As another Canadian winter approaches, can problems with diesel exhaust fluid (DEF) be far behind?
Bill O’Ryan, senior manager of DEF with the American Petroleum Institute (API) says drivers and fleets can take steps to minimize the risk of DEF performance issues in the colder months. Because DEF is a blend of urea and purified water, it is prone to freezing and the related expansion that entails.
O’Ryan says to purchase only DEF that is licensed by the API, which has guidelines in place for purchasing and storing the emissions-fighting liquid.
When purchasing DEF at a truck stop, he advises to ensure the DEF brand and manufacturer are clearly identified. Purchase DEF that’s stored away from direct sunlight in a cool, dry place. Inspect the packaging for signs of contamination or damage, he says, and look for the API certification mark on the container.
Choose DEF that hasn’t surpassed its expiration date, and if one isn’t displayed, request DEF that has been recently delivered, O’Ryan adds.
When storing in the truck, keep it away from hot areas and direct sunlight. In the shop, find a cool, shaded area where DEF will last for 12 or more months. O’Ryan also suggests fleets cycle through the older DEF first to ensure it doesn’t expire.
When filling the truck’s DEF tank, use dedicated equipment, not funnels, pitches or hoses that are used for other liquids. Dispensing equipment should be cleaned with distilled or deionized water, followed by a DEF rinse.
In the winter, if DEF freezes don’t add additives to the tank to help it melt, O’Ryan says. The DEF tank on a vehicle has a heating element that will quickly thaw the liquid and it will continue to be on spec’ after thawing.
“Like water, DEF will expand up to 7% when frozen and can damage a storage tank if it is full or nearly full when it freezes. Keep the tank less than full to eliminate this risk,” O’Ryan says.
The API has recently created a DEF Consumer Guidance resource page with more tips on handling it year-round.
