For cold wisconsin weather should I put in 10w30, 10w40 or 5w40 oil. I dont want to use synthetic because of the $$$.

 

I noticed a huge difference in cold weather start up last week when I switched to 5w40

 

Step 1: Open glove compartment
Step 2: Locate Owner's manual packet
Step 3: Open packet
Step 4: Locate Powerstroke supplement
Step 5: Read
Step 6: Locate chart depicting recommended oil viscosity at different ambient air temperatures.
Step 7: Locate where your climate falls on the range
Step 8: Select appropriate oil

-mike

 

I don't think you will find 5w40 in anything BUT synthetic (maybe semi-). But FWIW, I think you ought to reconsider and USE the 5w40 synthetic. However, if you are set against it, use 10w30 in winter, 10w40 summer.

 

I am buying 1 gallon of Valvoline 5 40 synthetic for $22 where I am.

 

x2 on reconsidering the use of synthetic oil. The extra dollars provide you with significant additional protection for your investment.

 

Quick question: I was under the impression that the "10W" was the cold weight. i.e. I believe the "W" stands for Winter, and the "30 or 40" was the hot weight. So with that being the case what is the benefit of switching the above oils between seasons?

 

W=weight, not winter. 5w40 will give you a 5 weight oil with protection of a 40(something like that). You could run the 5w40 during the winter and switch back to 15w40 for summer. The truck will start alot easier running the 5w40 in the winter.

 

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.

What Does 10W40 Stand for on Oil Containers? | eHow.com

 

oops, guess I'm wrong!

 

Wow, I never new that, if we were in the bar, you would have won quite a few beers off of me! Thanks!!

 

Believe it or not... I have won a few bet's on that one over the years!

 

And now you should also understand why there is a 20W20 oil.

 

I run Rotella-T 10w-30 in both my X's all year long and Rotella-T 15w-40 in the F-350 (it HAS to be pluged in to start below 10 degrees if it is not in the shop) all year long in Minnesota. I would like to run Rotella T 5w-40 all year long but i can't see paying 10 bucks more a gallon for synthetic, i personally don't think it's worth that much more money. Just my opinion!

 

I forgot............what was the price to fix a Diesel engine. We paid heavely for these engines, why not pay an extra $10 per oil change to maintain it. I on the other hand am looking for maybe even a beter sync engine oil, researching "AMSOIL 5W40". Just the way I feel.