Community Forums

b1rider · 05-19-2023, 06:43 PM

When you pull into a rest area or stop to refuel, how long do you let the motor idle before turning off? I always want to let it idle a bit to cool the turbocharger, the question, how long?

While I’m asking, how long do you let the diesel warm up before driving?

daveh5525 · 05-19-2023, 07:18 PM

good topic.
I shut down as soon as we stop. I build air, check gages, check ride height, verify oil pressure, put seat belt on, then go.

**Lt Dan** · 05-19-2023, 07:47 PM

Usually by the time you have idled into a parking area it's cooled down enough and then no more than a couple of minutes. As for warmup, I'll idle long enough to bring the slides in, jacks and air up then ease out slowly until temps get above 160.

Old-Biscuit · 05-19-2023, 08:31 PM

I have pre-turbo temp probe
Coming off Interstate the exhaust temp drops to 600 degrees
After pulling in I wait until temp drops to 350*F
That takes maybe 2-3 minutes

As for warming up engine...start it, get ready to go....then go
Easy on the throttle

It ain't grandpas old diesel

b1rider · 05-19-2023, 08:33 PM

Quote:

Originally Posted by Old-Biscuit

I have pre-turbo temp probe
Coming off Interstate the exhaust temp drops to 600 degrees
After pulling in I wait until temp drops to 350*F
That takes maybe 2-3 minutes

As for warming up engine...start it, get ready to go....then go
Easy on the throttle

It ain't grandpas old diesel

Thanks. It’s what I have been doing.

Old Scout · 05-19-2023, 08:53 PM

PS--perhaps Cummins' past issues with ISC and ISL cracked exhaust manifolds has abated. Assuming these manifolds only have a finite number of heat and cool cycles, I only shut-down when I plan to be parked for a while, eg, for lunch at a rest stop, or at the end-of-day stop. Otherwise, I leave the engine run, eg, short breaks, or during fuel stops.

Toribk · 05-20-2023, 04:10 AM

That's the benefit of having an engine monitoring software.

You can wait (and watch) until your intake manifold temperature reaches the normal range before shutting down after coming off highway speeds for a considerable amount of time.

wildtoad · 05-20-2023, 05:19 AM

Quote:

Originally Posted by Lt Dan

Usually by the time you have idled into a parking area it's cooled down enough and then no more than a couple of minutes. As for warmup, I'll idle long enough to bring the slides in, jacks and air up then ease out slowly until temps get above 160.

I don’t have a diesel but do have to listen to those that do. These sound like a very good procedure. Thanks.

petrel · 05-20-2023, 06:00 AM

As little as possible. No more than a minute or two, or just enough to make air pressure. Like Wildtoad said, nobody wants to hear it.

jrs · 05-20-2023, 03:42 PM

For what it's worth, I had an experienced diesel mechanic tell me the worst thing you can do to diesel's with the new emission/DEF systems is to idle them. If you need to idle, put it into fast idle.

bigb56 · 05-20-2023, 03:53 PM

Quote:

Originally Posted by jrs

For what it's worth, I had an experienced diesel mechanic tell me the worst thing you can do to diesel's with the new emission/DEF systems is to idle them. If you need to idle, put it into fast idle.

This is true but we are not talking about extended idling, just a few minutes for cool down. Shutting down a hot turbo can cause more harm than a few minutes of idling after a long highway run, IMHO. I never shut any engine down immediately after pulling off the highway, even your transmission can suffer from heat soak. Besides that, a few minutes of idling on a modern diesel will be more than compensated for on the next highway run.
If you want to run the engine for extended periods for something like the AC then yes, you need a high speed idle controller.

Soppy · 05-20-2023, 04:40 PM

Normally after pulling off the highway , I will let mine Idle for 30 seconds or so , especially if you are off the throttle slowing down. When starting up, in summer temps, I will let it run for 30 seconds and then gradually increase the speed and load. For my heavy equipment, or generators under load , I will let them idle for a couple of minutes to cool down. I've been using this procedure for 50 yrs with no problems.

Randy125 · 05-21-2023, 07:27 AM

When I break camp I start engine and then unplug and store shore power, then slowly start moving . I’m not a metallurgist but I feel that if an internal combustion engine is warmed up slowly the better it is on the engine. When shutting down I usually idle for about 5 minutes, which usually includes driving from the highway environment.

Nwcid · 05-21-2023, 07:46 AM

I am in a 2014 Volvo and for me it depends.

I rarely shut off when fueling anymore. I fuel up, wash windows while fueling and then move out of the way. If we are going to stay in that location for more than a few minutes I will shut off, but also depends on if I want to keep the heating/cooling running.

But as others have said, by the time you are done with "driving" and are just moving around in parking lots your temperature should be fine.

For starting if it is cold I will often start my APU roughly an hour ahead of time to heat the engine block. Otherwise I typically run it 5-10 min before moving. If my truck has not sufficiently warmed up, my engine brake will not work.