Who is using Mobil 1 Delvac 15W-40 ? Analysis question also.

[IH3444]

If the OP oil is what you are using, then a full synthetic oil flows as well as a regular 10w-40 oil. Plus a full synthetic oil has more real oil in the container than a regular 10w-40 oil. The regular 10w-40 oil uses more what they name extenders to cover the 10w-40 range. You really need to go to Bob Is The Oil Guy site and read a lot to learn all this.
The bottom line is what the oil at low temps flows at, and then add 20 degrees F for pumping temp. I do agree to stay even then also with in a safe range. If the oil flows at minus 42F, and pumps at minus 22F, then I would only use it to possibly minus 5 to 10 F. At those low temps I would also use a block heater so the oil would be flowing through a warmed oil galley so it gets to where it's needed quickly. Most engine wear occurs with in the first 20 seconds after start up. Synthetic oils also have better clinking properties that regular oil. I took my VW diesel rabbit to get the valves adjusted once at a shop and the technician asked me after adjusting the valves on a hot engine what oil did I have in it, and I replied Mobil 1 full synthetic. Why do you ask? He said he had never adjusted valves on a hot engine that still had a coating of oil on the camshaft. He said oil just runs off hot engine parts right away, and the parts are dry to the touch.
The 5w-40 full synthetic oil is what I use. Rotella, T6.

 

[Bearcat81]

agree, i'd be using 5/40 in your ND climate. what grade oil have you been using?

Definitely - I used 15w40 Delvac (the old formula-not synthetic, etc.) several (10+) years ago when in southern Missouri- cold winter=blue smoke. Switched to a 10w30-(not Delvac--couldn't get that weight??) No more problems. Just switched to MFA (Mo. Farmers Assoc.) 10w30 semi (cheaper than Delo--better ASE specs, cheaper oil analysis...)
Delvac, Delo all good; I used a the wrong weight initially...