I guess that's why I got a million one twenty five out of the original turbo on my 3406E. The only reason I replaced it was because it came with the engine rebuild kit I bought. I am a firm believer in letting the engine cool down before shutting it off. In my opinion this is one of the most important videos on diesel engines ever produced. Thumbs up.

In the Army we had so many problems with the turbos getting coked up from running hard and just shutting off right away.

when you work hard you get sweaty, you dont want to go to bed sweaty so you take some time to relax

This guy should be in a college teaching students how to become Real Diesel mechanic.

When I would shut down in the evening I took it easy on the truck before stopping. After parking it I let it idle during my walk around to cool down. I always loved the guys that reved the engine up and than shut it down. They just spooled the turbo up and than stopped the oil flow to lubricate it. I owned the truck and wasn’t just a steering wheel holder.

Turbo timers work. Even a turbo gas engine needs to spool down. From a retired mopar flat rate dealership tech. I replaced a lot of turbos due this especially the garrets.

FINALLY, someone who could explain the reasons for cool down periods even though it was something I always did on the farm. I've been asked before but no direct answer to give. I felt like the guy in the destruction of the week.😱 Your knowledge at your age is explicit and well appreciated. I can see why you get promoted. Good job!

Turbo timers should be factory install.

Got yourself a new subscriber. 15yrs ago when I was in the rice fields, boss man was big on letting the tractors idle for 8-10 minutes. We worked them hard, small time farmer. Old Versatile had 14,000hrs on it with no major engine repairs when it got sold to South America. My old 12v I let idle for bout 20 seconds or so. But I have a long driveway I idle down in 3rd gear getting to the house. And she ain't my tow pig.

I was always told to let any turbocharged diesel idle for 5-10 minutes after a full day of running the truck and always have. The reason I've always gotten is the turbo and it's shaft bearings will be so hot if you just shut it off it'll actually bake the oil into sludge because it's no longer flowing, just sitting there baking. Glad to see this is actually true.

My engine cool down I made a habit before shut down of engaging the fan with the switch on the dash and let the engine idle for at least 5 to 10 min especially throughout the hot summer days and you explain that very well with the heat that is created via the turbo

I always idle or drive slow for about 10 minutes after driving fast before turning it off.

i forgot what i was driving as a kid i think it was the old Ford 946 our neighbor let us borrow but i remember on the dash it had a warning label that said to let the engine cool down and if the engine stops while under load to try and start it again and let it idle to avoid damage. IMO if its got a turbo it should have a turbo timer better safe then sorry also its handy for hot days and your going in to a servo or corner store for a few mins you can set the timer to its highest setting my one can go up to 10 mins and it keeps the AC running. timers seem to have bean mostly forgotten i have so many people ask why my land cruiser is still running after i get out and walk away I've even had a truckie ask me that do modern truck not come with a turbo timers any more? i remember it being standard.

Great tips here to help no matter what diesel engine you have last much longer. Install a pyrometer if you don't have one...they're engine life savers for letting you know when to dial back when the engine is under heavy load.

If I can help it, I let any engine I use cool down a bit before I shut it off, more so when a turbo is in the mix. My roommate's have had zero turbo issues with their 2011 1.4 turbo Chevrolet Cruze because they, and myself, let the car cool down a bit after the car has been driven. I have seen with my own eyes, just how terrible it is for a turbo to not be cooled down first before shutting off an engine. Saw a lot of dead turbochargers at the VW dealership I worked for, both for gas and diesel engines, because people drive their vehicles hard and shut them off as soon as they get where ever they are going.

One other thing, if you have hot spots that are close to boiling, those areas will scale up if there's any minerals in your cooling system, and if scale buildup occurs then it insulates those areas from the coolant which in turn lets them get hotter and could cause damage. That is also why you don't use tap water to mix with your antifreeze.

Thanks for the explanation!! Several months ago as a newbie, my C7 overheated and stupid me shut it off. Luckily, I took my head out of my *ss and re-started and watched the temp go down. Learned a lot that day and this confirms I got lucky. No major issues thankfully. Great video as always!!

I have two diesel generators, a Kubota and a Deutz. Neither have turbochargers but I have always allowed them to cool down for about three to five minutes after removing the load. It's just the sensible thing to do, and costs only pennies.

Some older Peterbilts have a shutdown timer on them. It was just a timer style timer. You set the timer and instead of a ding, it shut off.

In the early and mid 00s I drove a UD 2600 and the manual said to idle the engine for 2 minutes to let the turbo slow down before shutting down which obviously kills oil flow. We also had a GMC badged Isuzu (both trucks 26K lbs GVRW) with the Cat 3126 and I figured the same principle applied so I did the same with it, and I explained this to my supervisor and he instructed all the other drivers to do the same.

The manual for my '02 Super Duty specifically recommends idling for at least three minutes after running under a load. I had a Turbo Saver installed when I first bought her and have always used it. I always let my Powersroke idle til my EGT drops to 350 or a bit less. I like to think that and using T6 Rotella have helped avoid coking and turbo failure for the 21 years and 278k miles she has in her. The Turbo Saver lets me set idle time from 1 to 13 minutes. Works great.

All correct and explained very well what I can add to what you are saying that operators standing waiting with a stopwatch waiting to cool of for a given amount of time seldom works. But a bit of forward thinking and change of behaviour can also give equal rewards . For argument sake racing up a highway straight into to park then standing and waiting can make an operator impatient and just shutoff the engine. Or simply ease of early on the throttle pedal before arriving at a rest area and steadily negotiating your way into a parking area has dual rewards of being able to arrive and park safely and also adds to your cooling of your engine. As I try to explain to machine operators when bringing a machine back to the compound run the machine back in shut the throttle down and park carefully then set to idle put your helmet and jacket on roll a cigarette then before you get out of the cad shut the engine down. I find I have better success trying to change behaviour than just telling some body to sit and wait as some guys will but most won’t. Great videos and great content best of luck for the future.

The engine also has static heat. My 6.7 cummins heats up from 195 to 210 just sitting after shutdown

Newer Mack trucks if engine is hot will not turn off the engine until it cools itself down. Meaning you can turn the key off yet the truck will remain running until computer turns it off. Usually within 5 to 10 minutes.

Good topic. This also applies to ANY equipment with a turbocharger (needs an idle cool-down), but it's also a good idea to shut down electrical loads in the last few minutes on any vehicle to let the battery recover, and let the A/C system normalize, so condensation doesn't form in the ducts after you shut it down.

I always idle my turbo diesel car/SUVs for 2 mins before shut down. Good practice for longevity

What I would like to see is a three part series. Explaining to your audience Hydro-mechanical timing advance and how it works and why you leave those screws alone up front. Mechanical governors and how they work. Lastly the main fuel pump on a NSFS and how it works, and the importance of those little clamps and brackets on those fuel injection lines.

Cool down makes sense.... When I'm towing with the Dodge, there's a pass I often go over with a nice place at the top to stop n pee. The thought of oil n coolant not moving through a smoking hot engine n turbo was not to be considered. Plus, I kind of dig how well the truck tows and run at a nice clip, watching boost and other gauges, enjoying the engine take it like a boss.

I totally agree with this. It is somewhat confusing in a highway engine due to the fact that some engines actually have a lower coolant temperature while driving. If you notice your fan will kick on at say 210 and you tool down the road at maybe 190. You pull in to the yard and idle and your temp gauge actually rises. This has been a discussion of mine with operators that just shut down. So the way I word it is to let temps stabilize and if you have a pyro let it fall off. Tell guys why they should warm up is a totally different argument. I tell them that being a mechanic helps me understand and see in my mind all the things inside an engine that can go wrong. You sure can tell the difference between someone that knows and don't know when you start breaking into an engine

Basically when the engine is shut down all lube and cooling stops apart from the ability of coolant to superheat around the valves which is very effective at cooling actually. Yes it can eventually cause cavitation/errosion. Turbo on a hot sudden;y stopped engine keeps turning for about 30 seconds, effectively without lube and when it does stop the extreme heat may well bake and caramelise as you indicate. I've seen abused engines in motorway/highway truck stops start boiling out of the coolant expansion tank cap, starting up to two minutes after the abusive stop without cooling from highway loads. Thermal stress on rapidly contracting components such as exhaust manifolds and heads/head gaskets can cause fairly rapid and severe damage as well. As a rule of thumb a hot engine under load should only ever be shut down suddenly for one reason. That is when the oil pressure warning light comes on. It then becomes an issue of damage limitation. A sudden engine stop is likely to cause less damage than running the engine for a few seconds longer to allow it to cool down. A few seconds running with no oil pressure will undoubtedly cause a major overhaul at best. At worse, a rod out the side.

progress rail needs to follow CAT's advise. the model SD70 locomotives have auto shutdown to "save fuel" that shutdown the prime mover only 30 seconds after the unit on the train has stopped no matter how hard it had been running! of course this keeps the turbo company in big money.

I was pulling a heavy load with a gasoline engine and the temp gauge was reading normal to a little high. When I stopped for fuel and shut the engine off, I could hear gurgling in the overflow tank. I checked the temp gauge and now it was pegged to the hot side. I immediately restarted the engine to get the coolant and oil circulating again and it moved back to the needle went back to the middle/normal position. After that experience, I never shut down an engine if it has been working hard. I give it a few minutes to vent off excess heat.

Im glad I saw this. I always cool down the engine. I was told turbos go out around 700k to 800k.I had C15 NSX, original turbos started to leak oil at exactly a million miles. I always took my truck to Cat, I never would let Freightliner touch my engine, the tech at Cat almost fell backwards when I told him the truck had original turbos. I never babied my truck she was always running 70-75. Take you for your information!

While running a Cummins L9 doing highway duty for a heavy RV, I will let it cool down between 3-5 minutes before shutdown (Cummins recommendation) . You can actually watch the temp gauge decrease in temps. Never be in a hurry to destroy your engine.

YES...helps avoid heat soaking the oil to turbo bearings and other critical components.

This is exactly why I'm becoming a diesel mechanic before getting on the road in a big truck. I heard about a guy quoted $20,000 for an engine repair and he was actually considering doing it! That time and money is much better spent learning the trade before getting on the road. It's a safety issue for you, other drivers, and also the people you're delivering goods for as well. If we don't know the condition of our rig, how the hell can we guarantee that it's going to reach it's destination??

First the Goat was wonderful. I shut my 3406E down only after the pyro gets to 300 never before. Keep up the great work I enjoy your videos

All new cat machines have a engine delayed shutdown after hard load so this makes perfect sense , amazing video I enjoy watching your videos sir

Greetings from the Philippines. My car is a Mitsubishi equipped with a 4N15 Turbodiesel engine. I always idle the engine for about 2 - 3 minutes before shutdown, especially after highway driving. I also change the engine oil every 6 months or 5,000 kms. Thank you for the information concerning engine cooldown before shutdown.

For a typical trucker, this is easier than it sounds. I monitor EGT, coolant temperature, water temperature and transmission fluid temperatures electronically. In summer heat when I've been pulling heavy or large wind resistance loads is when my temperatures are the highest. Just idling while fueling for 10 - 15 minutes and my temps are back to normal. So when a truck slowly makes it's way into a truck stop, finds a parking spot and jockeys into position, the engine is barely working the whole time and by time you set your brakes and log yourself on duty to do your post trip inspection your temps are pretty much cooled down to normal. Me personally, I like to fuel up before shutting it down for the night but that depends on the fuel aisle and parking situation also. Point being, you won't have to idle very long after parking. Maybe by time you check your lights, tires, load and look for leaks on the engine you can shut it down.

Let the temp even-out as much as realistically possible, avoid hot spots, thats the idea.

Thanks -Nicely done Josh well presented & explained . Down here in Southwest TX. heat is a much bigger factor than the cold . I tend to "high idle" ( 700-1000 rpm) my Cats for 15 to 20 minutes then slow idle 400-500 rpm for another 3-5 minutes . This is on a day w/ ambient air temperature @ or above 110 degrees & heavy loaded .

Now you have 175,AND1 subscribers, on a more serious note. Good down to earth explanation of what we should do to cool the engine down at the end of a haul...

Even on new diesel engines in a 2500 or 3500, after my 10 mile test drive, I let it idle for a few minutes to let them cool down a bit. Same with turbo gas engines, it allows the coolant to go through the turbo(s) to allow them to cool down.

Exactly! What Josh said! Shame is, newer trucks don't have the guages to monitor all these temps. That's why I had a 96 Pete 379. Thx for the videos. Good job

A pyrometer is very useful for judging when to let the engine cool down.I always found that letting the truck coast to a stop and running in low range to find a parking spot was sufficient.

Thats why the big diesel engines in trains and ships have pumps that run oil through the turbo for 30 minutes after shutdown

I started doing this with my 5.9 Cummins after high speeds or loaded trips and I’ve noticed the difference. Engine does run smoother and feels more confident when I let it “cool” down

Been trying to teach why you let them idle before shutdown and the new blood thinks I’m crazy also tried to tell them in summer moths when they have a hot running engine to let it idle to bring the temp down of course I’m crazy. They don’t understand how a diesel works that’s why the new blood don’t get it

Number 1 on the list speaks to intake air with corrosive contents. I just think about the clowns with big sport fish boats. They run them wide open out to a fishing spot then shut the engines down and drift. Then they bitch that the turbos are junk when the salt air and heat trashes them out prematurely. Great video as always.

Ive always practice this, get the temp down to idling temperature before shutting down.

Been a trucker for over 20 years....my grandfather was a diesel mechanic so I was told...15 minutes to cool off and about 45 minutes to an hour for warm up....and I haven't ruined an engine yet for cavitation or turbos going out ...knock on wood

same for some gas engines too. once i shut off my 95 f150 i6 after a long pull up a hill, started getting hot and missed for a few seconds after restarting.

Get off the motorway, get parked, finish swearing, stretch. look at all gauges blankly, collect bits and bobs, write down whatever you have to, sit back and relax for a moment, guess how long you’ve been parked, give it a minute for luck, turn off engine. When I was young that meant pull up the stop button, again and again ! it was amazing how many stop buttons got hurled out of lorry windows.

Yes it needs to cool down, the red hot turbo needs cool oil to cool It down otherwise it will carbonise the oil left sitting in the turbo when it is shut off straight away without cooling, you should always warm a turbo Diesel engine too. I always put the cabin blower on full hot for 3-5 minutes before shutting off to draw out some heat..

When I'm a few minutes from my destination and I know I'll be shutting the engine off I try to run the fan in manual mode and I'll stay a half/full gear down where I would normally be. This typically gets me pretty close to the base idle temperature for coolant and oil without having to idle much at all.

As a farmer I let them cool down but with our semi's during harvest we don't have time to let it cool down as we have to get out of one truck and directly into another truck. However it's not like we are working them really hard like a tractor or combine

Always a great Presentation, thanks !

Very interesting. We live in Idaho. So we get a bit of North Dakota (for like 10min a year) and a bit of Arizona for a tad longer. This was very helpful!

Love your spin on diesel engines

When I was just a lad 40 years ago, things were explained to me just prior to, or just after I got smacked in the back of my head for doing something stupid. Shutting a motor down, gas or diesel, just after I’d ran it hard, would earn me a serious training seminar.

So I guess when I pull off of the highway and screw around getting to a camp site or to my storage place I've probably done enough low load running where the engine should be cooled down, but I'll make sure and check. Keep the good stuff coming.

Josh that was a good find on the turbo, you know within a few days the turbo may have went out and they would’ve tried to blame that on the overhead work.

Hey can you explain why some bolts use washers and some don't on engines. thanks

I had a 93 Dodge/Cummins for 20 years. I set the pyrometer probe after the turbo which will always read cooler than pre-turbo. It never hit more than 750d under load and my practice was to let it cool to 300d before shutdown. I now have a 2012 RAM/Cummins and set the pyrometer probe post turbo. It reads well over 1000d just pulling a grade unloaded. I couldn’t find any shutdown information and so settled on 400d. I can tell you from years of experience running these trucks as well as diesel boats that you can idle them till the cows come home and you won’t get much of a reading on the pyrometer and the coolant isn’t much quicker. The engine needs a load for both the exhaust gas and coolant temperatures to rise. A Cummins engineer told me fire the engines up and idle out of the harbor than gradually bring up the speed. Going back in under idle will cool everything off just fine.

Turbo charger failure was a big problem in the little Chrysler 2.2L engine from the 80s for this very reason. They were great engines even when you pushed them too the limit,but you had to take care of them.

I drive, but it doesn't have a kitty kitty, I grew up around heavy equipment & my dad thought me this back in the late 70's - early 80's.I run lowboy & load my self, even after getting it on lowboy, I set the brake & let it idle to cool down as I'm tying it down then shut it off.When I get back to shop ,I let it idle to cool it as I'm fueling up & after I actually park it. As I'm doing my walk around checking things out then checking temperature, if it's down I shut it down.

I've read owners manuals for 50s era Cat tractors many of that era weren't turboed manual recommends a cool down time the idea was to let the engine normalize.

Military taught us to let the engines rest at the end, after a hard run.

my dad taught me 400 years ago to avoid hotspots inside the engine just like you’re saying idle down for three minutes to avoid hotspots. So I’d do a post trip walk around bump tires er clean tracks look for leaks and three minutes went by quickly. Damn good advice. and funny 😄 in spots.

Great information from a great caterpillar expert 👏

Thanks for another one!!! Still laughing from the scream🤪👍🤟

Good video. I always knew to let the engine cool for 5 minutes because during my cdl driving test the instructor got on me for shutting down immediately and explained how scalding hot the turbo is and how the oil will leave a residue on the bearings. I use that 5 minutes to do paperwork and or fuel the truck for the next day. Depending on if I'm over the road or local. 5 minutes is a blink in trucking.

The main reason to not shut a turbo diesel down after heavy or highway use is because the turbo can keep spinning at high speeds for upto a minute which causes shaft and bearing wear when its oil supply is cut off.. idling an engine down helps bring the turbo speed down with correct lubrication.

Ahhhh, all this talk made me remember when turbo timers were considered A MUST HAVE on EVERY turbocharged engine when engine control systems where still in their infancy and engine oil was made out of cat's piss and protected like wise, even the synthetic ones. I feel old now. 😔

The inlet end of the turbo shaft is frozen from air being vacuumed near it. The heat transfer from the hot side to the cold side of the turbo shaft is significant.

I've always been taught to high idle at 1000 rpm for 4 minutes then idle for a minute before shutting down. What's your thoughts on this? Been told its to ensure good flow to cool everything off

It's in a freightliner owner manual. Let it idle couple or 3 minutes before turning it off. Often I see the temperature gauge drop 8 to 15 degrees/ oil gets to circulate and cool down and not cook the engine. I even apply it to all semi trucks I been driving since I read that

As always great information thank you! 👍

Glad I found this. I’m new to the trucking game and came from being a gas tech. I would have never known to do this. Luckily I’ve only put 30k on my truck since I’ve got it. Sitting at 180k

We had a 600KW cat genset that we used to run our grain dryer. It had one speed wide open. Always felt bad shutting down a screaming engine at night. Usually had at least 10 to 20 minutes of light to no load as I shut off fans.

If the engine is running full power the exhaust temp is +/- 480 degrees Celcius, When you stop the engine directly, the tensions in the metal is enorm. (head vs block) if you let it cool down till a mild 130 degrees Celcius, the difference between the collant is a mild 50 degrees (80 degrees for the coolant and 130 for the exhaust = +/- 50 degrees Celcius) Compare this with full load 480 degrees Celcius exhaust with 80 degrees Celcius collant = +/-400 degrees Celcius. Metal expands more @ 480 degrees temp then with 130 degrees

Great video👍 I always wished I could get my guys to understand this when I was still doing construction work

I agree you should be a teacher to make better mechanics.

Love your vids keep em comming

it was all the rage a few years ago to fit timers to your turbo diesel 4wd, so it would continue to idle for a few minutes after you turned the key off.

My coworker owns an ol powerstroke, I own an ol duramax. I warm up and diesel down, he doesn't and is on his 3rd motor, 4th turbo. I'm still going on the same motor n turbo it came with. Take care of your diesel truck.

Let's see...cold starts, hot shutdowns, Heui pumps, exhaust gas temps...maybe I should have been taking notes. Another great video from the master of Cats.

Yeah but in over the road truck engine by the time you pull into a truck stop and back in you only need one minute more idle

If you’ve been going up on a steep grade for a mile or more, you don’t want to shut down the engine right after the grade. The water temperature will continue moving up and getting cooled by the fan for the next 15 minutes or so after the upgrade. If you don’t do this and shut off the engine right after a steep upgrade, you’ll notice that the water temperature is maxed out on the gauge next time you turn on your engine. This can damage gaskets, o-rings, hoses, etc.

Mostly for the oil galleys in the turbo because under load the turbo is red hot.

idle for a few minutes, remember if you're coasting to a stop that time counts. But not half an hour like some guys do. Also how hard has it been working? A big engine hauling low weights as is common in the US means it's not working that hard anyway.

Your videos should be included along with all the safety and diversity videos some of us have to complete at work. Some guys just don’t know the basics even though they’ve been driving a long time.

I have a Cummins 6.7 350 turbo you have to let it idle 7 minutes. Due to the fact that the turbo is still spinning and it has to have oil to the turbo bearing so it won't seize up the turbo. Also cummins has a wet liner idling also cools down the liners. Oil removes up to 80% of engine heat so iding helps cool the engine as well. Cummins engine warranty says you must idle for no less than 7 minutes minimum. When you take it in for service this is checked.

Thank you! Good advise!

I always do. I run it for 5 minutes to let circulating oil cool the turbocharger shaft.

I always let them cool down before turning it off not only can you hurt the turbo but you can create alot of heat spots in the block and head

A decent number of trucks use the fuel to also cool the injection pumps and control circuitry on said pumps (like the 24v cummins).

I thought it was common knowledge to allow your engine to cool down,,, especially when it was loaded. Thanks

Yes this is a big issue in automotive engines, too. The combination of long change intervals and oils with reduced shear stability like 5W30 or 5W20 etc. and not letting engines cool down. The oil gets too hot around the turbo because it doesn't move anymore after engine shutdown and burns up. In most of those cases the turbos fail because of lack of oil supply. I've seen banjo bolts from the turbo oil supply line that were completely clogged with burned oil/carbon buildup. I've had a customer with an Audi that repeatedly destroyed turbo after turbo on his car in as little as 20,000mls. Some manufacturers have now additional electric water and oil pumps that keep running after engine shutdown to minimize this problem.