I have a 05 6.0 that is starting bad this fall/winter and have read many posts about useing 5W oil. I mentioned it to our head mechanic and he asked why none of the other trucks in fleet are having trouble with the oil he uses? Can someone give me some info to take to him? I think we are running a syn. 10W-30 or 40. I plan to print this off and bring it in to him. Thanks.

 

Most of us are using a full synthetic 5w40, verses a 10w30 winter diesel non synthetic for the starting and antistiction. In Winter I was using Motorcraft 10w30, summer pulling, used 15w40, for heat resistance and higher temp lubrication. Now the full synthetics in a 5w40 provide teh winter starting of a 5w cold, and the protection of a 40 weight for general operation. It is way more expensive, you can use Dino oil and its fine, just have to make sure you dont run 15w40 in colder temps, it starts hard for sure. For a fleet of vehicles, I am sure they will want to stick with Dino oil, for my personal vehicle, I use Delo 400 Synthetic, 5w40 it is a CJ4 rated oil. Really, this AM will be starting her at -35C or -25 F below 0, so its important to have the right oil.

 

I ran 15/40 in the winters for the first 2 years I owned my truck with no problems, I do run the 5/40 though now year round.

 

With a high here of -6 today (it's been in the -'s all week) I can really appreciate the switch over I did to the 5w40 Synthetic. It started easier after I initially changed it and it was 30 degrees then. Now with it being much, much colder I feel a lot better about having switched from the dino.

 

I switch over to 10w30 diesel for the winter. I'm too cheap to go with synthetic. I do my own oil changes and have been doing this for a while. The thicker 15w40 is what you want for the summer for better heat handling, but you don't want it in the winter. Not only hard starting, but you'll be in for injector troubles down the road. Edmonton's winter temps are cold enough -34C (-29F) last night and more of the same tonight. I don't have starting troubles, but I'm starting to get sick of the deep freeze and the first of winter isn't until tomorrow. I am so not retiring here......