Originally Posted by adfields
I ran 10/40 for years in Arizona and in Alaska (since 2000) I ran 5/30 year round but switched to that Valvoline Cummings synthetic last winter, I think itís a 10/40. I never saw any notable difference in pressures with a worm motor. On a cold motor cold starting you get more pressure and that is why they start so much better. For cold start the difference between 10/40 and 5/30 is amazing but with synthetic they start first hit at 20 or 30 below without being plugged in so itís well worth the money for me here in Alaska. I broke down and went synthetic after having to nuke a gallon of 5/30 in the microwave one morning so it would pour, synthetic is not nearly as affected by cold or hot temps.
Your motor has worms? I'd get something for that....
Unless you are below 0 degrees, just use the standard oil and plug in your truck at night. Or, bend over and pay the $$$ for the 5w-whatever synthetic.
My truck started the same in Milwaukee area (Jesus.. was it cold), as it does here in Texas. Just cycled my glow plugs, and bam.. fires right off. Let it idle a few minutes and since the truck was plugged in, the heater was already warming up the truck. Standard 15w-40 is the only thing that was been run in my truck.