Diesel Warm-Up -- How Long -- Why?

[Dr_Zinj]

Diesel engines, like all heat engines, are more efficient at higher temperatures.
You're not going to have maximum power available, and you're going to make a lot of pollutants trying to work before it's warmed up.

Internal combustion engines are lubricated with oil. When it's cold, that oil is more viscous (doesn't flow well). If the engine has been sitting unused, all the oil is at the bottom, and almost none of it is lubricating the parts at the top of the engine. Warm up makes the oil flow better, and pumps and splashes it all over the moving parts inside the engine. You want your engine well lubed before you put a load on it.

I always figure, barring owner's manual instructions to the contrary, that if your machine has a temperature gauge on it, don't operate it until the gauge starts registering.

 

[milkman636]

It's been a while since I've looked at my operators manuals. IIRC my Deere manual says that extended idling at low rpms will contibute to carbon build up in the upper cylinders. It recommends keeping the idle @ 1200 rpms or higher for my 5210. The low idle is intended for cool down before shutting the tractor down. I also seem to remember that it specificly directs me to wait until the temperature is registering on the guage before moving the tractor. So that's what I've always done.

It seems like this is a subject that should be covered in all of our tractor manuals.

 

[JDgreen227]

May be a stupid question, but does anyone know what temp the coolant gets in a modern diesel tractor system when they are fully warmed up? Reason I am wondering is because my car has an electronic temp readout as well as a temp gage and it runs at about 203 degrees when fully warm. JD has only a gauge and I have no idea what the readout actually means, degree wise. Thanks.

 

[milkman636]

Again IIRC, the thermostat opens around 160 and is fully open at 185.

 

[Short Game]

My Cub Cadet (Mitsubishi) 27 HP never gets warm unless it's really working at top RPM in hot weather. I run it with cardboard over the radiator in winter just to get the thermostat to open.

 

[RoyJackson]

My Cub Cadet (Mitsubishi) 27 HP never gets warm unless it's really working at top RPM in hot weather. I run it with cardboard over the radiator in winter just to get the thermostat to open.

I've had 3 Deeres (670, 790 and 4400) and have yet to see the temperature vary. They all run at 1/4 to 1/3 up the scale, regardless of work load or ambient temperature.

 

[wade simpson]

Like some here I flash it up, have a smoke then drive it from my parking spot to my road in low range first gear (about 10 mins). I never start working until the guage indicates that the temp is at operating range.
In the winter I generally have to get snow outta the way so it runs a bit longer. I bump it up to 1500 after a few minutes or when I guess the oil has gotten where it's needed.
My tractor CK20s Kioti) makes some weird sounds until its warm, clunking and snapping. I was a little concerned at first but it a consistant thing and the sound diminishs as it gets warm.

 

[SPYDERLK]

When its very cold my diesels run ruf at start ... its a pretty obvious difference from normal. I pay no attention to the gauge, but to throttle response and sound . As soon as they smooth [30 or 40 sec at 0F] I move toward the place Im going to work at around 1200 rpm while operating the hydraulics. - After initial light articulation, holding curl and running the fluid thru the relief warms it as fast as possible. Usually everythings happy by the time I get to the work location. In the cold I keep the rpms down to ~1500 for several minutes.
larry

 

[donn12]

I run mine at low idle (900 or so?) for a minute or two then raise rpms to 1400 or so to smooth it out. If really cold outside I will let it run like this for a few minutes, if not I will drive it to where I will use it on my property. For cool down I get an ICE cold beer or 2 and putter around on the tractor making plans for future projects. I run the tractor at 12-1400 rpms for this.

 

[Tractor Seabee]

In my younger day I overhauled a lot of rotating equipment for a living. Even was good a re-countouring babbit bearings by hand. The new high speed stuff never lasts a long as the old slow moving stuff. Check it out; stationary equipment that runs all the time at a steady speed and load lasts forever. Starting and stopping are the hardest thing you can do to any rotating equipment. It takes a few seconds to get the lubrication fully coating bearing surfaces. So each start takes many hours of running time off the parts. The new tractors w/auto trannies should last longer as you are running the engine at a set speed and adjusting the speed with the transmission instead of the throttle. I always warm up to op temp before moving. I keep my tractor running at idle unless not going to use it for 15-20 minutes sometimes more. Fuel, is cheaper than wearing out parts plus labor to overhaul, especially when it takes two hours of mechanic time to remove stuff so you can do a 15 minute job, and then put it all back together. I dread the day I have to work on the hydraulic system on my BX 25, even have to remove the battery and body parts. My military time in heavy equipment management also reinforced these lessons.

Ron