As winter tightens its icy grip, investing in an engine block heater can be a game-changer. If you live in a region where winter means sub-zero temperatures, many car owners find themselves faced with the challenge of starting their vehicles in freezing temperatures. In this guide, we’ll explore what an engine block heater is, its benefits, the different types available, and provide some tips on how to choose the best one for your car.
These are the engine heaters we recommend:
What Is an Engine Block Heater?
An engine block heater is a device designed to keep your vehicle’s engine warm during extremely cold weather. It consists of a heating element that is installed directly into the freeze plug of the engine block to heat the engine’s coolant or is attached to the oil pan to keep the engine oil warm.
When you warm your engine by heating the engine oil or coolant with an engine block heater, the warm engine oil will have a lower viscosity (thin/runny) than when cold, making it less sticky and easier for the engine to turn over and start on chilly mornings. This ensures a smoother start and prevents unnecessary wear on your engine.
An engine block heater works on all engine types, but has an extra advantage when used for diesel engines. Because a diesel engine needs heat to ignite the compressed fuel/air mixture in its cylinders, a preheated diesel engine won’t have the typical starting problems most diesel engines have in winter.
Different Types of Engine Block Heaters
While there are many different types of engine block heaters on the market, there are only three main types that work well:
Immersion Heaters
An immersion heater is immersed in the engine’s coolant by installing it in a core plug hole (aka freeze plug hole). It is mains powered and warms the coolant, which will in turn gradually heat the whole engine block, keeping it at a more favorable starting temperature. This type of heater is very efficient and widely used, especially in colder climates.
Magnetic Heaters
A magnetic engine heater is a removable mains-powered heating element that sticks to the outside of any steel oil pan with powerful magnets. It transfers heat to the engine oil in the oil pan. While they are the easiest engine heaters to install, they may not be as effective in extreme cold. You want to check your oil pan with a magnet first, because this type of heater does not work on non-magnetic oil pans (e.g.: aluminum)
Pad Heaters
A pad heater is an adhesive heating pad that is permanently attached to the engine block or oil pan. This type of heater can be used on any type of engine. It is easy to install and provides uniform heating. However, it might not be as powerful and effective as an immersion heater.
Things to consider when buying an engine block heater
Climate
Only if you live in a climate where winter temperatures often drop below freezing, you might want to consider installing an engine block heater. However, an engine block heater may be a very effective starting help for old diesel engines even when temperatures aren’t all that extreme.
Compatibility
Before ordering an engine block heater, you want to make sure the type and size of heater is compatible with your type of engine. While a stick-on heater fits all types of engines, there are different sizes available. Measure the available space on your oil pan or engine block before buying. For a magnetic heater, it is crucial to check that your oil pan is steel, not aluminum, or it won’t stick. An immersion type of heater is arguably the most picky type of heater. It needs to be the right type for your specific engine type or it will not fit or function properly. You want to check for compatibility first.
Ease of Use
Consider ease of use: You will need a mains wall outlet nearby and a suitable outdoor extension cord to power your engine heater. The heater must be easy to use on a daily basis: When installing the heater, make sure that the heater’s AC socket is installed within easy reach so you don’t have to crawl under your vehicle each time, to plug it in. Before buying a magnetic heater, make sure that you will be able to reach it without dislocating your shoulder.
When to Use
In normal winter conditions, it is not necessary to keep your engine block heater plugged in overnight. Studies show that efficient engine heaters warm an engine sufficiently within 2-4 hours. By using a timer that switches on 2-4 hours before startup, the engine should be warm enough to start it easily. By leaving it plugged in all night, you will most likely only heat the surrounding air and waste a lot of energy and money doing so. This rule of course does not apply for the most extreme climates up north.
Remember to Unplug
It’s of the utmost importance that you remember to unplug the heater before driving off. Some people use a bright colored extension cord and hang it across their windscreen or stick a post-it note on their steering wheel,… whatever works for you…
Ease of Installation
If you were born with a wrench in your hand, and you have a couple of hours to spare, you might want to install an immersed coolant heater. If you weren’t, and you want no hassle, consider a magnetic heater that is ready for use out-of-the-box and does not need to be installed. A stick-on engine heater is somewhere in between. Although it is self-adhesive, it needs a clean, preferably paintless surface to stick to. If you want it to last, you want to secure its contours with a seam of RTV kit too. Although you don’t need a master in automotive engineering to do this, you will need some elbow grease to install it.
Power Rating
Different heaters have varying power ratings. Choose a heater with sufficient wattage to effectively warm your engine, considering the severity of winter temperatures in your area. A heater with a higher power rating will heat your engine faster than one with a lower power rating. On the other hand, it may be more energy-efficient to heat your engine longer at a lower wattage so the heat has more time to spread throughout the entire engine block.
Fire Safety
In our selection, we were cautious to not select cheap types of unknown engine heaters that pose a real fire hazard. We recommend only using engine heaters from reputed brands. By paying a few bucks more you might prevent fire damage or worse.
Join Forces
If you live in an area with extreme cold, you might want to consider combining your engine heater(s) with a battery charger to keep the car battery from freezing and to have ample starting power when temperature plummets. For diesel engines, a fuel filter heater and a fuel tank heater might keep your diesel fuel from gelling.
How we did our review
Over the years we’ve tried and tested a lot of different engine block heaters for our cars. For this review we also dove deep in the manufacturer specifications and looked at loads of customer reviews to see what their experience was. Because not all types of engine block heaters are worth buying, we only selected three different types that really work. We only recommend heaters that did an excellent job for us and the vast majority of other car enthusiasts. We’ve selected engine block heaters for different applications, to make it easy for you to choose the right heater for your car, depending on your skill set and how much you expect to use it.
Check out our favorite engine block heaters:
Best Engine Block Immersion Heater
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Best Engine Block Immersion Heater
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- Type: Immersion
- Efficiency: High
- Ease of Use: Very Easy
- Ease of Installation: About 2 hours work and some skill required
The reason why we chose this engine block heater as our “Best Engine Block Immersion Heater” is because it is easy to use and very efficient, and probably the safest type of engine heater on the market.
This immersion engine block heater is available in different types to fit most vehicles. We found it very easy to pick the right type for our car. Installation takes a couple of hours, depending on your skills, vehicle and engine type, and you will need some medium-level mechanical skills to fit it in the designated core/freeze plug hole.
Once installed though, this heater is literally plug-and-play and it heats the engine’s coolant fast and reliably. You only need to plug its power cord into a mains extension cord and it starts heating. Most people plug it into a timer or a bluetooth switch to save energy.
Customers say that this is a solid Made-in-America product that is identical to the OEM part but at a better price. They say that all in all, installing this heater is a fairly easy DIY project.
PROS:
- Immersed engine coolant heating is the most efficient with the least heat loss
- Safest type of engine heater
- Sits well-protected on the inside of the engine
- Very easy to use; plug-and-play
CONS:
- Medium level mechanical skills needed for installation
- Takes about 2 hours to install
Best Stick-On Engine Heater Pad
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Best Stick-On Engine Heater Pad
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- Type: Self Adhesive
- Efficiency: Medium / High
- Ease of Use: Very Easy
- Ease of Installation: About 1 hour of work / only basic skills required
The reason why we chose this self adhesive car heater for our “Best Stick-On Engine Heater Pad” is because based on our experience and user reviews, this heater pad does what it’s supposed to with the best reliability track record.
Just like other self-adhesive heater pads, you need to clean and degrease the spot where you want to place the pad first. For optimal adherence, you can sand the spot to bare metal. If you want to leave it on permanently, it’s best to glue the sides of the pad to the surrounding metal using some RTV kit, so it can’t come loose over time.
Once it’s in place, this heater is also plug-and-play. Plug it in an outlet, and it starts to heat your oil pan right away.
Customers say that this simple device sticks well to any clean, degreased surface with its 3M tape and that it works as well as more expensive brands they’ve tried. Most people plug it into a timer or a bluetooth switch to save energy.
Based on the many customer reviews and our own research, this heater pad is arguably over three times more reliable than its (often more expensive) competitors.
PROS:
- Arguably the most reliable engine heating pad
- Fairly easy DIY installation
- Very easy to use; plug-and-play
CONS:
- Basic DIY skills needed for installation
- Takes up to 1 hour to install (depending on your skills)
Best Magnetic Engine Heater
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Best Magnetic Engine Heater
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- Type: Magnetic
- Efficiency: Medium
- Ease of Use: Easy
- Ease of Installation: Easy
The reason why we chose this multi-use magnetic heater for our “Best Magnetic Engine Heater” is because it is one of the most reliable magnetic engine heaters on the market today, yet affordable. It can be attached to anything metal with its powerful magnets. It provides heat where and when you need it: your car’s, truck’s, tractor’s or ATV’s oil pan or engine block, or even to your diesel generator.
The moment you plug it in an AC outlet, it starts heating. It even works great to keep metal watering tubs or gutters ice-free. Most people use a timer or a bluetooth switch to keep energy costs down.
With its quick-grip handle it can easily be placed and removed without burning your hand. The powerful magnets keep the heater firmly in place. This engine block heater has a built-in thermostat to safeguard it from overheating, it will not exceed 250˚F (121˚c). It’s weather-proof too.
You can stick it to whatever car, truck or equipment you’re going to need the following winter’s day, and you’ll have no trouble starting it.
Customers say they even use it to keep their satellite dish from getting snowed over in winter, it’s that versatile…
PROS:
- Versatility galore
- Does not have to be permanently installed
- Can be deployed with ease for varying vehicles or equipment, according to your priorities
- Built-in thermostat guards against overheating
CONS:
- Less efficient than an immersion or pad heater
Comparison Table of the Best Engine Block Heaters
| Brand | Name | |
|---|---|---|
| Best Engine Block Immersion Heater | Zerostart | Immersion Engine Block Heater |
| Best Stick-On Engine Heater Pad | APSG | Engine Block Heater Pan |
| Best Magnetic Engine Heater | Zerostart | Portable Electric Heat Magnet |
Final Thoughts
If you live where winter bites, you may need some help in the form of an engine heater to get your car, truck or equipment started when temperatures drop way below freezing. We dove deep into the engine heater market and surfaced with the three engine heaters that make most sense. They are all the most reliable in their kind yet affordable.
These are the engine heaters we recommend depending on what you are looking for, the time you want to put in installing your engine block heater and the skill set you possess:
If you live up north where eyelids freeze? You’re the type of person that has two right hands and you don’t mind spending a couple of hours installing your engine heater? Look no further: you want a permanent, professional OEM immersion engine coolant heater. It’s the most efficient engine heating solution, period.
Looking for a quick, no hassle solution? It has to be used for different cars, trucks or equipment? Slap on a magnetic engine heater and you’re done! No installing at all and it will heat anything metal it sticks to.
If you don’t feel confident enough to remove a core (freeze) plug and install an immersion heater in your engine block, but you want a permanent solution that is plug-and-play, a self-adhesive heater pad might be perfect for you.
It doesn’t matter which of these three solutions you choose, they are all hot (pun intended). Gone are those awful will-it-start winter mornings. You can now leisurely finish your hot coffee with a yawn and start your vehicle with confidence, no matter how cold it is outside!
Happy (winter-) cruisin’!
Stay safe!
FAQ’s
What does an engine block heater do?
When you warm your engine by heating the engine oil or coolant with an engine block heater, the warm engine oil will have a lower viscosity (thin/runny) than when cold, making it less sticky and easier for the engine to turn over and start on chilly mornings. This ensures a smoother start and prevents unnecessary wear on your engine.
When to use an engine block heater?
If you live in a climate where winter temperatures often drop below freezing, you might want to consider installing an engine block heater. However, an engine block heater may be a very effective starting help for old diesel engines even when temperatures aren’t all that extreme.
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