How to Prepare Your F-250 Diesel for Winter

The main issue with diesel engines is gelling fuel in cold temperatures. What causes this to happen is paraffin is used in the fuel to raise the fuels British Thermal Units (BTUs).

Paraffin is wax in liquid form that is mixed with the fuel. Because it’s a wax, it won’t freeze solid, but as the temperature drops, it will begin to gel. At 32 degrees Fahrenheit, it will simply cause the fuel to appear cloudy which isn’t an issue in most cases. Once the fuel reaches around 10 degrees, it will begin to gel up.

Once the fuel has gelled, you will be left with a headache. The fuel lines, filters, and tank may be packed with this gel, and you won’t be able to move until the fuel has returned to a liquid state. The best measure isn’t to wait to let this happen. Instead, you will want to work proactively by treating your fuel with winter diesel fuel treatment.

If this issue is so troublesome to deal with, you might ask yourself why the fuel even comes in a state where it would react as such to the cold weather. The truth is fuel sold in northern regions already arrives pretreated to counter the effects of the cold weather. Though it’s still wise to work proactively, it’s not much of a threat in the rust belt. Southern states that don’t regularly get cold is where you will need to worry. Even if the days are warm, all it takes is an overnight temperature drop to find yourself facing a gelled-up fuel system.

Other than dealing with the fuel gelling up, there are other potential threats in the fuel system you will need to address. Over time, the fuel filters will draw in moisture and when the temperature drops low enough, the water in the filter will freeze up. Even treated fuel will drop in viscosity and the ice in the filter will work as enough of a blockage to starve the engine. Before winter hits, it would be wise to make sure a fresh set of fuel filters is in place.

To counter the cold start issues presented by cold temperatures for diesel engines, block heaters should be used. The heater on your F-250 is located in the front of the engine bay and is powered by an external source. The heater works to keep the engine block warm so any fuel entering has a better chance of igniting. They should be plugged in overnight so in the morning the engine will fire right up.

Moisture in the fuel system poses a real threat to diesel engines. This is why vehicles like the F-250 have a water separator installed. A water separator works to pull all the water from the fuel before it reaches the sensitive parts of your engine. This is a major help, but for proper engine operation, you will need to maintain it.

Luckily for us, Ford makes life easy by putting the Fuel separator in the same place on most F-250 trucks. It is located on the fuel lines just below the driver’s door near the frame. The only thing to keep in mind is the draining process varies from truck to truck. The 6.0 Powerstroke models will have a physical plug that requires an Allen wrench to drain. On 6.4 Powerstrokes, a switch near the drain valve will need to be flipped, and on 6.7Ls you will work with a thumb wheel attached to the valve.

You can opt to rely on the warning light that signifies when the separator must be drained. Though, many Ford owners recommend draining the separator at least once a month. When you drain the water from the system, be sure to use a drain pan to catch the water that trickles out.

It may feel a little redundant to work over a cooling system prior to the cool weather, but it’s still worth addressing. You will want to check all your physical connections in the system and the condition of all the hoses. The condition of the fluid will also need to be checked. If you know the coolant is due for a change or you caught yourself sneaking water into the system, you will want to change it before the temperature can get low enough to freeze anything.

The battery will be taking on a lot of stress through the winter. Most of a battery’s power is used to start an engine up and when you throw high compression, big displacement, and cold weather into the mix, the weight it carries greatly intensifies. Before the winter hits, and you find yourself in a sticky situation with a dead battery, you’re going to want to make sure your batteries are up to snuff.

Batteries are liquid filled and the liquid is mostly water. This means that a battery with a low charge can physically freeze. It’s also susceptible to losing efficiency as the temperature drops below freezing. If you are running older batteries, you may want to consider replacing them before winter even has a chance to stick the landing.

If your battery is fairly new or brand new, this does not mean your work is done. You will want to make sure you have good clean connections to the battery. This means you will want to take the time to clean your battery terminals. Having a good solid connection can be the difference between being able to start the vehicle or not. If you do not intend on using your truck for prolonged periods during the winter, you will want to disconnect the battery terminals during storage to work against any loss in charge.