Diesel engine warm-up and cool down

[JDgreen227]

I drove medium duty commercial straight trucks for a living, many with diesel engines like a Cummins 5.9, so when I got my first diesel tractor it was second nature to let it idle for several minutes after starting and before stopping the engine.

Indeed, the operator manual recommends "let engine run at 950 rpm for one minute in warm weather or five minutes in cold weather after starting" and "let engine run at 950 rpm for about 2 minutes after hard or extended operation to prevent heat build up" (before shutting off).

After I start the engine, I move the tractor outside at idle speed, then let it run for a minute or two, and when done for the day, I shut off the mower, then run the engine at idle for 2-3 minutes before driving back indoors. I can understand the cool down process for a large, heavy truck engine, most of which are equipped with turbochargers, but does the cool down process for a small, non-turbocharged diesel really have that much effect on engine service life? Thanks for any input you can provide.

 

[Carl_NH]

Most manuals specify a warm up for the engine and more important the hydro fluids. On my B21 they say 1-2 min above 60* and below 45* 4-5 minutes.

On cool down aspects I think its a good idea especially if working it hard in hot weather however since its water cooled i dont really think its a big deal one way or another.

With air cooled units like my Cub or ZTR I pull up to the barn and blow off the grass and dust allowing them to idle for a few minutes to cool down. Sometimes on the Kubota I will give it a quick washdown but usually just the trip back to the barn is enough to cool off in my opinion.

 

[TripleR]

I just go by the manual.

 

[RPW]

I agree go by the manual. Shutting down a hot engine regardless of whether it's water or air cooled can be hazardous to the engine. Heat will build up after shutdown regardless of cool down period but how much heat will build up will differ. Try this, pick up an inexpensive non-contact temperature gauge (about $25 at HF). Run your tractor hard say discing or mowing for about an hour, before you shutdown get a reading off of where the cylinders are located. Shutdown and watch the temperature climb. Do it again but let the motor idle for a couple of minuets. The temperature will still climb but you will probably see that it doesn't climb as much and slower.

Good luck.

 

[RoyJackson]

I just go by the manual.

About the same...I let it idle long enough for the temperature gage to start moving, then go to work...now, if I'm going to use PTO RPM, I don't engage (the PTO) until the tractor is normal operating temperature. I normally do a walk around (looking for loose fasteners and damage) while I smoke a cigaret.

As far as shutdown...I'm on my 3rd Deere. None ran over quarter to third way up the gage during operation. I just shut down when I'm done (after reducing RPM and disengaging the PTO).

 

[JDgreen227]

About the same...I let it idle long enough for the temperature gage to start moving, then go to work...now, if I'm going to use PTO RPM, I don't engage (the PTO) until the tractor is normal operating temperature. I normally do a walk around (looking for loose fasteners and damage) while I smoke a cigaret.

As far as shutdown...I'm on my 3rd Deere. None ran over quarter to third way up the gage during operation. I just shut down when I'm done (after reducing RPM and disengaging the PTO).

By gage you mean temp indicator? I am always surprised at how cool my Deere runs, even when mowing at PTO RPM in 90 degree weather on a sunny day, my gage barely goes up to a third of the scale at the most. I usually give it a 2 to 3 minute idle speed creep to my mowing site, then engage the mower PTO, run it it 1500 rpm for a few minutes as I mow and gradually increase the rpm as the temp gage registers normal operating range.

 

[Thomas]

Like most I let the tractor warm up..colder longer,also raise fel and do bucket curls than 3 pt. hitch.
Cool down,couple mins. plus..take care of tools do tractor check.

 

[RoyJackson]

By gage you mean temp indicator? I am always surprised at how cool my Deere runs, even when mowing at PTO RPM in 90 degree weather on a sunny day, my gage barely goes up to a third of the scale at the most. I usually give it a 2 to 3 minute idle speed creep to my mowing site, then engage the mower PTO, run it it 1500 rpm for a few minutes as I mow and gradually increase the rpm as the temp gage registers normal operating range.

Yes, the temp gage...

My previous tractors were a 670 and a 790, both also ran as cool as your 4210 as does my 4400.

 

[JDgreen227]

Yes, the temp gage...

My previous tractors were a 670 and a 790, both close relations to your 770 and both also ran as cool as your 770.

I am a little HOT because you think my 4210 is a 770...nope, not really...lol

 

[RoyJackson]

I am a little HOT because you think my 4210 is a 770...nope, not really...lol

I went back and corrected it before you responded...sorry about that. I was thinking of another member who does have a 770.