In order to successfully install an HLN diesel coolant heater to avoid engine cold-start, the following key points should be noted. 

1. The heater should be installed at the lowest point in the coolant loop, so coolant can flow freely into the water pump. Water pumps excel at pushing fluid upward but are inefficient at drawing fluid from below.

2. The heater should be mounted at a stable location to avoid excessive vibrations.

3. The exhaust pipe operates at very high temperatures and must be kept away from all heat-sensitive materials.

4. The mounting holes of the 5K unit are self-tapping, and self-tapping bolts are included.

5. The coolant heaters should be mounted with exhaust port facing down toward the ground.

6. The coolant loop of the 5K unit should be shorter than 10ft; the 10K unit can allow up to 30ft.

7. Fuel pump should be tilted slightly upwards, at about 30 degrees.

8. Fuel pump should be within 3 ft from the fuel tank, and it can draw fuel up to 3 ft.

9. At first start after installation, as there is no fuel in the fuel line, the controller may display an E13 combustion error code. This is normal, and just start the heater a few more times until the fuel comes up from the tank and reaches the heater.

10. Only errors displayed on the main screen indicate active heater malfunctions. The error code shown in the 'Error' section of the controller only records the last error that occurred.

That’s it. Enjoy our coolant heaters!