DIESEL COLD START 101

Have you noticed on cold days that your diesel may be a bit sluggish starting up? Like many of us, we get a little grumpy during the cold months. Our diesels are the same way, they sputter and have a hard time turning over in the cold. These below freezing temperatures wreak havoc on diesel engines. We can’t control the weather, but we can control how to help our diesels from having the winter blues. Even if you live in warmer climates, there are some things to consider to keep your truck’s engine looking good and running at its best.

First, let’s understand the basics of what the cold does to a diesel. Think about oil that is below freezing and is as thick as molasses. Well, maybe not that thick, but you get the idea. The colder the oil is, the harder it is to move. Then you start your engine and it spins up to idle which is around 800-1000 RPM. The oil is supposed to flow to all the moving parts in your engine to keep any metal to metal contact from happening. However, when the oil is cold it does not flow as fast so there are a few seconds that these spinning and moving parts may not get oil like they should.

First, let’s understand the basics of what the cold does to a diesel. Think about oil that is below freezing and is as thick as molasses. Well, maybe not that thick, but you get the idea. The colder the oil is, the harder it is to move. Then you start your engine and it spins up to idle which is around 800-1000 RPM. The oil is supposed to flow to all the moving parts in your engine to keep any metal to metal contact from happening. However, when the oil is cold it does not flow as fast so there are a few seconds that these spinning and moving parts may not get oil like they should.

Diesel fuel also can gel in the cold. This means that the paraffin wax present in diesel fuel starts to solidify when the temperatures drop. This can leave the fuel tank clouded. When the temperature drops to 15 degrees Fahrenheit or less, it will gel more and actually clog the fuel filter.

The other issue is getting a diesel to start when its cold. Why is this an issue you may wonder? Well, a diesel does not use anything to ignite the fuel in the combustion chamber. The fuel is ignited when there is enough heat from the pressure of the piston compressing the air and then when the fuel is injected it needs to be hot enough to immediately ignite. Newer diesel engines are using a common rail fuel injections system which injects fuel and a much higher pressure and with computer controls that are more precise then the older mechanical engines. This makes the new diesel engines easier to start when it gets cold.

So how can you help your beloved diesel during these cold months? Here are three tips to help your diesel battle the cold.

Fuel additives help for easy fire-up of your vehicle. These additives help the diesel fuel not go into the “gelling” state, but keep things moving so it can lubricate the injectors and other critical components. Additives also prevent and clean any deposit buildup, protect against corrosion and improve the gas mileage. You can use an additive every time you fuel up. The best part is that these additives can be used throughout the year for maximum performance.

Many gas stations offer winterized diesel fuel during the cold months. It’s a specialized winter blend of fuel mixing number 2 diesel with number 1 kerosene. It tends to make the fuel thinner and has a de-icer chemistry that helps prevent plugging the fuel filter. So look for one in your area that offers this. It’s typically less expensive to go this route instead of mixing fuel yourself.

A simple and effective option for keeping your diesel warm is to look for the plug in the front of your truck and then test it to make sure it works. Many people forget that they have this option. If you live in cold climates and don’t have this, you may want to look into it, especially if you can’t park in a garage. Ensuring that you have a warm truck helps with it cranking over. You can plug in your truck before heading to bed on those particularly cold nights. When you wake up and are ready to go, the engine will be warmer and ready to start. Be sure to let your diesel idle for a while on those cold days so it can warm up properly and be ready to roll.