Is it good or bad for a diesel to be ideling for any length of time? Other than air pollution, does it effect the engine any? Now Im asking about older diesel tractor engines, and newer cummins or powerstroke truck engines. I have heard 2 people say its the worst thing you can do to them,,, I dont believe it but?? J
- Thread starter JayinNY
- Start date
It's better than constant starting and stopping in the cold, but otherwise don't do it too much.
If you run it at idel too long and don't get them up to working temp, it won't burn the fuel right and it'll wash down the cylinder walls, contaminating the oil. It'll wet stack badly as well.
Newer trucks with computers will kick up the idle speed if the engine temp drops too much, so newer trucks have more leway when it comes to that situation.
Donovan from Wisconsin
If you run it at idel too long and don't get them up to working temp, it won't burn the fuel right and it'll wash down the cylinder walls, contaminating the oil. It'll wet stack badly as well.
Newer trucks with computers will kick up the idle speed if the engine temp drops too much, so newer trucks have more leway when it comes to that situation.
Donovan from Wisconsin
I've heard idling is bad for a diesel (or any engine for that matter) for an extended length of time. Idling doesn't keep engine up to proper operating temp., when the engine isn't up to proper temp it doesn't burn the fuel as efficiently. When I have to idle the semi I drive, I'll normally bump it up to at least 1000rpm, that helps keep the temp up.
I myself hate wasting fuel so once my Dodge is warmed up I'll shut it off if I'm going to be somewhere long. That engine will hold heat for quite a while. Just my thoughts.
I myself hate wasting fuel so once my Dodge is warmed up I'll shut it off if I'm going to be somewhere long. That engine will hold heat for quite a while. Just my thoughts.
PreciseFarms
Member
Around here the "cool" diesel people leave theirs idling unless they're parking it for the night. They seem to think its the thing to do so everyone knows you have a diesel. Drives my dad crazy. They always give the excuse that its better for the engine and fuel mileage to let it idle rather than shut it off for just 15 min. It goes for road tractors too. Dad always says to watch when the owner of the truck comes to get a load of grain and see if he lets it idle the whole time he loads, and we can load a truck in less than 30 min. at the bins. He will always will shut it off while an employee let 'er go. We don't even do that with a tractor or combine unless we're just getting off for a quick repair or to check something out. Sometimes if its longer its just to keep the cab cool.
OK, 2 more questions, In the winter, I plug in my tractors, start it clean the barn then let it sit outside for 20-30 minutes ideling to warm it up while I finish in the barn. Good or bad? 2nd, my truck, after driveing home from work in the summer I let it idel for 5-10 minutes to cool so the oil dosent gall on the turbo shaft bearings? good or bad?
For the turbo, the reason I was always told was to let the turbo and engine temp come down some before loosing the oil pressure and to also let the turbo slow down if you just got done running on the highway. Never heard of oil galling as a reason to idle, but they do say to idle for atleast 3 minutes.
For the warm up, as long as the engine is running on all cylinders and has pressure, you can go to work with it. Maybe start out light until it's up to temp, but it's not neccesary to idle that long. I'm guessing if you don;t do much to work it your deisel is starting to wet stack by the end of the winter season. Had a loader tractor (Oliver 1755) that was a diesel and that one would be wet stacked horrible by the end of winter. Just moving manure wasn't enough work for it in the winter so it never burnt all of the fuel. First chance we had we would work it some in the field to clear it up.
Donovan from Wisconsin
For the warm up, as long as the engine is running on all cylinders and has pressure, you can go to work with it. Maybe start out light until it's up to temp, but it's not neccesary to idle that long. I'm guessing if you don;t do much to work it your deisel is starting to wet stack by the end of the winter season. Had a loader tractor (Oliver 1755) that was a diesel and that one would be wet stacked horrible by the end of winter. Just moving manure wasn't enough work for it in the winter so it never burnt all of the fuel. First chance we had we would work it some in the field to clear it up.
Donovan from Wisconsin
Just to throw my 2 cents in here on the subject. There are really too many variables to say yes it"s always bad, or no it"s not always bad because every situation is different.
On the bad side any engine with a properly thermostat/temperature control system is going to eventually get to it"s correct operating temperature whether it"s ideling or no. During the summer months when it"s hot that"s not going to be a problem but it could be problematic during the winter when temps get down too low. That"s the reason you see trucks going down the road with covers over the grill to reduce the flow of cold air through the radiator which allows the engine to retain more heat. As for wet stacking it can and does happen but it"s just as much a result of ideling as it is of low exhaust gas temps. Basically there are no piston rings commonly in use, that I know of, that will provide a 100% seal, in other words all engines are going to "use" a little bit of oil wether they idle or not. So, basically ideling an for a few minutes here and there is never going to hurt anything as long as it is run under a load afterwards and exhaust temps are allowed to get to their normal temps and burn off any oil that may have accumulated in the exhaust system. On that note I have seen a crane that was idled day in and day out lifting light loads and it literally wet stacked to the point there was pure liquid oil in the muffler. When they finally wound it up and put it under a load for a few hours the muffler caught fire and burned all of the oil out. It was an old 2 stroke Detroit which are prone to wet stack anyway due to the design of the rings but proof of point is that the high exhaust gas temps got rid of the excess oil.
That said I"m talking about the older engines without all of the new, fancy exhaust systems using EGR, particulate filters, etc, etc. On those I don"t have enough experience with them to say one way or the other.
Now the pluses to ideling a diesel. One is turbo life. Regardless of whether you allow it to slow down, and cool down, or not, when you shut down the engine the oil flow to it stops. I"ve watched the turbo on a customers engine continue to spin for nearly 45 seconds after the engine was shut down. Granted in this application the engine was being shut down from it"s idle position of 1300 RPM but even at a more standard idle speed of say5-700 RPM even 15 seconds o run time without oil pressure wouldn"t be unheard of. The same goes for startup. The turbo is already starting to spool up by the time the oil pressure reaches it so there is going to be a lag time when it has no real oil pressure to speak of. There have been several ways to combat this problem put into production over the years from accumulators to standpipes to hole the oil, etc, but there is no replacement for using a good, quality oil. In my customers case changing to a better brand of oil took his turbo life from around 9 months to nearly 2 years.
To be honest beyond turbo life expectancy the only other plus I can think of is along the same lines. That is diesels typically have compnents weighing alot more than a standard gas engine. As such the crank lying in the bearings is going to tend to displace the oil film if left setting for any length of time. As a result you are going to have metal to metal contact for a split second after startup until the oil can get in place and do it"s job.
It"s a proven fact that the majority of engine wear is put on an engine wear is place on the engine at startup and shutdown for the reasons mentioned. So, if your starting and stopping your vehicle many, many, times a day then you might be better off to let it idle.... but for around town stopping like most people do then letting it idle is doing nothing but wasting fuel.....
On the bad side any engine with a properly thermostat/temperature control system is going to eventually get to it"s correct operating temperature whether it"s ideling or no. During the summer months when it"s hot that"s not going to be a problem but it could be problematic during the winter when temps get down too low. That"s the reason you see trucks going down the road with covers over the grill to reduce the flow of cold air through the radiator which allows the engine to retain more heat. As for wet stacking it can and does happen but it"s just as much a result of ideling as it is of low exhaust gas temps. Basically there are no piston rings commonly in use, that I know of, that will provide a 100% seal, in other words all engines are going to "use" a little bit of oil wether they idle or not. So, basically ideling an for a few minutes here and there is never going to hurt anything as long as it is run under a load afterwards and exhaust temps are allowed to get to their normal temps and burn off any oil that may have accumulated in the exhaust system. On that note I have seen a crane that was idled day in and day out lifting light loads and it literally wet stacked to the point there was pure liquid oil in the muffler. When they finally wound it up and put it under a load for a few hours the muffler caught fire and burned all of the oil out. It was an old 2 stroke Detroit which are prone to wet stack anyway due to the design of the rings but proof of point is that the high exhaust gas temps got rid of the excess oil.
That said I"m talking about the older engines without all of the new, fancy exhaust systems using EGR, particulate filters, etc, etc. On those I don"t have enough experience with them to say one way or the other.
Now the pluses to ideling a diesel. One is turbo life. Regardless of whether you allow it to slow down, and cool down, or not, when you shut down the engine the oil flow to it stops. I"ve watched the turbo on a customers engine continue to spin for nearly 45 seconds after the engine was shut down. Granted in this application the engine was being shut down from it"s idle position of 1300 RPM but even at a more standard idle speed of say5-700 RPM even 15 seconds o run time without oil pressure wouldn"t be unheard of. The same goes for startup. The turbo is already starting to spool up by the time the oil pressure reaches it so there is going to be a lag time when it has no real oil pressure to speak of. There have been several ways to combat this problem put into production over the years from accumulators to standpipes to hole the oil, etc, but there is no replacement for using a good, quality oil. In my customers case changing to a better brand of oil took his turbo life from around 9 months to nearly 2 years.
To be honest beyond turbo life expectancy the only other plus I can think of is along the same lines. That is diesels typically have compnents weighing alot more than a standard gas engine. As such the crank lying in the bearings is going to tend to displace the oil film if left setting for any length of time. As a result you are going to have metal to metal contact for a split second after startup until the oil can get in place and do it"s job.
It"s a proven fact that the majority of engine wear is put on an engine wear is place on the engine at startup and shutdown for the reasons mentioned. So, if your starting and stopping your vehicle many, many, times a day then you might be better off to let it idle.... but for around town stopping like most people do then letting it idle is doing nothing but wasting fuel.....
fixerupper
Well-known Member
And the "cool" people park their diesel right by the convenience store door so others can hear it.
A wheat harvester we briefly worked with rented a grain cart tractor by the hour for the summer harvest. For some unknown reason I haven't figured out yet, grain cart drivers don't seem to know how to shut the darned thing off when it's not needed for an extended time. That tractor sat and idled during lunch, it sat and idled while the combine was broken down, etc. When the season ended and it was time to turn the tractor back in the rental bill was huge!
The truckers did the same thing only they didn't have hour meters. Jim
A wheat harvester we briefly worked with rented a grain cart tractor by the hour for the summer harvest. For some unknown reason I haven't figured out yet, grain cart drivers don't seem to know how to shut the darned thing off when it's not needed for an extended time. That tractor sat and idled during lunch, it sat and idled while the combine was broken down, etc. When the season ended and it was time to turn the tractor back in the rental bill was huge!
The truckers did the same thing only they didn't have hour meters. Jim
guido
Well-known Member
Hello JayinNY,
If you are talking minutes of idling....NO problem. If you are talking overnight.....NO!
Most states have idle time laws that govern when and how long you can idle an engine.
But its (VERY BAD) for a diesel to idle.
BY design they need a very large cooling system.
Horse power dictates that.When at idle with no load, they run cool. This makes combustion incomplete. Run them under load all day........No problem.
Guido.
If you are talking minutes of idling....NO problem. If you are talking overnight.....NO!
Most states have idle time laws that govern when and how long you can idle an engine.
But its (VERY BAD) for a diesel to idle.
BY design they need a very large cooling system.
Horse power dictates that.When at idle with no load, they run cool. This makes combustion incomplete. Run them under load all day........No problem.
Guido.
As long as the engine can hold oil pressure at hot idle, there is no big problem. Many can't.
Diesels are very inefficient at idle and create a lot of soot, that's all. If done a lot, they carbon up unless you run them hard once in awhile to clean them out.
Some trucks in arctic areas are left running all winter, night and day - due to constant temps at 30-40 F below.
Diesels are very inefficient at idle and create a lot of soot, that's all. If done a lot, they carbon up unless you run them hard once in awhile to clean them out.
Some trucks in arctic areas are left running all winter, night and day - due to constant temps at 30-40 F below.
Ken Macfarlane
Well-known Member
Bad to idle, incomplete combustion. In winter engine won't get up to temp. The excess air moving through the engine keeps it below proper temp for oil/bearings.
the only reason i let my tractor idle in the winter if it"s plugged in is to warm the transmission oil up (connect a spool together with a pipe and set it a constant pumping), modern tractors with hydraulic clutches need warm oil... (my big Massey won"t even allow a gear shift when the transmission oil is too cold)
fyi i'm on the Canadian prairies... it's a balmy -2.5C here this morning...
fyi i'm on the Canadian prairies... it's a balmy -2.5C here this morning...
trucker 40
Member
The worst thing about idling a diesel that I can think of is that when its idling it doesnt have a lot of oil pressure in most cases.Then the top of the engine might not be getting oiled good,so it wears on the top engine parts.Also when its cold the oil doesnt run back down as fast and especially the turbo has oil built up around it,possibly seeping into the cylinders and causing a lot of smoke when you wind it up again,and also soot builds up on the valves and on top of the pistons.On an old Cummins thats idled all night there will be a trail of oil coming off of the turbo usually and even out of the exhaust manifold.As this oil gets hot and burns it can sometimes burn the exhaust manifold gaskets out.
If you drive a truck over the road,and if you park somewhere in the hot summer or cold winter you will idle it.You cant afford the fuel to rev it up all night.The idle laws are ridiculous.I bet if the people who made the idle laws had to sleep outside in 20 below zero weather there wouldnt be any anti idle laws.Or for that matter when its 90 degrees at night and no air conditioner.Same thing.They do have power packs,but one of those thats wore out will smoke bad too.
There is probably not going to be any stopping of idling trucks,especially while the economy is bad.They will be lucky to get trucks to bring stuff the way things are now.
A lot of stuff put out by people about trucks is to make it harder on them so bigger and bigger companies get more and more business as they run small companies out.If they could get people to drive a truck with no cab on it,they would.The only reason they have sleepers and AC and a heater is to keep people driving them.The crooks dont care if they live or die,they just want them to drive like a slave.
If you drive a truck over the road,and if you park somewhere in the hot summer or cold winter you will idle it.You cant afford the fuel to rev it up all night.The idle laws are ridiculous.I bet if the people who made the idle laws had to sleep outside in 20 below zero weather there wouldnt be any anti idle laws.Or for that matter when its 90 degrees at night and no air conditioner.Same thing.They do have power packs,but one of those thats wore out will smoke bad too.
There is probably not going to be any stopping of idling trucks,especially while the economy is bad.They will be lucky to get trucks to bring stuff the way things are now.
A lot of stuff put out by people about trucks is to make it harder on them so bigger and bigger companies get more and more business as they run small companies out.If they could get people to drive a truck with no cab on it,they would.The only reason they have sleepers and AC and a heater is to keep people driving them.The crooks dont care if they live or die,they just want them to drive like a slave.
I cant see any benefit with the truck for that long an idle. I've replaced one turbo since 1982 and I'm not really sure it needed it. Usually a few second idle after a long hard pull is all any of mine get to cool down. I think if you go with the mfg recommendations a 2-3 minute cool down is plenty.
Worse thing you can do for a diesel is start it - they have real poor start up preformance & wear issues.
If you live in a northern climate like me, idling is just a part of using the machine, you got to keep it warm or get to electricity, after an hour at below zero you can start getting into starting issues....
So yea, it's hard on it to sit there not doing anything but run, and many will run too cool at idle.
But, do what you gotta do.
Shiting it off for 5 minutes and restarting it is probably worse on the wear & pollution than just letting it run that short time.
--->Paul
If you live in a northern climate like me, idling is just a part of using the machine, you got to keep it warm or get to electricity, after an hour at below zero you can start getting into starting issues....
So yea, it's hard on it to sit there not doing anything but run, and many will run too cool at idle.
But, do what you gotta do.
Shiting it off for 5 minutes and restarting it is probably worse on the wear & pollution than just letting it run that short time.
--->Paul
rustred
Well-known Member
that is very true, idling is not good for any engine. were talking long extended periods like hrs at a time, even days.one example would be oil field vehicles in winter where they run steady from job to job and dont get shut down. many people use their vehicle as their motel. with this being said , this puts greater wear on the valve train components. such as camshaft lobes ,lifters, rockers and valve guides. this is due to the engine operating at low oil pres. at idle. thats why its important to run them at at faster idle,even to keep the diesels warmer. this 1/2 hr or 1 hr. stuff is not so critical as you need to warm an engine up and cant always being starting and stopping them which is no good either.when i worked in the garage i replaced many camshafts for this reason.and another reason , this idling really carbons up everthing in the combustion chamber.
Do you have a reading-comprehension problem?
Re-read my post. I said "many", NOT "most" as you claim. If you have an argument with something I've said - OK - but at least make sure I acutally SAID it.
Detroit Diesel two-stroke-cycle engines are known for having poor oil pressure at hot idle. I'm sure there are MANY of them. I've got three. All run great and all drop to near zero PSI at hot idle - even with straight 40W Delo.
Also, Deere 300 series four-cylinder engines are known for low pressure at hot idle once the balancing shafts get a little worn.
Re-read my post. I said "many", NOT "most" as you claim. If you have an argument with something I've said - OK - but at least make sure I acutally SAID it.
Detroit Diesel two-stroke-cycle engines are known for having poor oil pressure at hot idle. I'm sure there are MANY of them. I've got three. All run great and all drop to near zero PSI at hot idle - even with straight 40W Delo.
Also, Deere 300 series four-cylinder engines are known for low pressure at hot idle once the balancing shafts get a little worn.
Funny. I was wondering the other day just how many of the green demons were actually built over the years. I was standing in a buddy's yard and heard what sounded like a 318 top Kelly's mountain... then he hit the switch and I listened to it bark, steady... for close to 5 miles right to the bottom. This at close to 5 miles away...
Rod
Rod
Billy Shafer
Well-known Member
I have seen Detroit,Hercules,Buda and some others drop oil pressure when at hot idle.
Also if an old Detroit is not leaking oil. Something is wrong.
Also if an old Detroit is not leaking oil. Something is wrong.
guido
Well-known Member
Hello jdemaris,
Them old Detroit Diesels would drop to 5# or less at idle, when hot. At overhaul time, I would shim the oil pressure regulator about 1/8",with a stainles washer inside the regulator housing. That increased the cold pressure from about 50 to about 60 Lbs., and the hot idle pressure from 5# to a least 10#. Low oil pressure lights used to come on a 5#. That way the drivers would not be complaining of the low oil ligth coming on at times. Oil type and temperature would play a part as well. But that 1/8 shim did the trick!
Guido.
Them old Detroit Diesels would drop to 5# or less at idle, when hot. At overhaul time, I would shim the oil pressure regulator about 1/8",with a stainles washer inside the regulator housing. That increased the cold pressure from about 50 to about 60 Lbs., and the hot idle pressure from 5# to a least 10#. Low oil pressure lights used to come on a 5#. That way the drivers would not be complaining of the low oil ligth coming on at times. Oil type and temperature would play a part as well. But that 1/8 shim did the trick!
Guido.
Anonymous-0
Well-known Member
Recieved a call one Monday morning, to fix a lowboy tire, when I got there the 450 Jd crawler was sitting there ideling. the boys left it running to cool it down and forgot to shut it off, ran all weekend. dont think it hurt anything except the fuel bill.
I've got two that, with original oil pressure gauges that swept 0 to 80 PSI . . . and would read zero at hot idle. So, I stuck in 40 PSI gauges that are more sensitive. Now both read around 2-3 PSI when hot at idle. That's OK with me. Main thing is that there is SOME pressure to avoid metal-to-metal contact in the moving parts.
guido
Well-known Member
Hello jdemaris,
I was never confortable with 5# , and the idiot light flashing occasinally.
That washer thing was my fix. I left the bypass regulator at factory set of 100Lbs.
At the time DD frowned on multi viscosity oil and we were usind Mobil Delvac1 15w40.
No problems related to the oil.
100.000 miles between oil changes in the cranckase
filters at 20.000 miles.
Guido.
I was never confortable with 5# , and the idiot light flashing occasinally.
That washer thing was my fix. I left the bypass regulator at factory set of 100Lbs.
At the time DD frowned on multi viscosity oil and we were usind Mobil Delvac1 15w40.
No problems related to the oil.
100.000 miles between oil changes in the cranckase
filters at 20.000 miles.
Guido.
guido
Well-known Member
Hello jdemaris,
I was never confortable with 5# , and the idiot light flashing occasinally.
That washer thing was my fix. I left the bypass regulator at factory set of 100Lbs.
At the time DD frowned on multi viscosity oil and we were usind Mobil Delvac1 15w40.
No problems related to the oil.
100.000 miles between oil changes in the cranckase
filters at 20.000 miles.
Guido.
I was never confortable with 5# , and the idiot light flashing occasinally.
That washer thing was my fix. I left the bypass regulator at factory set of 100Lbs.
At the time DD frowned on multi viscosity oil and we were usind Mobil Delvac1 15w40.
No problems related to the oil.
100.000 miles between oil changes in the cranckase
filters at 20.000 miles.
Guido.
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