Preparing a Diesel Engine for Winter

Preparing a Diesel Engine for Winter

Preparing a Diesel Engine for Winter

Now is the time to switch to the SWEPCO 501 Premium Diesel Fuel Improver Winter version to protect your equipment when a cold snap occurs and possibly causes problems. Once a fuel has gelled, it must be warmed up and completely thawed to treat it.

501 Winter improves the Cetane Number in diesel fuel for easier starting, shorter warm up time, and less white smoke at start up.

SWEPCO 501 Premium Diesel Fuel Improver Winter version contains wax modifying chemistry to lower the gelling temperature of the fuel. Diesel fuel has a cloud point, where the wax comes out of solution and form sheets of solid wax that clogs filters and will shut down an engine. The 501-wax modifying chemistry helps keep the wax crystals small so they will pass easily through filters at lower temperatures. The wax present in #2 diesel fuels are long chain hydrocarbons that provide the BTU’s for power and fuel economy. #1 Diesel fuel is wax free, has a very low gel point, but has lower BTU’s, power, and fuel economy.

#1 and #2 diesel

Usually the refineries blend the #1 and #2 diesel during the winter so that the fuel will flow in cold weather. Problems arise when winter blends are not delivered soon enough or a truck fills up with straight #2 diesel then encounters a cold snap or travels north into colder weather.

Bulk storage

Bulk storage tanks do not have mixing capabilities so when a winterized fuel is added, depending on how much fuel was left in the tank, it may be diluted to where it is not effective or not make it into a fuel tank of a truck or off road equipment until several fill ups later. #1 diesel has less lubricity which is hard on pumps and injectors, SWEPCO 501 Premium Diesel Fuel Improver Winter version contains to lubricity additive to help protects these parts.

Refineries now use hydrocracking and hydrotreating to obtain more diesel fuel and gasoline out of a gallon of crude oil than ever before resulting in lower quality fuels. These fuels still meet the minimum fuel specifications but do not always provide the performance needed to operate well in severe weather conditions.

Water traps and fuel / water separators

This is also a good time for some preventative maintenance. Water traps and fuel / water separators should be emptied to prevent them from freezing. Fuel filters should be checked for water, and oil analysis samples taken to make sure the oil has not started to thicken, making it more difficult to start on a cold morning. Water in the fuel system will clog lines, filters, and injectors. 501 Winter will help keep water from freezing in the fuel system and the less water present, the better everything works. Checking coolant levels and other critical system like EGR valves, turbocharges, belts, etc. will help prevent weather related shut downs.


It was not long ago that diesel trucks would idle while the driver sleep, ate, or was off duty during cold weather to keep the engine and fuel warm. This helped to keep trucks and equipment running during severe weather. Recent changes in air quality regulations now prohibit trucks from idling during off duty hours in many states, resulting in cold starts and cold related shut-downs. Many truck stops now offer “plug-in” service to keep the truck and driver warm during off duty hours. These services still do not address the fuel system, only the engine block and cabin.

Off highway equipment is usually left out in the elements at the job site requiring more attention to maintaining the fuel system. Often more time is spent trying to start the equipment than producing with it.

Gasoline Engines

SWEPCO 503 Premium Gasoline Improver helps maintain a gasoline system for easier starts and addressing alcohol/water based issues such as fuel line plugging and ice formation.


As always if you have any questions please use the contactform or send us an e-mail. we are here to help you!

SWEPCO 308 Premium CJ-4 Plus 5W-40 -

Source: SWEPCO®
Southwestern Petroleum Corporation®

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