Join Date: Jul 2005
Location: Cody, WY
Feedback Score: 0 reviews
I've been running 5w-40 (Rotella T6, Mobil 1 for Turbo Diesel Trucks and Delvac 1) in my 2005 since 2005.
There is no reason whatsoever to change to 15w-40 during summer. Your batteries, starter, FICM and injectors will all last longer when your engine pumps 5w oil on cold starts. That's cold starts in winter as well as summer.
I've read countless threads about guys plugging in block heaters at +45F. Really? Try 5w-40 instead. I've cold soaked my truck at -25F for 8-10 hours several times here in Northwest Wyoming without plugging in the block heater and have experience no starting issues.
Twice after a -25F 10 hour cold soak I started my truck at the same time another 6.0 was starting his. Both times the other truck cranked for a while and wheezed to life bucking and jumping around. It was painful to watch and hear. Once, the driver came up to me and asked how I got my truck to start so quickly and run smoothly. I asked what oil he was using. 15W-40 conventional.
Using 5w-40 is the easiest cheapest thing you can do to enhance the reliability of your truck. The second is keeping your batteries hooked to a Deltran Battery Tender.
2005 F250 4X4 SD R/C Power Stroke / Torqshift
Oxford White, Medium Flint 40/20/40 Vinyl, Prefered Equip. Pkg. 600A , 3.73, Limited Slip, XL Decor Pkg., Jeweled Headlamps, Chrome Rear Step Bumper, 9600# GVWR Pkg., Engine Block Heater, Sliding Rear Window, Speed Control / Tilt Wheel, Camper Pkg., FX4 Pkg., Air Conditioning, Forged Aluminum Wheels-17", Tow Command, Telescoping TT Mirrors. Using this vehicle to produce an ambulance voids Ford warranty. Added: Ford factory upfitter switches, Go Industries Rancher Grill Guard (hammered powdercoat), Hella 4000 Rallye lighting (two Euro Beams), SnugTop Super Sport camper shell, Jotto Desk & Escort Redline Radar/Lidar Detector.