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JimMorrissey
Veteran Member
LOL...Yeah, that pretty much what I do. I figure getting back to the garage at 1500 rpm is plenty.
cool idle.....
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JimMorrissey
Veteran Member
It's not that I have my mind made up, that's why I asked the question. It's just that I have not heard a good reason yet /forums/images/graemlins/tongue.gif My Kubota temp rises to mid gauge (unknown temp) and stays there no matter what kind of work I do. Idling the machine has not effect on the stated temp one way or another. -I do idle, but only for 20 seconds or so for the internal pressures to equalize. I wasn't thinking of heat, but maybe I should be.
Maybe it would be a good test sometime to see if the heads are substantially hotter or cooler based on idling practices......
Maybe it would be a good test sometime to see if the heads are substantially hotter or cooler based on idling practices......
v8dave
Platinum Member
Jim, I think it has do more with the load on the engine rather than just the engine speed. If you were working it hard for all the time it was it was running fast, I'd say let it run a few minutes to equalize the engine temps. But if you were doing light mowing for all that time and the engine wasn't under load it'd likely not do too much harm. However, if you were plowing or bush-hogging I'd let it run for a bit before shutting down.
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JimMorrissey
Veteran Member
Start up certainly.....I let the machine idle for 5 minutes under spring/summer/fall and up to 20 minutes or more depending on the degrees below zero I'm dealing with /forums/images/graemlins/grin.gif
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JimMorrissey
Veteran Member
I agree. I was using RPM to provide a level of load. I don't run that high unless I'm really using the PTO or the backhoe and want some really fast swing speeds and/or digging power. My hoe runs a lot faster at 2400 RPM than at 1600 RPM. I like the speed and the extra pressure in the system sometimes and I happen to be using it hard these days.....that's one of the reasons I started this post.
Normally it takes me a couple of minutes to return to the barn, and I run about 1500 RPM or less, so I'd think that should do it for cool down. Maybe not.
Normally it takes me a couple of minutes to return to the barn, and I run about 1500 RPM or less, so I'd think that should do it for cool down. Maybe not.
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JimMorrissey
Veteran Member
That's what I was thinking as well. Liquids are not moving as quickly and the temps may actually rise idling. That's why it would be fun to test the theory....when I have some time to "test" things. Yeah right /forums/images/graemlins/smile.gif I may do sometime just for fun.
How many cars have you seen overheat in the blazing sun stuck in traffic....coolant spewing all over the place from sitting too long and idling. Interested to know. If I were a betting man, I put my money on the fact that it doesn't make much difference one way or another in a new clean engine (not caked with grease/oil and mud). I keep my engine clean so it can cool quickly......makes it look good too.
How many cars have you seen overheat in the blazing sun stuck in traffic....coolant spewing all over the place from sitting too long and idling. Interested to know. If I were a betting man, I put my money on the fact that it doesn't make much difference one way or another in a new clean engine (not caked with grease/oil and mud). I keep my engine clean so it can cool quickly......makes it look good too.
I dont know that I have ever read it in print anywhere. However, it is a fact that diesels will cool themselves at an idle and create a fair amount of heat under load at higher RPMs.
I have always been told and recomend others to allow your diesel to idle down before shutting it off.. It's never been an inconvenience and I dont see why anyone wouldnt let it idle.
Think of it like a marathon runnner, after the race, they are required to walk for a few minutes to cool down. Same principle.
I have always been told and recomend others to allow your diesel to idle down before shutting it off.. It's never been an inconvenience and I dont see why anyone wouldnt let it idle.
Think of it like a marathon runnner, after the race, they are required to walk for a few minutes to cool down. Same principle.
thcri
Elite Member
</font><font color="blue" class="small">( Lots of people don't idle their engines before shut down. UPS comes to mind; if anyone would know the adverse effects, if any, from not idling, they would.)</font>
All the UPS trucks in our area are gas. Only the over the road trucks are diesel. All delivery are gas at least in our area. Gas is a whole different subject.
murph
All the UPS trucks in our area are gas. Only the over the road trucks are diesel. All delivery are gas at least in our area. Gas is a whole different subject.
murph
Boomerang1
Gold Member
</font><font color="blue" class="small">( "Is there any particular reason to idle a diesel that may have been running at 2000-2300 rpm for a couple of hours?
That's always been a confusion factor for me. My tractor runs at the same temp whether it's idling or operating at 2200rpm. Any/all cars I have ever had always run a little hotter when idling, I guess, due to slower waterpump/fan/air speed. Does the combustion chamber actually cool down at idle without showing up in the coolant? )</font> Your tractor may run the same temp at idle or 2200 rpm but, when you shut it off, it gets hotter. The engine always gets hotter when a engine is turned off because the water and oil are no longer circulating and can not carry away the heat. I alway cool down and engine before shutting down.
That's always been a confusion factor for me. My tractor runs at the same temp whether it's idling or operating at 2200rpm. Any/all cars I have ever had always run a little hotter when idling, I guess, due to slower waterpump/fan/air speed. Does the combustion chamber actually cool down at idle without showing up in the coolant? )</font> Your tractor may run the same temp at idle or 2200 rpm but, when you shut it off, it gets hotter. The engine always gets hotter when a engine is turned off because the water and oil are no longer circulating and can not carry away the heat. I alway cool down and engine before shutting down.
Highbeam
Super Member
This is a good post. A good question. Does anyone's manual actually require cool down time? Mine doesn't but I assume it is wise.