|01BIRDDOG said: (quoted from post at 09:42:18 11/29/12) OK after all the above post and all have merit is there one oil to use in areas that low would be "0" and say avg. would be 40 over the winter. I have never had a engine failure due to the quality of the oil by itself in all my years and this ranged from P&W R985 radial engines to 9200 RPM Harley XR 750 engines. But back on our 8n's--------what oil for above temps i listed.|
My opinion assuming we are talking an engine in good mechanical condition and your temperatures are 0F and 40F is the grade that has been the general purpose all-season standard in the vast majority of engines for over two decades now - SAE 10W30. Or possibly a bit newer (and probably more expensive) SAE 5W30 if you get much more than one or two days/nights in single digits.
Bottom line is an N will be happy with just about any SAE 30 oil. Because they are flatheads they are less susceptible to cold weather damage caused by overly thick cold oil but that doesn't mean they won't benefit from properly chosen grades on both ends of the temperature band. Easier starting and lower fuel consumption are two immediate benefits that come to mind. That said anything heavier than SAE 30 on the hot end is almost surely just wasting fuel. And anything lighter than 10W on the cold side is probably wasting money unless you live well north of the Mason-Dixon line and have extended periods of sub 15F weather.
TOH This post was edited by TheOldHokie at 08:30:37 11/29/12 2 times.