Diesel engines, known for their great fuel efficiency, are sensitive to cold temperatures. Instead of using spark plugs, as gasoline-powered engines do, diesel engines ignite fuel using a process called compression ignition, which generates a lot of heat. As such, diesel engines operate effectively at temperatures between 80 and 110 degrees Celsius (or 176 to 230 degrees Fahrenheit).

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That’s why winter mornings can be tough for diesel truck owners, especially when temperatures plummet. Cold weather causes engine oil to thicken and diesel fuel to gel, a condition called “gelling.” This makes it harder for a 6.7L Cummins engine to perform at its best, if at all. This is where an engine block heater comes in handy.

A block heater is one of the best ways to start your diesel engine in the cold. These devices preheat the engine block and its fluids to give you a smooth start and minimize the wear and tear of engine components. Using a block heater can save you from the frustration of failed cold starts. Fortunately, modern trucks equipped with the 6.7 Cummins engine get a block heater, which is useful for owners who live in regions with extremely cold weather. But where exactly is the 6.7 Cummins block heater located, and how can you use it safely?

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Finding the location of the 6.7 Cummins block heater requires a bit of exploration, but it’s manageable if you know where to look. Block heaters are preinstalled on all 6.7 Cummins engines, particularly in trucks like the RAM 2500 and 3500. To locate the heater, start by looking underneath the vehicle. You’ll find the heater on the passenger side of the engine, about two inches behind the oil filter and close to the exhaust manifold.

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In many models, the block heater is covered by a protective black cap that shields the heater connector points from dirt and debris. This cap will have to be removed to access the heater. While these heaters are offered on all 6.7 Cummins engines, heater cords might not always come with the truck, and you’ll have to purchase them separately. One of the top picks is this 120V Block Heater Cord, which is 6 feet long and has a high-temperature resistance.

If your vehicle does come with a heater cord, then you’re in luck. Depending on the vehicle model, the cord is found in different locations. For instance, if your RAM truck includes a heater cord, you’ll typically find it near the grille. The cord may also be bundled close to the engine block itself.

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An engine block heater is one of the simplest devices to operate. Once you have located the block heater and have either found or bought a heater cord, start by inspecting these two components for any signs of damage, such as typical wear or fraying. Since you’ll connect the cord to an extension cord, make sure to check that cord too. Ideally, the extension cord should be outdoor rated and heavy duty to handle the wattage of a block heater without damage. Engine block heaters have an average wattage of around 1,500 watts. Make sure the extension cord is completely unwound and long enough to reach the closest 120-volt outlet.

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There’s no need to leave the heater plugged in all night. Typically, your heater should be plugged in for two to four hours, allowing the engine to warm up before a cold start. Always unplug your engine block heater before starting your vehicle. Driving away without detaching the block heater could damage the cord or your truck.