You should check out bobistheoilguy.com for some proven info.

As for me I get the Valvoline Premium Blue and stock up when it hits a sale. I start plugging my truck in, on a timer that kicks on at 2:00 am, when temps drop into the 40's at night. My truck has sat in -15 overnight, plugged in, though.

If youare worried about thinness of a lighter viscosity, remember that at operating temps ~190F, any motor oil is much much thinner than a bottle of 0W-50 etc at cold start mild temps.

If I can't plug it in, I start it and let it idle for quite a while before loading it up. What that video doesn't show is that cold oil under 50-60 psi, which would move it a little faster I think....

 

Yes I have been looking at bobistheoilguy. I haven't found anything too concrete yet. And yes I see what you mean about adding in the pressure factor pushing the oil, but it still seems like it would have an awfully hard time getting through the tight tolerances inside the engine when that thick.

I plan to plug my truck in overnight always but I won't be able to during the day at work. If you were in that position, would you run lighter weight or a synthetic oil? Or at least a syn blend?

As far as what you said about the oil being thinner at op temp, does that me that the 40 is actually thinner than the 15 or even the 5? What I'm asking is, is the lower number thicker? If that's the case, I can't see any reason to not run the 5w40 year round. I'm still trying to learn all the ins and outs of oil.

Thanks for all the help!

 

I used amsoil 5W40 year round for many years in my 2001 and now with my 2011 it says in the paper version of the owners manual that you MUST use 5w40 in temps below -18c if not engine damage may occur. I tow heavy and still use 5w40 synthetic year round.

 

40 is heavier than 5. Multi-viscosity Oils have a polymer in them that when it heats up the polymers curl which in effect makes the oil thicker.

So 5w40 acts like a 5 weight when cold and a 40 weight when hot.

If your temps will get below 15F, i would be using a full synthetic for sure.

We get -40 temps here so that is why i use 5w40, going to try 15w40 syn in my 03 this year (it has dual batts vs only one in my old 1st gen).


So as you can see, the "hot" weights of either oil is the same. Its only the "cold" weight that is different, use what is needed specifically for your cold starts.

 

Well thanks for all the great info guys! I guess I should just make the switch this winter and stop worrying about damaging the engine as i will probably do more damage using 15w40 than 5w40, or so it seems after reading all your comments.

 

5w40 will definitely not harm anything, only drawbacks are you might hear a bit more clatter (subjective) or leak a bit more. Makes cold starts sooooo much easier, last winter had a wake-up around 0 F (-5 overnight) with no block heater and it fired up pretty smooth, old 12v and all. Might have the video kicking around...

When it warms up and it leaks more, I top off with regular 15w40 to thicken it up.

Found it-

 

I run the 5/ 30 synth diesel oil from Amsoil also, been using it since the rig had 5k on it. I also have an oversized full flow and a bypass filter for the oil. It's a lot of filtration but I only change the oil once a year and want my engine to run till the body falls off. I had to be at out 1000 islands station in Alexandria, a few mile north of you in December a couple of years back and didn't have any issues. I clacked a bit and blew white smoke until it came up to temp but the oil pressure was just a few lbs over normal even though it hadn't been over 5 below all night before I started it.
I do run a radiator shroud all winter though because without one I can't get any cab heat and my milage sux. I just use a piece of cardboard that fits between the radiator and the intercooler with about a 1 foot square cut from the center to keep a little air flowing and cool the fan clutch.