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2010 VW Jetta TDI Cup Edition: Cold Weather Start – Click above to watch video after the jump

The 2.0-liter turbo diesel in our long-term 2010 Volkswagen Jetta TDI Cup Edition is a very modern mill, so we were curious how it would handle starting in the frigid clime of northeastern Ohio this time of year.

Diesel engines typically have three vulnerabilities when it comes to cold weather starts: the fuel, the battery and their glow plugs. First, the new Ultra Low Sulfur diesel fuel we all use begins to gel at a higher temperature than the old fuel. Sulfur is also a lubricant, and with less of it, the fuel pump has to work harder in cold temperatures to keep the thicker diesel fuel flowing. Fortunately, most diesel fuel sold in colder areas has ant-gelling additives mixed in already.

Batteries are also less efficient when cold, while at the same time having to work much harder to crank the engine more times. Finally, diesel engines use glow plugs to heat the point of combustion in each cylinder, which is a much tougher job when the mercury drops below freezing. Optional block heaters can help a diesel engine start in cold weather, but Volkswagen has enough faith in its 2.0-liter TDI that it doesn't even offer one.

So how did our Jetta TDI Cup Edition do when being started in 25-degree weather after sitting for over 24 hours? Follow the jump to see for yourself.

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    • 1 Second Ago
      • 4 Years Ago
      Um. That's not cold. I've got a 1981 Mercedes Benz 300D with 220k miles and it lights right up in single digit weather - without a block heater. The coldest I've had it sit overnight and still start without the use of a block heater (or the other heaters I've installed) is -12*F.

      As for VW not offering a block heater - boo on them. Fortunately, there are aftermarket oil pan heaters, battery pads, etc. available for those of us in cold climates. It's amazing how much difference a battery heater + oil pan heater makes on a cold start-up.

      • 4 Years Ago
      Great video!
      Maybe you could put a comparison up in the spring for how it does when it's a bit warmer out?
      • 4 Years Ago
      You would not believe it, but here in Europe we drive diesel powered cars the whole year even during the cold weather in the winter. I don't see the sensation here. Our TDI started up fine at -22°F after sitting for three days. The glow plugs just needed some time to warm it up.
      • 4 Years Ago
      Was that a cold crank?

      How long did you wait for the glow plugs to warm?
      • 4 Years Ago

      That is not "a lot of snow" and 25*F is not that bad as far as cold ....
        • 4 Years Ago
        That was my thought. I've only been here in WI for ~3 winters so far, and it was -17deg one morning on my way to work about 2 years ago. MI and MN get even colder.

        I'd be far more interested in whether the 2.0 diesel mill can start at those types of temperatures, as opposed to 25deg with a light dusting of snow on the ground
        • 4 Years Ago
        I remember one particular morning near Indianhead when it was about -20F and none of the cars would start. This was around 1976. There was a group of guys with a Pontiac Bonneville who jacked up the front of the car and built a fire under the engine. The rest of us just waited for a tow truck to come by and jump all the cars. I think we got going around 10 AM.

        Now that I'm older, I'm far too much of a wimp to ski at Indianhead again.
        • 4 Years Ago
        It was a lot colder yesterday in Milwaukee with those 40MPH winds and the blowing snow.
        I live a bit north of the city where it has been in the single digits (minus 5 to 10 with the wind chill) for the past week, yet my 180k 1998 Subaru starts up fine every morning.
        I once took my beater 1995 Neon up to northern WI in the winter and it got so cold the digital thermometer went off the chart (it got to -25 before it read "Err") and even IT started right up. No gas additives, no special (or even newer) battery.

        25. Pssh.
        • 4 Years Ago
        My friend in the UP has one and had a lot of trouble starting his last year. He called VW and said he didn't need a heater and indeed they do not even offer one. He's pretty pissed but spends more time in southern WI where it hasn't been as big if a deal. FYI Milwaukee is 15F right now, 25F is hardly cold. If he went back to the UP full time I can guarantee the Jetta would go. Sorry dudes.
        • 4 Years Ago
        if a car can't start in 25 degree weather, it shouldn't be on the market.
        • 4 Years Ago
        Agreed, 25 degrees F is not cold. -20 degrees F in the UP, with a 30 mph wind coming off Lake Superior? That's cold.
        • 4 Years Ago
        Forty years ago we cheated with a can of starting "ether" to get diesel tractors started in 40 degree weather. Modern diesels are pretty remarkable for those of us old enough to remember the old stuff.
      • 4 Years Ago
      So here's a 2006 Jetta at -17 Celsius. Is that enough for you nay sayers? no American diesel car can do this! oh wait America doesn't make diesel cars! IDIOTS!

        • 4 Years Ago
        That's still only ~1F. Go lower, please. This is nothing new or special - any modern car should be able to start at 0F without issue.

        As for the "no American car can do this" BS, what about trucks? I know for a fact that a Dodge Ram diesel will start relatively easy in -20F even with poor voltage.
      • 4 Years Ago
      Those poor ants.
      • 4 Years Ago
      1. if you mention the wind chill factor, you're stupid.

      2. if you compare it to your regular petrol car, you're stupid.

      3. 25* f is really not that cold, relatively speaking.
      • 4 Years Ago
      i live in northeast ohio (cleveland) and my '85 golf diesel never had problems in the cold. even when its below zero. same with my TDI.
      • 4 Years Ago
      Try this one on for size:

      3 Liter VG30DE Nissan Fairlady Z, Z32, Right Hand Drive, -32C with windchill, on 91 Octane gas?

      She does it everyday, no questions asked. Oh, and original factory OEM 1991 Battery too.

      I let her sit for about 2-3 minutes before driving her, and she jutters, creaks, and moans, and I can feel quite a noticeable loss in power, but all in all she still goes, and she comes from a climate where it almost NEVER gets below 5C.

      You think your Jetta was good haha...
        • 4 Years Ago
        Engines don't feel windchill. Use the real temp.

        Except for the 1991 battery thing I don't find this strange. I've only had one car in my life that wouldn't start, a 1982 Chevy Cavalier. It started like clockwork down to 0F, then below 0F wouldn't even think of firing (it would crank though). Maybe if it were a year later and had FI instead of a carb it would have worked.

        On a modern car, I don't even think twice. I would be shocked if any car I had (even my 10 year old Audi I just got rid of) had a problem starting above -20F, even if not properly prepped with higher percentage antifreeze and thin oil.
      • 4 Years Ago
      The video should show how long the key was in the ignition and rotated before the start... if the glow plugs warmed up the motor while he was talking, then really, this is a waste of bandwidth.

      25 degrees is not cold. It was 13 degrees the other night when I left my friends house at 1am and headed home. Doesn't matter how much snow there is or is not. 25 degrees is only cold if you are not dressed properly and wind up outside for longer than you planned.

      If this video wanted to do some good, it would explain why diesels are hard to start - the compression alone is a huge factor. Just like a race motor on gasoline that runs 14:1 or something crazy with wild cams.

      At one point in time several european brands were experimenting with heat storage tanks that could help warm up a motor to reduce emissions. I imagine the new glow plugs that heat faster and hotter help with the emissions more than anything, starting in cold weather is more to do with battery and starter condition, compression, oil weight, and making sure your fuel is treated. The quick hot glow plugs make it even easier.

        • 4 Years Ago
        I don't think this video accurately shows how long the glow plugs were on:
        1) VWs have 3 key positions (most cars have 4): Off, On and Start. The headlights were on at the begining of the video, which means the key was already in the "On" position. (If the key was "Off", you'd only have DRLs or nothing.) Since the key was in the "On" position, the glow plugs were definitely already on.
        2) When you unlock the car (with the remote or with the key), as soon as you open the driver's door, the glow plugs go on. The driver's door is already shown open, so the glow plugs were already going.

        Best control for glow plug "time to start" should be, walk up to cold, dark, locked car, unlock car, open door, sit, insert key, turn to "On" position and focus camera on glow plug indicator until it goes out, then start the car.

        Our 2011 Jetta Sportwagen TDI takes just a few seconds at these temps, the glow plug light is on for a second at the most (so far), but that includes the time it takes for me to open the door, sit down, put on my seatbelt (my habit) and turn the key.
      • 4 Years Ago
      You did it with the headlamps on?
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