Why are Diesel Engines Hard to Start in Cold Weather?

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[demontech]

I work on big 645 and 710 locomotive engines, and these have NO glow plugs. Locomotives typically stay running all winter long and never shut down. Locomtives don't run antifreeze. Some of them have air starters and some have electric starters. GE's have an inverter starting system, which means no physical starter. EMD's have either air, electric, or both. The only good way to start them when cold is with hot water. The engines have to be prefilled with hot water, then started. On rare occasions, we take rags soaked in diesel fuel, put them in the air boxes, and light the rags on fire to get enough heat into the cylinder to light them off. I've had calls from the fire department asking if we had a fire emergency when cold starting a locomotive. 😂 Such good times!

[minnesotatomcat]

My great grandfather used to tell us about back in the 30s living on the farm and dealing with motors in the winter. He said they used to have to drain the oil on the car when they got home from anywhere and keep it in the house next to the wood stove to keep it warm. And then quick fill it up right before they’d start it or it would never start in the cold on its own. I can’t imagine!

[johnnylightning]

I found a way to make my diesel easy to start in the winter, I take my RV down south and don't go back north until summer. I realize many folks, as in not retired like me, don't have that option so this was good stuff to know. Keep the good stuff coming buddy.

[stanpatterson]

Going back in time to when we used pony motors to start the main diesel, one of the strategies to a good start, was not to be in a hurry. Squatch 253 is a proponent of the "get the cylinders good and hot before sending in the fuel" way of doing things. That thing, is to let the pony motor spin over the big engine on compression for a while, letting some heat accumulate in the cylinders, before introducing what will be relatively "cold" fuel. This applies in all seasons, but is crucial in the cold.
Spraying the "cold" fuel, even in the summertime, into a cylinder where the rings might be tired, the valves may not be sealing well, whatever the reason, when you spray the fuel in, if things aren't hot enough in there already, the "cold" fuel is going to cool things right down and make compression ignition a whole lot harder.
Yes, in warm weather, if after the engine has been running already, you have a better chance of getting the big engine to fire on the first strokes, and it can be a success with injectors sending fuel instantly, but the warm-up-the-cylinders-first idea is a tested, proven method.
Fast-forward to today with modern, computer-controlled fuel injection diesel engines, and you will find that the ECM's are programmed to let the engine spin over a few complete revolutions before telling the injection system to begin firing. That gives the cylinders the best chance to build a little heat before the "cold" fuel start spraying in.
It might seem counter-intuitive to the beginner to be wasting battery cranking power allowing the engine to roll over several revs before firing, but that is the reasoning behind it.

[leelavinder]

I just rebuilt that exact model Kubota (L245D). That’s what I do full time (Kubota Technical), also I’m a full time Pastor. Have a blessed day.

[Truckguy]

Ive been working on diesel engines for about 4 years now, I’m only 19, I like to think I’m knowledgeable on the subject but you have been an invaluable resource in my journey to learning how these machines work, and it seems like I still learn something new every time you post one of these videos

[Flintlock]

Working in Upstate New York I have had a little experience with these problems both in the Army, Fort Drum, and working for SWIFT, Syracuse, as a mechanic. In the Army, I have had several different cold weather start systems Glow Plugs, and Either Start systems, and the best I experienced was in the old Deuce and a half trucks. They installed a spark plug into the intake and the firing of the spark plug would preheat the air. I never had one not start on the first try. When I worked for SWIFT Corporate would not let us cut the fuel in the wintertime. Jonestown PA could but according to them, it was not cold enough in Syracuse NY to require that. I would spend 12 hours a day outside rescuing gelled-up trucks in the yard. Pull the fuel filters and see the jello diesel sludge, replace fuel filters, and add Rescue 911 to the fuel, and the filter wait for a half hour, then start the truck and get the driver on their way. We were having issues above freezing one day and my manager questioned my intelligence because "there is no way these trucks are gelled up it 's not cold enough". I told him that you do realize that it is 36F with a wind chill of 20-something out. Trucks are not affected by windchill. Okay, buddy that big giant heat sink of an aluminum fuel tank sitting on the side of the truck is not being cooled below freezing while that wind is whipping around it. Has anyone ever heard of an air-cooled engine? Aluminum is a great conductor of cold. Take a warm beer place it on ice and spin it around a couple of times, you will have a cold beer pretty quick. This is why I was outside working in the big freeze, he thought it was punishment when to me it was a reward to be away from the idiot.

[jeffsnider]

I became familiar with the manifold flame system used on the M48 and M60 Army tanks that used the Continental 1790 engine. There was a flame generation device located in a steel section of the intake manifold where a hand pump operated by the driver along with energizing the starter solenoid would allow a spark igniter to build a flame in the intake. The electrical interlock with the starter solenoid was needed to prevent igniting the fuel if air was not moving in the intake. I have seen this system used on some European diesels also.

[coarsegrind]

Winter starting a Cummins 335 smallcam with a decompression lever was a dream starting in the winter.

[FireSprinklerTech]

I enjoy your videos. They help me understand a diesel engine better. I drive a bus for our church. We had an International with the DT466. That engine didn't like the cold at all. If it was much under 50f and you didn't plug it in, good luck getting it started. I replaced the glow plug solenoid because it wasn't working. That helped, but not enough. We sold it and it ended up in Florida. It should start fine there. We where blessed with two 2009 IC buses with the Maxxforce DT (I know not many would call that engine a blessing). I have them on a timer to run the block heater and a battery maintainer for 6 hours Sunday morning. Even though they will start in the cold, I figure its got to be better on them to use the block heater. Thanks for the videos.

[benjamincresswell]

Josh, as this is a "Topic Video" I wanted to chime in with my years and years of accumulated knowledge on them there ornery Diesels. I've had some experience with both glow plug and non glow plug diesels. 1). Early on I used to change the starting fluid cans on the Cummins 250's as a pm person at a huge truck leasing company out of Birmingham Alabama.(I worked in Detroit, Michigan) We also had "pellets" for the 2 cycle GM's. 2). I have a Ford Super Dexta 3 cylinder Perkins Diesel tractor that has a glow plug in the intake manifold. My local Ford Tractor Authorized repair guy says it actually makes a Diesel Fire inside the intake manifold. I thought it only vaporized the diesel fuel, but I've seen enough farmers light a wad of cotton dipped in Diesel on a coat hanger and hold it over the intake to start cold Diesels, that I'm inclined to believe him. 3). Later I had an opportunity to purchase a GM 350 Diesel car that was only two years old real cheaply but wouldn't start. Having farmer cousins with lots of experience with all things Diesel, they told me to get the biggest batteries I could find under the hood, & it'll always start. I bought two 1175 CCA batts called "ICE BREAKERS" from a drugstore turned auto parts store. They were bigger than anything on the market. Then I learned about glow plugs, and mine weren't working. The first thing I did was put a manual override "doorbell button" on the solenoid. Then I had to learn the GM glow plug system used 6volt glow plugs for quick heat up times. That means you don't just turn them on, you pulse them just enough to get the engine going. After a while I owned 4 GM Diesel powered cars at the same time with similar problems, because I could buy them relatively new for small money. I found out GM recommended a minimum 600rpm cranking speed to create heat for initial combustion. And even though you could blow a head gasket immediately using starting fluid, I found that you could use it if you only gave it just the tiniest tiny tiny shot. Then I learned when wife ran out of fuel to put a hose from the BBQ grill propane tank in the air inlet w/ just the tiniest tiny tiny shot of starting fluid and I could start up a dry fuel system and run it on propane coming directly off the propane tank with no regulator until the engine was running on it's own fuel. BTW, when I have a fuel pump issue on PETROL/ GASOLINE cars, the propane/ starting fluid deal works well enough to drive it away on the propane. You wouldn't want to do it in traffic, but out here in bug tussle, I drove my 1998 Yukon 5.7L gasoline Vortec 10 miles to a nice warm shop when it was 20°F outside, to replace the fuel pump using only my 20# BBQ grill tank. Sometimes I get them running on propane and hammer on the gas tank and if the pump comes back to life, the engine will chug like the choke's on, thus getting one more shot at driving it a bit further. I have run enough Diesels in cold climate to know all about running Kerosene below 10°F to avoid waxing or gelling. Some places told me I'm gonna blow my car up, but for the last 36yrs of my working life I worked with the engineers who developed the GM 350 Diesel and I got the skinny on it. The stations who didn't want me to put Kerosene in my car fuel tank weren't paying road tax on it as it wasn't a road fuel. What they weren't telling me was the truth: Kerosene is just Diesel cracked further or refined a little more until the wax is removed, as in Jet Fuel. The Truth Will Set You Free, if you take the time to learn it. Thanks for the channel Josh, it's always very interesting to see a professional walk right thru issues of such technical detail as you do. I'm old now, so I don't do much, but you take me places where I used to go daily. Thank You for going thru all the effort to video edit and post. ben/ michigan PS, have you ever used a snow blower? If you do you'll never look back.

[Brian-crrb]

No sound on earth can replace that engine firing up! Gave me goosebumps! I'm glad you keep her up and running. It's all about vapor pressure and flashpoint. As a hazardous materials specialist, I already knew. Your explanation is on point and very easy for anyone to understand. Great job!

[kevintakalo]

i have an old ford school bus with air start. Its got the new holland 7.8 turbo diesel. Ive never seen another school bus with air start. But its service life was up near seattle wa. My only thought was it was for cold weather start ups. It does spin over fast! I actually really like it. I can run the bus with a little pickup battery because there are no large 12v loads. Just gotta make sure you have good pressure in the tank.

[shanemjn]

IIRC old PSA diesels used a heating element built into the fuel filter.

[paullogan]

Josh, Keep up the great videos! 2016 unknown to me a lighting strike came close to my truck when at home. Took out all 6 injectors. Tow truck driver smelled the starting fluid and flipped out . Told him either leave or tow, but no bit****g. He towed. Arrived at dealer and Service writer asked. I asked how would you check failed start if you was a simple O-O/ He answered same. I mean 2 shots and it wont? To the shop it goes! $6800 tow, injectors, R&R. All 6 failed electronics.

[mikecollins]

I run Rotella oil in my diesels (5.9 Cummins and 3 cylinder Kubota) and I have found that switching from the T-4 (summer use) to T-5 or T -6 (semi/ full synth) for winter use makes them MUCH easier to start when it's cold. Keeping them "plugged in" (coolant heater in 5.9, magnetic/ block heater on Kubota) makes a HUGE difference, as did moving to a lower elevation (not a practical answer, but I noticed a big difference) Finally I run an additive in cold weather (Power Service white bottle).

[jean-lucgiorgetta]

Thanks for this very clear video. Many videos show big diesel cold starts (locomotive or generators), with much smoke, explosion sound and sometimes flames pouring from exaust. It looks like cylinders start one by one in fact.

[Skusty]

Here in northern Europe, we use auxiliary heaters that run on diesel and heat the coolant, used for both heating the engine and cab, set it on a timer and it's nice and warm in the morning.

Blockheaters are very common on smaller vehicles like cars and pickup trucks, plug the vehicle into an outlet and a coil in a water passage heats the coolant.

[oby-]

The formulation of mixing of chemicals are different for gasoline and diesel in the winter. There are highly aromatic or another way of saying it is quickly vaporizing additives in gasoline to help start in colder months. One proof of this is when you have old gas in your generator or snowblower and it is cold it will be hard to start if using old gas. Pour fresh gas in and it will usually start right up as long as everything else is maintained properly. Diesel doesn't have this advantage and relies on compression and heat to start the oil burning. When cold, the clearances change and get worse which again exasperates the problem.
And my 3406 never had a problem starting even down to -20, but below that I never shut it off when on the road.

[haroldenglish]

Alaska- run an extension cord to vehicles with 12 Guage wire to a 4 way outlet. 1 outlet has like a 2 amp trickle charger for batteries, 1 to oil pan heater pad, 1 to transmission fluid heater pad, and 1 to engine block heater. -70 Fahrenheit no problem. Set on a timer to start warming up 2 to 4 hours prior to wanting to start engine. Leave for work at 6am, set timer for 4am. Also saves a ton of money on electric bill! Lol