Starting Car Engines in Extreme Cold

The good news is your automobile was designed to operate in cold climates. The bad news is subzero temperatures for extended periods of time can cause problems requiring emergency repairs. When it comes to starting car engines in extreme cold the two major factors to consider is the power available in the battery to crank the engine and the thickening of engine oil.

In other words, the oil thickens making it more difficult to turn the engine over while at the same time, the cold works on the battery reducing the available cranking amps, diminishing the strength of the starter motor. In this article we’ll talk about the effects of cold on car engines and some ingenious aftermarket solutions for those living in Arctic climates.

Engine Cranks Slow Cold

It is normal for an engine to crank slower in subzero temperatures than it would on a 70 degree day. Generally speaking, batteries do not work well below freezing. This is because the power generated is a chemical reaction affected by the outside temperature. In fact, the battery only produces about 40 percent of its total power at zero Fahrenheit. When you throw in the thicker oil and the increased demand on the starter to spin the engine, slow cranking is the result.

People get nervous because in this situation, it sounds like its struggling. One of the major participating factors of how slow the engine rotates is the available cold cranking amps from the battery. Technically speaking, this is a rating that indicates the amount of amps that a fully charged battery will be able to supply and maintain for thirty seconds without the terminal voltage falling below 7 V.

Cold cranking amps (CCA) is indicated on the battery label and is usually between 300 and 600 CCA. Four-cylinder engines that require less power will be towards the lower end of the scale whereas V8 or diesel engines with high compression will be at the top of the scale. It is important to remain within the manufacturer specifications when replacing a battery.

Coolant Protection Level

The problem with having water circulate in the cooling system is it expands when it freezes. Engines are designed to handle the situation with the installation of freeze plugs that are pushed out and provide room for expansion. When this happens the engine may be saved, but repairs will be required before the vehicle is road ready.

The number one line of defense against this unwanted scenario is properly protected antifreeze. The tool used to verify the freezing point of engine coolant is called a hydrometer. It provides an accurate indication of the current protection level. Most factory mixes of antifreeze provide protection to -35 degrees Fahrenheit. Motorists should remember that this is the static temperature and not the wind chill.

Engine Block Heater

The block refers to the lower section of the engine that houses the cylinders, pistons, crankshaft and other related parts. It also contains a generous amount of the engine’s total coolant. A block heater will often replace one of the freeze plugs and contains a heater element that can be plugged into standard household electricity.

Since metal is a good conductor of heat the element does a nice job of transferring the produced heat throughout the entire cooling system. Although its primary function is to eliminate the chances of engine damage due to the expansion of freezing coolant, two nice side benefits is enhanced starting capabilities and quicker availability of heat to the interior cabin even in the most brutal temperatures.

Solutions for Cold Engine Starting

An engine won’t start unless it is cranking fast enough to produce compression for combustion. As outlined in this article the two major factors slowing the engine rotation down in freezing temperatures is the thickness of the oil and the reduced power from the battery. Aftermarket solutions abound for addressing both of these issues.

Although factory block heaters often use freeze plug type elements aftermarket suppliers have come up with some different solutions. One of these is a magnetic heater that can be placed on metal engine blocks or an oil pan. When placed on the pan the heater directly warms the engine oil. Magnetic heaters can also be used around the house to thaw gutters and well pumps. Since magnets will not stick to aluminum, it’s not suitable for all engines.

For those with aluminum engines they make special lower radiator hose heating systems that are straightforward to install and plug directly into household outlets. The final solution for cold starting engines is a thermal battery wrap. This is a miniature heat blanket that plugs right into household AC power and is designed to wrap around and warm car batteries, raising the available power for cranking cold engines.

In conclusion, aftermarket solutions are available that can make your automobile feel like it’s at the beach, even on the coldest days. In environments that experience subzero temperatures for long periods of time additional freeze protection can be achieved by draining out some coolant and replacing it with straight antifreeze. When summer returns drivers should drain the system and refill with a 50-50 mixture as recommended by the manufacturer. Failure to do so can cause engine overheating situations as antifreeze does not have the same heat exchanging qualities as water.