How to Replace an Engine Block Heater

  • 2-4 hours
  • Intermediate
  • 45-100
What You'll Need
Replacement block heater
Car jack and stands
Drop light

An engine block heater makes up an important part of an efficient engine, which can cause the engine to fail if it develops a fault. Knowing how to replace the heater will enable you to maintain your engine properly and keep it in good working order.

Step 1 – Prepare

The first step necessary is to gain full access to the engine block heater from beneath the vehicle. Position a car jack beneath the framework of the vehicle and lift it sufficiently to allow you to work beneath, secure with jack stands. Lift the hood and prop it up securely before hanging a drop light to make it easier to see what you are doing. This step will allow you to switch off and unplug the heater, which you should do before undertaking any work.

Step 2 – Drain Coolant

Position a large capacity bucket beneath the vehicle and remove the drain plug from the bottom of the radiator to drain the coolant. This will make it easier to remove the engine block heater.

Step 3 – Remove Surrounding Components

You will find that there are two components known as expansion plates at either side of the engine block heater. These will need to be removed to give you access to the heater. It is prudent to take the opportunity to clean these at the same time.

Step 4 – Remove Heater

By feeling behind the block heater, you will be able to locate the hole that comprises the heating rod. This will enable you to check how the cable attaches to the heating rod so that you know how to reconnect it later. Disconnect the two components to leave the heater free. Use an Allen wrench to loosen the hex bolts that hold the engine block heater in place. Take care when you get to the stage of withdrawing them completely as you have to avoid dropping the washer beneath it. Once the fasteners are removed, you will be in a position to withdraw the block heater completely.

Step 5 – Assembly

Attach the plates to the new engine heater and apply sealant in accordance with the manufacturer’s instructions. Apply some grease to the opening of the hole that holds the heating rod as well as to the heating rod itself, avoiding the metal clip at the end. Install it within the engine and carefully secure the bolts in place, making sure that the washers are in the correct place. Reconnect the power cable to the heating rod and feel your way to the hole in order to insert the heating rod. Listen for the sound of a click which will signify that the rod has been properly inserted and is properly in place. Run the cable along the engine compartment until it reaches behind the grill to attach it to the cable ties. Refill engine and radiator with new coolant. Check for leaks. Switch it back on and test it to see if it heats.