Freeze-ups and gelling in diesel engines is a common problem in the winter months. At Wheelco, we do everything we can for you to keep your truck running smoothly, no matter how cold the temps may drop. That’s why we have many solutions to meet your cold weather needs, like silicone heater pads, oil pan warmers, FPPF cold weather chemicals, etc.
One of the most effective way to heat your diesel engine is through the use of electric immersion heaters. We’ll explain how they work, different types, and tips for saving money.
How Immersion Heaters Work
An immersion heater is an electric heating element, commonly copper, that is positioned in a diesel engine block to heat the liquid within it. A strong electric current is passed through the immersion heater, using AC power. The heat generated is distributed throughout the engine. **IMPORTANT TIP***ALWAYS UNPLUG IMMERSION STYLE HEATER BEFORE STARTING. Most of the time a heater will create a kind of “flow” moving the fluid in a certain direction. As a truck starts, sometimes the water pump may send the fluid a different direction which can cause air pockets to move past the hot element, and in an instance, burn in out.
How Thermostats Work with Immersion Heaters
The thermostat measures the temperature and regulates the engine block heater by cycling the heater on and off. This keeps the convection flow keeps the fluid in the engine at consistent temperatures.
Wheelco Quick Tip for Saving Money: Phillips & Temro report that block heaters take up to 1500W of power per hour. This wastes energy and your money on warmer days. We recommend adding a Zerostart / Temro thermostat to help maintain the operative temperature in your vehicle’s engine. The bi-metal switch naturally opens so electricity does not flow when the designated temperature is reached. When the discs touch electricity can flow again.
Types of Immersion Heaters
There are 4 common types of immersion heaters. All are used to provide direct heat to the engine coolant. They are used to help ensure quick starts in the winter or during cold temps. Want the highest rated? Need the most efficient so you can stay on the road, no matter what winter throws at you? At Wheelco, we understand that when your truck is down, it costs you time and money. That’s why we recommend using Phillips & Temro immersion heaters. They are proven to be the highest rated and most efficient type of heater. While these immersion heaters are OEM factory installed in many applications, there are different types that are manufactured to fit your specific needs.
Freeze Plug (V-Lock) Immersion Heater
The freeze plug immersion heater fits directly into a frost plug port. It has a copper heating element and V-LOC locking system.
Features
- Plated stamped steel and forged brass adapter
- Copper heating element for maximum life and efficiency
- V-LOC locking system provides a quick, secure installation

Threaded Immersion Heater
The threaded immersion heater should be installed directly into the engine block.
Features
- Plated steel
- Copper element for heat transfer

Plate/Bolt-On Style Immersion Heater
The plate or bolt-on immersion heater mounts directly to the engine block.
Features
- Plated steel adapter and plate
- Copper heating element maximizes heat transfer

Cartridge Immersion Heater
The cartridge immersion heater is placed directly into a dry cavity of the engine block.
Features
- Quick installation
- No need to drain engine coolant

Benefits of Immersion Heaters
- Ensure quick winter starts
- Reduce engine wear
- Engine coolant heater
- OEM factory installed in many applications
- Plated steel adapter
- Replacement cord sets available
Popular Industry Types that Use Immersion Heaters
- Light Duty Truck
- Heavy Duty Truck
- Agricultural
- Industrial
- Construction
- Mining
- Forestry
Be Prepared for Cold Winter Temps
We carry an assortment of Phillips & Temro immersion heaters for many applications – Caterpillar, Cummins, Mack, Navistar, Detroit Series, and more. Stop in or call one of our many locations, or shoot us an email and our experts will find the immersion heater for your specific needs.