During extreme temperatures of not above -20° C r, oil thickens up and becomes unable to move throughout the diesel engine. The engine has to work harder and use more gas. You can only avoid this by using a block heater. Let’s explain how long you can leave your 7.3 plugged in.
Always have the block heater plugged in your 7.3 for about two to three hours to drive off quickly in extreme coldness. Avoid plugging in the heater overnight to save on the energy bill. You’re likely to have difficulty starting your engine on a cold morning if you don’t plug it in.
The temperature when plugging in your engine block heater varies. However, consider it when expecting the night or morning to be freezing. Newer cars can start at temperatures below -30° C, but it strains the engine if you don’t plug in your block heater.
The rule of thumb is to plug in your engine if the temperatures are about -15° C or lower. For a diesel engine, you must plug in your block heater before temperatures become this low. Various factors determine how long to leave your engine plugged in.
How Long Can You Leave Your 7.3 Plugged In?
You must plug in the block heater for about two to three hours for a clean and easy start. It’s enough time to get the coolant heated up and the icy chill of the oil. It thins out to some degree for the injectors to fire more easily.
The block heater can remain plugged in for about four hours if it’s super cold. Beyond that would be wasting money. A regular 7.3 block heater uses 1000 watts of energy which adds up depending on how long you keep it plugged in.
A cheaper way to ensure that the heater runs for the necessary time is by using a plug-time switch. You can set it to start working for a given period before your intended moment to drive away. It saves a significant amount in power bills compared to leaving it plugged in all night.
Can I start the car with the block heater plugged in?
Never start your car with the block heater plugged in to avoid damaging the heating element. This is because before starting the car, the element has heated the coolant around it, leading to stabilized temperature.
On starting the engine, it sends colder coolant, flushing it directly on the element. The sudden temperature change may damage the element. Unplugging the block heater before starting the car I strongly recommended.
How Do I Tell The Block Heater Is Working?
If you plugged in the block heater for the recommended hours, but your car doesn’t start, you must check whether the device works. Here are some ideas to confirm.
Check Coolant Temperature
Your car may display coolant temperature depending on its year of make. If the temperature is high, it shows that the block heater works. Note the coolant temperature when plugging in the block heater. Recheck the temperature after 30 minutes to see if there’s an increase.
Feel the Engine Block
Physically feeling the engine block allows one to determine whether the block heater works. You plug in the block heater and wait between 30 minutes to an hour to feel the engine block. Afterward, feel another part of the car, such as the bumper.
The block heater works if you detect a noticeable temperature difference.
Listen For a Hissing Sound
You can also tell whether the block heater works if you hear a hissing sound from your diesel engine. Just plug in the heater and listen. When you hear the sound, rest assured that the block heater is doing its job.
Start Your Engine
If you plug in your block heater for about two to three hours, start your engine to see if it starts. The engine would start effortlessly if the heater did its job.
What If the Block Heater Works, But the Car Won’t Start?
Check the glow plug system and the injectors if you confirm that the block heater works but your car won’t start. First, check the engine glow plug relay using a screwdriver and jump the two terminals on the relay for about 30 seconds with the key on.
When the car fails to start, check other components such as:
- Glow plug
- Wiring
- Harnesses
- Injectors
- Injector control module.
What Happens if I leave the block heater Plugged in overnight?
Plugging in the block heater won’t damage your engine but will waste energy. Use a timer to ensure the heater draws power for a given period to avoid a high energy bill. About two to three hours is enough to make your diesel engine start on a cold morning.
Does A Block Heater Heat Oil Or Coolant?
The block heater heats the engine block. However, it directly heats the coolant but not the oil. However, the oil and other components heat to the extent that is not significant.
Final Thoughts
Starting your diesel engine on a cold morning may be tricky if you don’t plug in the block heater. Ensure to plug in the device for two to three hours for your engine to start quickly. Don’t let the heater remain plugged in overnight to save power.
