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Car won’t start? Do you need Engine Block heater, How it works, How long to plug in, Is it working?

Blog_Cars_Car won't start. Do you need Engine Block heater, How it works, How long to plug in, Is it working

If you don’t know what a block heater is and you live in the winter zones where temperatures fall below -10 degrees Celsius then it would be good to learn the benefits of using a block heater.  From helping your car start in the extreme cold to protecting your car, a block heater is a relatively inexpensive tool.  Start by watching our video to finding out what a block heater is, what it does and how long to plug it in for.  Discover how you wear out your engine and starter prematurely by cold starting your vehicle.

On the other hand, if you know what a block heater is and need to get one installed on your car, find out why it should not cost a lot to get installed (some people pay the dealership a lot of money to get one put in when they buy a new or used car).

Then lastly, it’s very important to know if the block heater is working or not.  Learn two ways to test your block heater in our video.

 Find links below to purchase the block heater testers and other related products.

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Whether you use regular motor oil or synthetic motor oil, you can protect your vehicle and the money you put into it already by using a #blockheater in the winter time when the temperature falls below 0°C.  This is a winter time essential and a polar vortex/climate change Must!

Let’s get started!

For those of us that live in the colder winter zones, minus 20 and below temperatures are a seasonal norm.  Whether you own a car or use someone else’s, having it start reliably in the winter is important.  One way to ensure your car starts when it’s really cold out is to use a Block Heater.  Here are the top 4 questions people ask about Block heaters:

  1. What are block heaters and how do they work?
  2. Are block heaters needed?
  3. Should I get a block heater installed at the dealership when I buy a new or used car?
  4. How do you know if the block heater is working or not?

Read on as I delve into these questions and also reveal why you might be overpaying to get this installed at the dealership.

Before we get started…

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What is a Block Heater?

Let’s start by quickly going over what a block heater is.  You basically have 2 components.  A heating element that is installed in a port of the engine block and … a block heater cord.  The heating element heats the coolant in the engine and the cord supplies the power.  One end plugs into the heating element and the other to an electrical outlet.  That’s it.

Some people end up paying $500 or more for the dealership to install a block heater.  What they didn’t know is that usually all the mechanic may be doing is simply plugging in the block heater cord.  Keep reading as I will show you later in the video how you can avoid this by learning from my actual experience with a dealership.

Are Block Heaters Needed?

Now that we know what a block heater is, let’s find out why you might want one.

First, the most obvious reason is to have your car reliably start when it gets too cold out.  When cold out the engine oil becomes more viscous, like taffy or thick honey, and the battery will supply less current.  Plus, on initial startup, the oil can’t lubricate the critical components properly.  Combine those two factors and your vehicle will have a harder time starting.

The second reason is to prevent wear and tear on your engine and starting system.  Cold starts cause the most wear and tear on these systems.  When you have -15°C or lower temperatures the oil will be more viscous and therefore the oil pump will have a harder time supplying enough oil to lubricate all the internal components of the engine.  Plus, the metal parts within the engine are not at their ideal tolerances for operation when cold (remember that metal contracts when cold, expands when hot).  Although using synthetic oils will help, the metal still needs time to heat up and this is where the block heater can help.

In very cold temperature, the oil actually takes several minutes to get above 0°C.  I would definitely recommend a block heater if you choose to use regular motor oil.  Regular motor oil more easily becomes taffy like when temperatures drop.  Block heaters are also good for Diesel vehicles as they are more easily affected by cold temperatures.  And for temperatures below -15°C, I would definitely recommend it even if you use synthetic oil.

Third, if you use a block heater a few hours before you need the car, your engine block will be warm by the time you need it and you will get heat sooner from the heating/HVAC system.  You only need to use it between 1 to 4 hours before you need your car.  Of course, the length of time would depend on the temperature outside.  Ideally you can just use a timer so that it turns itself on in the morning at a pre-set time.


  • Some vehicles have a thermostat on the block heater system that prevents the block heater from running until a certain temperature is reached.  For example, some GM vehicles have a sensor in the plug cord that doesn’t let the block heater turn on until it is below -18°C.
  • Some public plug outlets (like at apartment complexes) have plug outlets that are timered.  They have a set schedule for when the plugs are energized with power.  In this case, you will need to find out what the schedule is.

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Where Should I get a Block Heater Installed?

Did you know that most cars sold in colder climates already come with a block heater element pre-installed at the factory?

Even though this is the case, dealership salesmen still try to get you to pay several hundred dollars to get it installed by their service department.  When I bought my Mercedes-Benz C-Class at the dealership, they tried to offer it as a Dealer Option installed for ONLY $500.

Expensive charge for a block heater to be installed at the dealership as Dealer Option
Expensive charge for a block heater to be installed at the dealership as Dealer Option
Block Heater cord plugged into block heater element in engine bay
Block Heater cord plugged into block heater element in engine bay

You might get caught in a similar situation but there is a quick and easy way for you to find out!

Call the dealerships Parts department.  That’s what I did and found out the car I was interested in came with a block heater pre-installed at the factory and all that was needed was a block heater cord to be plugged in or installed.

I later bought one from the parts department, brought it to my mechanic and had it installed in under 1 hour.  I paid $66 CAD for the block heater cord plus labour and taxes.  Note that you can get most block heater cords from $40 to about $70 depending on the make and model of vehicle.

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Is my Block Heater Working?

Now that we know so much about block heaters, how do we know if our block heater is working?  Let’s do a quick check to make sure our block heater is functioning properly.

First: check that the cord is in good condition and not frayed or damaged.  Damaged cords need to be replaced.

Next, the best thing to do is to buy a block heater tester or energy meter.  Some people plug in a night light to test things out but that doesn’t test the block heater.  Same goes for an extension cord that lights up at the end.  These only tests the outlet and the extension cord connected to it to let you know that power is available in the extension cord.

You need a special tester that will tell you 2 things.

  1. if the outlet has power, and
  2. if the block heater is drawing any power from the outlet

That is what these two devices do.

Alternatively: Just plug in the block heater then wait and listen.  You will start to hear a sound similar to what an electric kettle makes.  It pretty much sounds like liquid starting to boil and sometimes some pinging as the metal in the engine block starts to expand.

Listening in the engine bay to hear if block heater is working or not. Block heater sounds like an electric kettle when on
Listening in the engine bay to hear if block heater is working or not. Block heater sounds like an electric kettle when on

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And there you have it.  All you need to know about Engine Block heaters.

Here’s a bonus for reading to the end of our post … If you don’t have a block heater but need to heat up your engine because your car won’t start, you can use one of these magnetic or silicone pad heaters (Shown above).  These work good and can be attached to the oil pan, intake manifold, or engine block of your car.  You can even use this on Snow blowers, chainsaws, snowmobiles and other small engines and pipes that need heating.  There are different sizes and Wattages available so pick one that suits your needs

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