noted how well automatic transmissions avoided wear with thin oils and how sensitive they were to cooling. This is opposed to manual transmissions that used to often use 90 weight gear lube, many of which now also use thinner oils.
Wes
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Days spent camping are not subtracted from one's total.
- 2019 Leprechaun 311FS Class C
- Linda, Wes and Quincy the Standard Brown Poodle
