Block Heater

Introduction
Block heaters slowly pre-warm the engine before starting with a 200 to 600 watt 110volt heating element that is directly installed into the engine block. The reduced warm-up time can dramatically improve fuel economy, especially for short trips. It is recommended to put the heater on a timer that starts to heat the engine no more than about 3 hours before departure to avoid wasting electricity. The ultimate way to warm the engine faster and use less electrical power is to use the biggest block heater you can get your hands on, if one isn't enough use two. With multiple high wattage block heaters it becomes possible to warm the engine up faster and by default disbursing less heat into the surrounding environment. This cuts warm up times down to well under an hour.
Use immersion heaters that come in direct contact with engine coolant for best result. Only use stick on heaters as a last resort.
Not to be confused with high power coolant warmers, these usually require forced circulation and are fuel burning, 110 or 220 volt powered.

Instructions for mod

Refer to workshop manual and installation instructions for block heaters for installation methods

See how to's for some car specific instructions in the references at the bottom of this page.
The block heater shown to the right is a Kat's universal 400 watt block heater. It has 3/4 inch male pipe threads making it able to thread into lots of places.

User experiences

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User data
User Name	Car Make, Model, Year	Cost of Mod	Time to Perform Mod	MPG Before Mod	MPG After Mod	MPG improvement guess	Instruction Link
Doax	Toyota, matrix, 2003	~$60 USD	~ 1.5 Hours			~4% (During winter less than 2MPG) no hard data just rough estimation.	Metro block heater install (not Doax's install)
TomO	1994 Honda Civc VX	$45 USD	< 1 Hours	43.12	44.93	4.2% (1.81 MPG) tank to tank data, but consistent route and driving	VX block heater install
Echo-Francis	Toyota Echo 2005	$50	2 Hours			Not tested. My engine defenitely start well when cold, i'm saving.	Echo-Francis Block Heater
Oil Pan 4	Chevy suburban diesel 84	$100 USD	3.5 Hours			FE effect untested. Was able to raise coolant temperature from -2'C to 22'C in 15 minutes with out running the engine	3500 watt universal fit coolant heater

Problems / Consequences of mod

- User of electricity to heat car before traveling may outweigh the environmental and financial savings of modification
- Idle reduction
- Enter the much more efficient closed loop mode sooner.
- Remove frost so you can see, avoid crashing into objects.