What oil to use in F250 6.0 diesel when cold?
 

I use my 2004 F250 6.0 diesel truck all winter to pull a gooseneck horse trailer loaded with sled dogs. My truck is having a hard time starting lately since it has been getting colder. When I plug it in it does start better, but I worry about when it has been sitting in all night in the middle of the nowhere when I am running dogs. This is a new problem, just in the last couple of weeks.

I've been reading a lot about the injectors needed to be replaced in 2004 models? If the injectors are bad could that make the truck start rough?

What weight oil should I be running in extreme cold? I did replace both batteries last year. Are there others things I should mention to my mechanic to look at?

I am by myself with 20 dogs alot of the time and don't want to get stranded.

Maggie

Use Rotella T6 5W40 synthetic.

Agree with JC. Use a good quality 5W40 syn year round. Your truck will thank you for it!

Rotella is fine. I use Mobil 1 Diesel Truck myself year round and have since the 10k mile mark. I've got 93k miles now and she's still going strong with good oil analysis'.

I agree with the above posts. I switched and it does wonders in cold weather. How bad are your cold starts? If their rough starts, you could have FICM or Inject issues.. BTW even if you switch to the Syn rotella, still change it at the 5k mark

Great point IEH!

I agree with using synthetic 5W40, make sure you use the right API spec fpr diesels. As far as OCI goes, I have been running Schaeffer Supreme 9000(full synth 5W40) and I get good oil analysis reports even at 10K miles. It's still at 40 weight even though the 6.0 is known for shearing some oils down to 30 weight in 5K miles or even less. I've had Rotella Synth shear down to 30 weight before. That said, I still change oil at 10K even though the reports say I can continue to run it.

Another issue might be stiction in the injectors. I've used Hot Shot Secret when I change oil and have not had any issues since I started using it. There are several threads here about using HSS, and Chris is a great guy to deal with.

Cold starting
 

I was having the same trouble with the cold starts. My wife took the truck out of town and forgot to plug it in. The 5w40 Rotella T6 and Hot Shot Secret was in the crankcase. Ended up the FICM was out and replaced the module. All is well now. Started well in minus 15 degrees F. Good Luck!
Harold

Question. If 15w-40, 5w-40 & 0w-40 is all 40 weight summer oil why not run run 0w-40?

This thread is like 8 years old LOL. OP is probably long gone!