How Long To Idle A Diesel Truck Before Shutdown And Why

[@Bloodbain88]

Dont forget how hard a hot shutdown is on an exhaust manifold too. I let someone borrow my 12 valve. He hauled a trailer for 3 hours straight at highway speed. Pulled off into a rest stop and immediately shut off the engine. He said he heard a loud metallic "POP" and the rest of the drive he could hear a rushing sound. The exhaust manifold had cracked wide open. There was a good reason all diesels in things like school buses and military equipment used to have plackards on them that said "Driver MUST idle engine for 3-5 minutes before shutdown!"

[@jshoptaw5862]

The term is coking. It will also cause the oil to breakdown prematurely.

[@ryanapted3598]

Turbo timers have been available for decades, I take it easy for the last few miles of my journey.

[@GStreat]

Great video. People think I’m crazy when I do this but they just don’t know what they are talking about.

[@AK_5.9]

Thank you, yes consistently doing hot shutdowns can shorten the life of the turbo

[@jamespatton2975]

I ALWAYS IDLE MINE ! ALWAYS LET IT COOL !

[@GStreat]

@ 🫡🫡🫡

[@davidtipton7234]

Think that's funny. My 2nd gen has a edge box with a turbo timer. I can shut it off and be halfway across the parking lot before it shuts down. People looking at me like wtf.

[@GStreat]

@ interesting!

[@alabamamotionpictureproduc6626]

In the Navy I worked as a mechanic on turbo prop engines and anytime we would run up the aircraft engines we would have to run them in "low speed ground idle" for two minutes before shutdown for exactly this reason. Once when I was cutting really high grass in a field, I noticed my temp gauge going into the danger zone. My first instinct was to shut it down and let it cool, but I came to my senses and just turned off the PTO, put the throttle back to idle and let it cool down while that oil was still pressurized.

[@KRShields]

The quadzilla tuner for my 98.5 cummins has a cool down mood. After the key is removed the engine stays running until the egt temp gets below a set temp. I set it to shut off when it gets below 295 degrees

[@idahobuckaroo8348]

Good advice for new turbo diesel truck owners. 👊

[@AK_5.9]

You bet, good turbo hygiene is important 👍

[@8alakai8]

not only diesel all turbo engines.i do think some have electric oil pumps to save the turbo when you just shut it of

[@82raptor]

I owned a turbocharged car in the past and I always did this. Another thing to not do is to get on the throttle when it is cold (as with any engine). People that don't know what they are doing is what keeps me from buying a used ecoboost car/truck.

[@dgpop1287]

good talk. owner manual of volkswagen diesel engine talk about around 3min of idle before shut down too!

[@brianmaloney5430]

Most new turbos also use coolant to cool the turbo.

[@corythomas4427]

It took diesel turbos a long time to start running coolant, some still don't. Seems like the bigger the (factory) turbo, the less likely it has coolant running through it.

[@dadgarage7966]

This knowledge is especially important for commercial drivers who don't own the trucks (rentals, bus drivers, etc.).

[@mance985]

I use to run a delay switch on my cummins. Would idle with the key out until EGT was down to 275F if i remember correctly.

[@leebuck180]

Thanks for this video, this also applies to turbo gasoline engines. On anothet video, a 1.5L turbo engine that went bad at 93,000 miles with melted pistons and a bad turbo (excess play in the shaft).

[@frankcostanza6770]

For normal driving, I typically let the egt get down to 300 or lower for at least 30 seconds to a minute. Now if i ran it hard or towing, Then I'll let it idle for a good 5 minutes before i shut down

[@davidallen5976]

Military vehicles through the 90s and 2000s had placards that said idle for 5 minutes before and after use.

[@AK_5.9]

Great to know that this is right in line with what I do on my 2003 Cummins, and what I recommended in the video. Thanks for the comment!

[@cloggedpizza239]

This makes sense. On ships we run the lube pump for a while after the engine in off to ensure we do not cook the oil which can damge its lubricating properities and also its anti corrosion properties. Also help cool the engine evenly.

[@joecummings1260]

Back in the 60's and 70's Mack used to put a plaque on the dash of turbocharged engine trucks saying to idle 3 minutes before shutdown

[@motorenbastler9289]

Well its only necessary if you have been driving under high load like on the highway. You dont need to do it ive you have been driving in a 25 zone for 2 miles until you get home. Than you dont need to let it idle

[@AK_5.9]

Yes that is true. It still wont hurt anything to let it idle for a bit, but it isn’t necessary if it never got hot.

[@theanimeotaku2794]

​@AK_5.9 it will hurt something are atmosphere

[@Keith80027]

Good advice from someone who has been driving a turbo diesel for over 24 years.

[@chrissmith7669]

I idle my turbo VW until the temperature normalizes. Just like we do aircraft turbines

[@stephenwest798]

One should even warm their gas engine up to normal operating temperature before getting on it hard and I always idle them for a minute before I shut them off. And yes, timely oil and filter changes help and the higher the miles the more frequent the oil changes.

[@nickc7320]

Nope. Idling the engine up to normal operating temperature is super excessive. That could, depending on temperature, engine, etc take 10+ minutes or the engine just won't get up to temp. Let it warm up for a couple minutes. Then drive slow into up to temp. Also the transmission needs to warm up as well. It doesn't really warm up until you drive it.

[@stephenwest798]

@@nickc7320I did not say idle until up to operating temperature, I said, and I'll rephrase it, one should wait until their engine is up to operating temperature before getting on it hard. That said it does not harm them to idle for a minute or so while you're scraping the ice off your windshield, been driving for 65 years and haven't lost an engine yet. I don't allow my newer engines to idle for long periods, but my older Chrysler engines with the oil running into the lifter gally I don't worry about one bit and will let them idle for longer periods. And not only the engine and tranny need to come up to operating temp but so does your differential and wheel bearings.

[@Michael-1337]

Some modern turbo engines are coming with backup circulation pumps that continue to circulate oil and coolant even after shut off.

[@clydesuckfinger8068]

On your 2019 F350, when I’m towing (which is normally what this truck does), I’ll let it idle to get the oil temp down to 199 degrees or less. Why 199, beats me, just sounds like a good number.

[@jeroenhaentjens9156]

Can you tell me more about that display? Looking for this!

[@yesdeere1376]

Looks just like mine. Smarty touch.

[@snivesz32]

Installing an oil cooler would also be really beneficial.

[@snivesz32]

I usually drive the last mile real conservatively(no boost) and then idle for 1 minute.

[@hammer-r]

Yup and if u live in a subdivision, it’s easy to travel slowly. I do the same. When I tow, I never shut down when refueling. I wish the trucks had some kind of turbo saver, where oil would still circulate after shut down.

[@smurface549]

@@hammer-r Modern turbocharged petrol engines do that. They have two electric pumps, one for oil and one for water, both pushing the corresponding fluid through the turbocharger. VW/Audi introduced that back in 2008 I think, so "modern" is maybe not the right term anymore. No idea about Diesel engines though. My newest Diesel engine is some 39 years old and definitely has no intelligence on its own.

[@HR-rt9nh]

yeahp best way to cool down... is slow down before your gonna shut off. its also a good as you dont want your neighbors thinking your one of them crazy nut drivers.

[@heliwrecker8649]

350 dungarees and still dropping, if you have an egt sensor. Reality is if you get off the highway and have a couple minute easy drive through your neighborhood to your house, more often than not its below that temp. Only need to idle it to cool if you're gonna shut down right off the highway or just been pulling something. But yes, excessive idling can cause you to wash your cylinder walls with diesel and dilute your oil/ excessive cylinder and ring wear. You'll smell it on your dipstick if you have worn rings. Better to idle to cool at about 1000 to 1200 rpm to have full oil pressure till it nears 350, dead reg idle for a minute. Dead idle is the worst for a diesel except when it's stone cold starting up in the morning.

[@NMode_VN]

I drive a 2022 Veloster N. Hotter under the hood of that car than any I've ever owned. When I garage it knowing I won't see it for a week or two, I leave the hood open after I park for a few minutes. When I drive hard, like going up the Mount Washington Auto Road, I always idle it, hood open until the oil temps come back to normal, in my case 199-203.

[@biohazardousBiker]

I looked up the max temp my oil could handle and waited till my egt was about 10 degrees below that to allow for any heat soak.

[@AK_5.9]

Sounds good 👍

[@tomrunning357]

After getting off the highway heading to my destination I will drive it easily and let it idle for a while (five minutes)and longer if I was towing.

[@doodskie999]

Dont think this applies to newer turbos now. Newer ones are also cooled by a separate coolant lines. Also, getting to your house from the driving off the freeway is enough to cool the exhaust and turbo. Never had a turbo fail on me, I always change the oil every 7000 miles or 10000 km.

[@cbylsma626]

Nope, I have yet to see a coolant line to a turbo! The oil bath is what "cools" the turbo, coolant is not designed to handle the temperatures turbos get to, it'll boil off before is has a chance to cool it. Like hitting water to a hot piece of metal, it beads up and skates off!

[@doodskie999]

@cbylsma626 new cars have them, my ford ranger has a turbo coolant line

[@cbylsma626]

@doodskie999 there you go lol, I learned something new! I'd still keep to the older habits of letting it cool for a few minutes, just to be sure! Ive been trucking for 29 years and found that if I take the time to sort out my stuff, it tends to be long enough to allow it to cool enough! Which usually is around the 3 minute mark!

[@andymike6575]

@@cbylsma626 Why does the stock VGT on my ‘18 ram 6.7L Cummins have both coolant and oil lines lines running to it then?

[@kentsmith4863]

I do it as well for my Diesel engine but what about turbo gasoline engines with auto start stop?

[@AK_5.9]

I know the turbochargers on my wagoneer are each cooled by oil and coolant. There is an “after run” pump that continues to circulate coolant through the turbos after shut off. I’d suspect other newer turbocharged gassers with auto start stop have similar setups.

[@corythomas4427]

I've never heard this theory. Biggest issue I've heard of is oil coking in the drain tube, and that's more on gasoline engines with much smaller tubes and usually when they have an after-run coolant pump that isn't working.

[@jerryhaveman5659]

Why not run a turbo timer?

[@surfstarcc1]

Great video, you are correct.

[@robsavoy9339]

While it’s in regen should you just shut it down or wait until it’s done?

[@cbylsma626]

Wait, it's superheated the system to burn off the soot in the DPF filter, this will increase the whole exhaust temperature exponentially (in excess of 1000°) including your turbo! At these temps it can potentially shorten the time it takes to fail

[@alkalk8938]

This is far more important on older turbo engines that are not cooled with engine coolant. You dont need much idle time for liqued cooled turbo engines under normal circumstances.

[@larrythompson5617]

So give me a time frame. I have a 2003 6lt with 300,000 kms and have never done this but will start.

[@AK_5.9]

Three to five minutes should be good for a purely oil cooled turbo that has been run hot.

[@charlesb4267]

I've been wondering something for some time now that relates to what has become the proliferation of turbos on gasoline engines and then more recently the stop/start system. For one thing I think the typical gasoline engine owner with a turbo never lets the engine idle to cool, for another the idiotic stop/start system is going to shut the engine down the moment one comes to a stop. I have to wonder if its for reasons like this that some owners of turbo gasoline engines are having some dismal results with turbos failing.

[@AK_5.9]

That is an excellent point you bring up and a valid concern. I have a twin turbocharged jeep wagoneer which is cooled by oil and coolant. It overcomes the need for an idle cool down time by utilizing an electric after-run” pump which continues to circulate coolant through the turbochargers for a time after shut down. I’d suspect other newer turbocharged gassers have similar setups.

[@gearhead7896]

Just get a turbo timer.

[@chadleitschuh3012]

Problem with ideling is when you have a dpf and EGR then you cause problems with them

[@rhod8201]

Bad thing is all that idling will plug up your DPF.

[@joel387ktm]

This is 100% right

[@KnuckleDragginDad]

No shit? I never knew this. I’m fairly new to owning a Turbo Diesel. I’ve put about 10k miles on my Cummins TD since owning it. Hope I haven’t jacked it up.

[@AK_5.9]

They can tolerate alot of it, but over time consistently doing hot shut downs can shorten your turbo life

[@motorenbastler9289]

nah dont worry. If you have been driving under high load or high speeds and want to shut it off you should let it idle. If you have been driving in a 25 zone for like 2 miles and you get home you can shut it off instantly, without having any issues.

[@bobkanno6797]

As noted in another comment it is only necessary if the engine has been run hard or if you have been on the highway towing, let it idle for a few minutes. Excessive idling can also be counterproductive especially in cold weather, if the cylinder temps. get to low fuel can wash down the cylinders. If you are driving for several miles after hard use your cylinder temp and turbo has already cooled down. This is when a pyrometer is beneficial.

[@KnuckleDragginDad]

@ Thanks for the info. ✌🏽

[@davidpotter7484]

@@bobkanno6797 a pyrometer is showing the temp of the exhaust gas, not the exhaust manifold itself. Cast iron and steel retain heat rather well, and after shutdown, the temperature increases 30-40 degrees. Its important to allow the oil and metal cool down slowly. Driving a truck with 21 gages, oil temps for engine oil, tranny and rears, operating temps of engine oil is 250 degrees or so, idling down, at 1,000 rpm with no load for 15 minutes will cool everything, without getting cylinder wash. Oil will cook in the turbo otherwise and destroy the seals and eventually the bearings. Done correctly, the turbo will still be fine after 2.3 million miles.

[@cjgordon22]

Turbo timers is what was once used

[@general1977]

I wonder, how you guys in the US want to generate heat in a turbo anyways (unless you are towing maybe). Greetings from Germany. 😆

[@symmetry08]

In summer longer

[@jonathanrabbitt]

If you're smart about how you approach your destination, you shouldn't have to idle at all. If you can coast most of the way in to your parking location (as in from highway speed and/or downhill) and only use gentle throttle applications (with little or no boost) to finish the job, you shouldn't have to idle. Coasting and changing down to keep the revs highish puts a load of cool air (and no fuel) through the engine and turbine; much more than idling.

[@pauledwards7182]

You should that to every vehicle.

[@jefferysill5539]

Now go price a turbo and labor to replace,

[@theanimeotaku2794]

I mean, it really isn't a big deal I've shut my truck off after like 30 seconds of idling from a long haul but mainly i run the heat full blast which brings down the temp quite a bit honestly if you are about to overheat i almost did 4-5 times lol turn the heat full blast it will bring temps down significantly you dont need to idle that long also idle laws exist....

[@AK_5.9]

The additional engine cooling by running the heater won’t necessarily correlate with EGTs/turbine temperature and the propagation of heat from the turbine to the bearings. This video is about the potential mechanical consequences of recurrent hot shut downs to the turbocharger/turbochargers. The lawfulness or unlawfulness of the idle cooldown is irrelevant to the scope of this video. The information I present here remains true.

[@theanimeotaku2794]

​@AK_5.9 bruh you basically said to idle as long as you think you should with no proof to back up how you should lol and what I said works it basically adds headroom for your engine to dump enough heat to not overheat your engine dumps heat into the oil as well as the coolant you only need to let it idle for 30 seconds or less FOR LONG HEAVY LOADS not normal traffic commutes in a pickup truck maybe if you have a shity air fuel ratio and run really really lean then again spread false info I guess...

[@AK_5.9]

I specifically said I let mine idle three to five minutes if the turbo has been hot. I assumed my viewers would interpret “hot” as driving conditions in which the turbo had reached temperatures higher than those that would be reached during short commutes. This is still what I would recommend if the turbo has been hot to promote its longevity. Journal bearings are typically made of brass which has a relatively high coefficient of thermal expansion. High enough for the thermal distortion to be significant given the bearing bore tolerances within a turbo. Several have posted in the comments that there used to be placards in military and commercial turbocharged vehicles stating the need for three to five minute idle times before shut down. This adds support to my recommendation. Take it or leave it, but this is what I do and what I suggest. I don’t see how I have spread false information here in any way.

[@HR-rt9nh]

i let it idle until i see oil temp come down to 180-185 depending how badly i have to p

[@AK_5.9]

Sounds like a nice objective way to do it 👍

[@mitchellhedrick6061]

I do this on my ecoboost aswell

[@daveturnbull4433]

It’s not so much a “ hot shut down “. You are actually letting the turbo spool / slow down. One you shut the engine of there is no more oil being pumped to the turbo and it is still spinning only being lubricated by the residual oil in the turbo housing. So let your turbo slow down before you shut your engine off because you will smear bearings.

[@cbylsma626]

Waaa? The turbo spools at over 2000 rpm at idle! Residual oil on the bearings will boil and polymerize on a hot bearing leading eventually to failure!

[@daveturnbull4433]

@ that’s why you let the turbo spool down. And yes it aids In cooling

[@Thelegend-z7d]

You should always lube your hot shaft

[@detaart]

absolutely unnecessary with modern liquid cooled turbo chargers

[@AK_5.9]

This has already been addressed multiple times in the comments section here.

[@Gareyindaloops]

A "turban" is a type of headdress worn by males of a certain faith. A turbocharger uses a "turbine". BIG difference.

[@woods840]

Lolololol

[@AK_5.9]

Both pronunciations are perfectly acceptable, correct and widespread.

[@Gareyindaloops]

@@AK_5.9 Perfectly acceptable to who???? You and everyone else that missuses the word. Correct??? Look up the words in a dictionary and try and tell me that they mean the same thing. Widespread???? You are correct there but just because it is used by a lot of people doesn't mean it is the correct use of the word. Even the picture you used had "turbine" on it. If you are going to make videos don't put out misinformation.

[@AK_5.9]

It is perfectly acceptable and in widespread use because it is correct. Look up the word “turbine” in the dictionary, as you suggested, and you will see both pronunciations there. For this reason, that the pronunciation is correct, I am not putting out misinformation.

[@FireBosspilot]

Excuse me….ahh “turbin”??

[@AK_5.9]

Both pronunciations are perfectly acceptable, correct and widespread.

[@GroovesAndLands]

If you never shut it off, you'll never have to ask yourself "how long to idle"

[@jazz230]

On behalf of the majority of the population, no one wants to hear/smell your diesel engine. Takeaway: Unless you REALLY have to, don't buy a diesel.

[@AK_5.9]

Show me the evidence that you were elected as the spokesman for “the majority of the population”.

[@bb8.371]

Keep to yourself unless you're willing to learn how stuff works. You have a lot of pride and zero knowledge.

[@bb8.371]

Keep to yourself unless you're willing to learn how stuff works. You have a lot of pride and zero knowledge.

[@cbylsma626]

Explain why most vehicles in Europe are diesel, including American brand vehicles like Dodge caravan, Ford ranger pickups or GMC suv's! It's not because of smell!

[@randyballew8795]

Gonna straight pipe mine now... just because.

[@SmOgER10]

People out there worrying about pollution and climate warming and meanwhile we have this guy idling his diesel truck doing nothing just so that his turbo could extend its lifespan by a day or so. No offense but I just find it hilarious 🤣🤣

[@AK_5.9]

If you can provide convincing evidence that one will only extend the life of a turbo by “a day or so” with consistent cool down idling vs consistent hot shut downs I might reconsider my position on this.

[@leebuck180]

I recently had to buy a reman turbo to replace the locked up turbo on a diesel tractor that had the engine rebuilt, the reman was ONLY $850.00! modern turbos ARE way more expensive, I have time to let the turbo cool!

[@dirwood4365]

I find it hilarious that the EPA had diesel trucks install DIesel Particulate Filters and 9 times out of 10 the damn regen starts just as I'm about to get home. To protect the stupid DPF I now have to go waste diesel and keep polluting for another 10-15 min drive. Read that again. I have to burn more diesel and create more exhaust to lower pollution. F'ng retards! Either that or spend a couple more thousand for a new DPF. Which do you think the consumer will choose? It's a rhetorical question. Burn more diesel and pollute. For those that say delete. Yes I wish. Ive had to do emissions testing yearly. Hopefully the Gov. gets their head out of their a$ses.

[@jefferysill5539]

I used to idle down 87 Daytona for 3-5 minutes to let turbo oil not coke the turbo bearings, changed oil every 1500 miles, ran Mopar computer brought boost up to 10 psi on 2.2L

[@midas7934]

Yeah i dont think letting it idle a couple minutes will make a big impact to the environment. Diesels are already more efficient than gasoline engines, and if you burn your turbo, the carbon footprint to manufacture a new one and ship it is much worse. Best to just let it cool down when needed, save money, time, and work