Why Does Diesel Have a Hard Time Starting in The Cold?

Starting diesel engines during cold weather can be frustrating if engines are not properly prepared for low temperature. And this alters battery capacity as well. Weak batteries may not crank the starter motor long enough or fast enough to push the cold engine to start.

Cold weather, especially extreme cold weather, causes havoc with the diesel engine ignition system. There’s a myth that diesel doesn’t burn, diesel does burn-one of the major difference between diesel and petrol is the way the two fuel burns. Petrol vaporizes much faster than diesel, this causes the explosive effect when it is ignited. Diesel doesn’t combust as easily as petrol does so it burn slowly.

Glow plugs

Glow plugs play a vital role during the first part of the ignition process. It can be difficult to start a diesel engine at low temperatures because then the engine cylinder needs to be warm for the fuel-air mix to ignite spontaneously when compressed. However, there is glow plugs in a diesel engine which warm the cylinders before you start the engine. A modern engine will power the glow plugs for the correct amount of time given the conditions before starting, an older engine will use few minutes each time the ignition is switched on.

Glow plugs are like spark plugs, but instead of igniting a fuel-air mixture, they warm the inside of the cylinder during startup. In case of diesel external heat source is required, that is conducted by a dense metal of cylinders and pistons which helps in spontaneous combustion of a compressed and heated fuel-air mixture.

The purpose of glow plugs is to provide high temperature so that when atomized fuel come in its contact, ignition will occur.

The entire block is colder in cold weather, however, part of the block conducts the heat from the cylinders that the glow plugs provided, therefore they are not effective.

Many diesel cars have glow plugs that are activated during cold weather before the start (which is seen as a yellow spiral symbol light on the dashboard).

Need to Do

Before you face the issue during cold, do take care of a few things:

  1. For cold weather start, use glow plugs or block heaters.
  2. To eliminate the potential problem do check your car battery, replace it if it is weak or suspicious. If it needs a battery replacement, be careful of replacing with the battery equal to or more powerful to the original one.

Avoid uses of the heater, air conditioners, radios, and other high amperage devices which put extra strain on batteries. Turn them off while using starter motor during car start.


Diesel fuel has a waxy substance in it. When it gets cold, these start to solidify and catch in filters and injectors. They block the flow of fuel sometime which may create a problem in starting an engine. Water finds its way into diesel fuel too, they may clog the filter as it turns to ice during cold. The high flammability limit of oil is maintained by a diesel engine.

Driving a diesel in very cold temperature can result in the fuel gelling. Once fuel gels, the engine will stop running and we have to get the vehicle warmed up again inside a heated building before it will run again. It’s not necessary that engine is only responsible for no start, fuel also takes part.

Fix It Up!!

To enable fuel to burn faster and cleaner we can use a combustion catalyst called FTC Decarbonizer.

At start-up, the active component in the FTC Decarbonizer ignites the fuel, which in turn catalyzes the fuel burn, which results in faster cold starts.

Typically, deposits build up in several critical regions: Injector tips, Cylinder glaze, Piston ring deposits, Combustion and Exhaust deposits.

Rather than carrying out expensive mechanical work to physically remove, clean and replace affected parts, engines, and fuel systems. All these can be removed by safe chemical means and with minimal downtime. In fact, much of the cleanup occurs during actual, normal driving.

Key items to be aware of!!

Check the Engine Block Heater – Always make sure the block heater is plugged into shore power and in functional condition. This heat source is very much helpful in starting issues. If your generator does not have a block heater and you are in a susceptible area for cold weather, then you should look into adding one. Keep Checking fuel – Always confirm that fuel in a tank should be treated with anti-gel and anti-microbial additives

Check the Exhaust and Ventilation – Make sure proper attachments and a visual inspection are done periodically. To reduce the amount of snow entry we can add a generator with a snow hood. Understand that shutters can also affect how cold air enters the system during startup. Hydraulic ones are often best for colder climates, so you don’t inadvertently shock the system with a bunch of freezing air during startup.

Keep checking your Digital Control Panel – During severe cold, these also get affected by the cold. Some of these will simply not even turns on and light up and/or you won’t be able to read the gauges. However, in the new model, all these issues are reduced enough but it might happen occasionally.

Points to keep in mind in extreme cold

Try to park the car in close space like garages, barns or sheds. Even you can park the car facing a wall, as this also prevent the cold wind from entering the car engine.

Carry a piece of fur or thick blankets in the car, while parking closes the front grill and other openings into the engine bay. This will prevent heat from escaping to outside. Wait until the glow plug heats the engine cylinders before cranking the engine.

Can Resolve

Proper engine operating temperatures assure more efficient fuel combustion and may prevent damage to cold engine parts.

Can add an additive in diesel in cold areas, the additive is used to lower the auto-ignition temperature, while maintaining or increasing the cetane value. Cetane value gives a measure of how soon a fuel combust. In cold days, allow the engine to warm up for some time as you start the car engine.

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