Tips for Improving Your Diesel’s Cold Starts

truck in winter


It’s no secret that diesels can be hard to start when the temperatures drop. Here are a few tips to help make sure your truck starts when you need it to:
  • Block Heater – It’s hard to find a diesel truck without one of these installed, but almost everyone has forgotten to plug their truck in overnight at least once. To save time and electricity, consider putting the block heater on an electrical timer so it automatically turns on a couple of hours before you plan to start the engine.
  • Diesel Winter Anti-Gel – Diesel fuel contains wax paraffins, which start to solidify when the temperature drops. Depending on each individual fuel station and type of diesel fuel, typically at 32 degrees, the wax in the fuel will crystallize and leave the fuel tank clouded. At 10-18 degrees, the paraffins can start to gel and clog the tank and fuel filters. Hot Shot’s Secret Diesel Winter Anti-Gel reduces the pour point of fuel to -65 degrees and prevents diesel fuel gelling in #1, #2, and blends of Biodiesel up to B20.
  • Check the Owner’s Manual – Many manufacturers will have a specific set of instructions for your engine in the event of severe cold weather. Whether it tells you to cycle the manifold heater 2-3 times, or that the transmission shift range will be changed or maybe you’re not familiar with the low traction system, the owner’s manual is worth referring to.
  • Maintenance – If you’re having issues in cold weather, check FICM voltage, inspect glow plug relay and wiring, and have your battery/batteries tested. You can also prevent issues by replacing your fuel filter as recommended in the owner’s manual, making the switch to a quality synthetic engine oil and keeping your fuel and oil system clean and protected with Stiction Eliminator every third oil change and Diesel Extreme every 6 months.
  • Battery – If you can tell your truck is going to be difficult to start just by looking outside, or your batteries are getting close to their life expectancy, or you know you’re truck will sit outside in the elements for an extended period of time, pulling the battery and storing it in a temperature controlled setting to warm it up is a great idea. This sounds like a hassle, but if you need to jump start a battery that’s been sitting in sub zero temperatures you run the risk of cracking or even exploding the battery! Next time you shop for batteries check out the warranty periods and ask which ones offer free replacement.
  • After Start Up – Allowing the engine to warm up a few minutes before putting the engine under load is a great habit. Proper operating temperature provides optimal fuel combustion and may prevent damage to engine parts, especially if you’re hauling or towing. Not to mention the engine oil will flow more readily when it’s warmed up providing protection to the rest of the engine.

4 thoughts on “Tips for Improving Your Diesel’s Cold Starts”

  • I HAVE AN AUDI Q7 DEISEL 80,000 MILES AND GOOD SERVICE HISTORY.

    IT HAS JUST STARTED TO TAKE A LOT OF TURNS TO START THE BEAST THESE SUMMER MORNINGS. ONCE STARTED ITS PERFECT.
    SOMETIMES ITS JUST STARTS AS SOON AS THE HEATER LIGHTS GO OUT.
    ANY ADVICE PLEASE

    ROCK AND ROLL

    • A common root cause for your hard starting problem on the 3.0 TDI is a valve in the fuel system. This valve can become slightly gummed up and cause the fuel to slowly leak back into the return line which reduces the fuel pressure on your cold starts. It also helps explain why after it’s started, it will continue to start all day, but once it sits for more than say 10 hours, you experience the hard starting. We’d recommend Diesel Extreme to help clean the fuel system.

  • Block heater is great on my 1985 Mercedes, but that doesn’t help at work since there is no where to plug it in.

  • Speaking from personal experience, it is so important to have a block heater ready just in case. I was once stuck out in a blizzard in the middle of nowhere, but was able to get on the road because of that little heater. Great article, I’m sure someone will need it like I did out in the cold!

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