Cheapo synthetic is $22 or so a gallon. 3 gallons mean $36 extra...

Buy Valvoline fully synth diesel 5w-40 at a farm equipment store.. they are cheap, but they work.

 

Hey Headviking how long have you been useing synthetic?

 

about a year now

 

IHbase had some good advice. I don't use synthetic. Ford recommends 10w30 CJ-4 rated for diesels. That's important, not just any 10w30 will do. It's in your 6.0 owners manual. 15w40 in the cold weather will give you problems. Expensive ones too. 10w30 has been working in my truck for 4 years now and our winters routinely get down to -40. You still have ot plug it in though.

 

bismic has the reference to this... I think...


Ford changed recommendation to 5w-40 HD synthetic after Motorcraft came out with the product.

 

True, synthetic is always better, but I haven't been told anything about the it from my ford dealer where I buy the oil. I change my own oil and have been going to diesel 10w30 when the weather starts getting down to freezing mark. It's been working for 4 years now. I don't have starting issues and my engine runs great. I don't know if I would change my habits at this point.

 

I ran dino rotella 10w30 for the past 3 years in the winter. Switched to shell 5w40 syn this winter from what I have read. I have noticed no difference in cold starting or the engine being quieter from 10w30.
Will go back to 10w30 next winter.
Just my take.

 

Wait until you hit -35F

 

-46C (-50.8F) last week. No problems starting or running. Although the cab sounds like a tin can until it warms up. I hate winter...

 

[quote=Pitcher;8246535]Got this off the Gulf site FAQ, who know's maybe they are wrong...

"5. We have come across an oil having a 20W-40 rating. What does 'W' stand for ?
This is the common terminology used to indicate a multi-grade oil. 'W' signifies the winter rating of the oil, showing that it will perform well in cold weather. The lower the number prefixing the 'W', the lower the temperature the oil can withstand. Thus 10W- indicates a lower viscosity at low temperature than 20W-. The second figure shows the viscosity at 100 C, which is close to the bulk oil temperature in most water-cooled engines."

FAQ's : Gulf Oil Limited

Or off ehow.com:

What the Numbers Mean
The "W" stands for winter, and the number before the W represents the oil's viscosity at zero degrees F. The number after the W represents the oil's viscosity at 212 degrees F, which is the upper temperature range of a typical engine.

So then what is the viscosity of SAE 30 @ 0*?

 

+1 for the synthetic.

I switched to Shell Rotella T 5W-40 full synthetic last year mid-winter. I live in Wisconsin also, and we had one of the longest, coldest winters in quite some time last year. I noticed an immediate difference in cold start situations. Obviously the truck still needs to be plugged in, but it still started on the first try every time. I bought mine at Wal-Mart for $19.99 a gallon. That's a pretty small price to pay for the extra insurance IMHO. The nature of the Power Stroke injection system causes the oil to be sheared down rather quickly. The cost of replacing an injector or worse makes the justification of a good quality synthetic oil a no brainer. The oil is probably the most important part of the PSD engine! And everyone here is well aware of the service reputation of the 6.0L PSD! So why not take good care of it!?

 

I would use it if I could get a better price on it. As I said before, I go with what's listed in the manual for the 6.0; which for this climate at these temps is 10w30 dino. The Motorcraft is about $2.79 per litre. That same litre in the Rotella synthetic is about 9 bucks and change. I don't know why we get hosed so bad on the price when we produce the stuff just down the road. Probably the same reasoning that has us paying more for fuel here than those we sell it to.

 

Ya know... then you are in a "it ain't broke..don't fix it" mode.

 

30 weight is 30 at any temp.

+1 on the 5w40 syn, my bro's is running 0w40 and has been for 200000 Km, thats why its a 2004 that is still running. No injector or HPOP problems. Cold starts with 15w40 means HPOP failures and injector stiction.

Dont run it and start it at -20 F or below and you will be going to the shop, its just a matter of time.

 

The 0w 40 Shell I looked at wasn't certified for PSD 6.0 2005...

What is the C whatever rating?