Mark Smith’s 2012 Ram

For certain areas of the country, it has been winter for a few months now, but other are just now in full swing of it. We figured this would be a good time to touch on a topic that most people don’t think about and that is fuel and protecting your truck in the winter.

Fuel that you buy in the summer isn’t the same as the fuel you buy during the winter. Refineries have multiple blends they use depending on the time of the year. The main reason for the difference in blends is the weather.

Naturally, you would think that cold weather means more power. The air is denser, so there is more oxygen per volume of air. More oxygen means cooler EGT’s and more power is the common thought. Unfortunately, while the colder air is great for oxygen content, it is really bad for fuel.

Issue 1: Gelling

Photo courtesy of Innovative Diesel

Depending on where you live and how long you have driven a diesel will depend on whether you have experienced fuel gelling or if you know about it. Fuel gelling is a process at which the paraffin’s in diesel fuel begin to crystallize enough to prohibit fluid flow. If you do a quick search on the internet, you will find people identifying many different temperatures at which this phenomenon happens (anywhere from 40 degrees to -20 degrees Fahrenheit). Why the inconsistency?

The primary reason for this is that the fuel across the country isn’t the same. Refineries add chemicals to their fuels to help prevent gelling. Fuels that go to the southern regions of the US, don’t see the same temperatures as fuel up north. So, they don’t see the same amount of protection. Even with the additives, fuels will still gel. One thing you can do is add an anti-gel additive to your fuel. These will help stabilize your fuel at lower temperatures.

Issue 2: Power and Economy

A down side to this winterization of the fuel is that the fuel has a lower cetane rating. Cetane is a rating for the fuel’s quality of combustion. It is actually an extremely important rating to know and one that most of us have no way of finding out. The cetane rating isn’t regulated by any agency and as such, there is quite a big swing between not only brands, but even within batches from the same refinery.

Rob Buttermore’s 2004 Ford F-250

If you have ever filled up somewhere and the truck felt a little peppier or you suddenly got a little better fuel economy out of the truck, that is because the fuel had a higher cetane rating. If fuel stations would start posting the cetane rating, it would be worth driving a few extra blocks and paying a little more for a higher rating.

Now all that being said, there is a point of diminished return. The average cetane rating from coast to coast throughout the year is between 38 and 45. Every couple of points increase in cetane rating is noticeable when you drive. So, while the difference may only be 7 points, just know that is a big difference. As the cetane rating starts to reach above 50 and into the mid 50’s the increase becomes less and less. To the point that anything above 55 is not worth the extra cost to make.

We were talking to Eric Eldreth from Innovative Diesel about this and he had this to say, “The winterized fuel does not provide the same level of performance as the summer fuel, so your mileage will likely drop while using it. A reduced Cetane rating reduces the ability of the fuel to auto-ignite, a process that eventually leads to lower fuel economy. This will cause a drastic drop in mileage on our light duty trucks.”

Eldreth mentioned that he recently written an article on his site that has a few tips to improve their economy. (Click here for the article.)

Justin St. Pierre’s 2002 Chevrolet

Blake Raham’s family vehicles.

Issue 3: Hard Start

Diesel engines are compression ignition engines. The process of ignition happens when the fuel being injected into the engine mixes with hot air. As the fuel is rapidly heated up by the air, it auto ignites. When the engine is cold and the air is cold, there may not be enough heat present to auto ignite the fuel. This is why manufacturers have installed grid heaters and glow plugs. These are designed to heat up the air enough to reach auto-ignition. If you are like many of us, we have removed these grid heaters and other restrictions to the intake trying to get more power out of our trucks.

What can you do? Well, at night you can plug in your truck. By keeping the engine block warm, the air will heat up more during compression helping to achieve auto ignition. This is, also, the time of year when people find out their batteries are bad and they are left out in the cold. Make sure your charging system is working well and your batteries are in good shape. The starter needs all the amperage it can handle to turn over the engine when it is cold.

Matt Zimmerman’s Chevrolet.