Guide to the Engine Block Heater for Diesel Trucks
December 5, 2023

Guide to the Engine Block Heater for Diesel Trucks

Written By: ProSource Diesel

Most modern vehicles, including diesel vehicles, have been designed to operate in cold weather. This is mainly due to low-weight synthetic oils that start circulating faster.

However, freezing temperatures like you might find in Canada and the northern parts of the USA can still affect things under the hood like fluid and batteries. Too low of an outside temperature, and your vehicle might not start at all.

Diesel trucks have always been notoriously difficult to start in cold weather and usually, anything at or below 20 degrees Fahrenheit requires an engine block heater. Many modern diesel trucks come with a block heater from the factory, or they at least come with the heater element.

The dealership might try to sell you the cord for an exorbitant price, but you can easily get an engine block heater cord for an affordable price at ProSource Diesel.

Let’s take a closer look at the diesel block heater, how it works, and why you might need one.


Guide to the Engine Block Heater for Diesel Trucks

What Is An Engine Block Heater?

An engine block heater is a device that warms some areas of the engine when the vehicle is not running. Diesel engines are different from gasoline engines in that they don’t have spark plugs and require higher compression to start.

This also means they need higher temperatures to ignite fuel, which makes them more difficult to start in cold weather. An engine block heater heats things up so that the engine can start easily in cold temperatures.

What Does An Engine Block Heater Do?

The purpose of a block heater is to heat the engine block, but mainly the oil as cold oil tends to be thicker, which makes it hard for the engine to start. However, as mentioned above, low-weight synthetic oils don’t have this problem as much as heavier-weight traditional oil.

Nevertheless, using a block heater can help your engine turn over easier and get to operating temperature faster, which means you can put it under full load sooner without potentially stressing the engine.

How Does a Block Heater Work?

Modern diesel engines are generally equipped with glow plugs and air intake heaters which warm the combustion chamber and aid in cold weather starting situations. However, glow plugs do nothing to pre-heat engine oil, coolant, or other components.

Block heaters typically plug into a regular 110-volt outlet, and the heater then warms the engine block and important internal fluids like the engine oil and coolant.

Engine Block Heater Types

Most modern diesel trucks come with block heaters already installed, though as mentioned earlier, they may not come with the cord. Block heaters are also standard equipment on most vehicles sold in Canada. There are several types of engine block heaters, including:

– Engine-warming blanket

– Oil pan heater

– Dipstick heater

– In-line coolant heater

– Freeze plug heater

The typical diesel block heater consists of a heater coil or element and a block heater cord. These items can be bought separately, or they may come together in a block heater kit.


Guide to the Engine Block Heater for Diesel Trucks

When To Use a Block Heater On a Diesel Engine?

As you might expect, the most common time to use an engine block heater is in frigid weather. Most diesel manufacturers recommend that an engine block heater be used whenever you intend to start the engine in temperatures at or below 20 degrees Fahrenheit.

However, if your truck hasn’t been started in a while and it’s at least moderately cold, you might benefit from a block heater.

You should plug in your engine block heater roughly two to four hours before you intend to start your engine. Some block heaters come with timers so you can set it for a few hours before you leave in the morning. In theory, you could leave your block heater on for much longer than that as it doesn’t use much electricity, but you risk burning the heating element out faster.


Guide to the Engine Block Heater for Diesel Trucks

How To Install a Block Heater

  1. To start, you’ll need to jack up the front of the vehicle and secure it with jack stands, unless it’s a 4WD truck with good ground clearance.
  2. Open the hood and locate the block heater port. Remember, most modern diesel trucks come with block heaters, so you should have a block heater port.
  3. Put a pair of work gloves on and coat the heating element with thermal grease. Go heavy on the grease to make it easier for the element to go into the block port.
  4. Slide the element into the block until clicks into place.
  5. Connect the wiring by plugging it into the heating element.
  6. Route the cable away from the engine to an area such as below the grille or behind a fog light. It needs to be away from hot engine parts like the exhaust manifold and also away from anything that moves, like accessory belts. The outlet should also be easy to access from outside the vehicle.
  7. Secure the cable in place with zip ties and put the cap over the outlet to protect it.

As previously mentioned, you should plug in a block heater two to four hours before starting your engine.

If you need a block heater for your rig or you need to replace an OEM block heater, ProSource Diesel has you covered.

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