How long to idle a diesel motor?

[rpk]

Cat 3126B has a "Fast Idle" switch to prevent fuel slobber.

[spinn]

I was talking to an OTR truck driver at a Flying J a month or so ago, he was telling me that some of the rental fleet tractors will no idle for only 3 minutes before the auto shutdown

[tbbg II]

Originally Posted by Pa Miller

Get a ekg temp gauge and when it gets below 300 degrees shut it off...or turn on the high idle switch .

That will also allow you to check the heart beat of your diesel. A simple eg gage will check the exhaust temperature. These can be be tricky to install as you need to drill a hole in the post turbo manifold and you certainly do not want drill filings to get into the turbo...

[CarlGeo]

When stopping after high speed highway driving, the primary need for a cool down is for the turbo charger to cool down. Those turbines spin at extremely high rpm's and generate considerable heat, and need a few, 3 to 5 minutes to cool down before stopping the engine.

[Pa Miller]

Gauges are worth the money , hard to guess when it's down to below 300 degrees ..

[Ray,IN]

My Cummins owners manual states simply pulling off a freeway onto the off-ramp, then sitting at the stoplight/stop sign, is usually enough cool-down time. No interstate or mountain driving? No cool-down time required.

Many states now have idling laws which impose strict limits_and fines.
What you should know about bus engine idling, by the EPA

[stan5711]

What about the winter time,do you start the coach or Gen every now and then to keep things lubed up.I thought you were suppose to the gen once a month.

[Pa Miller]

Yep you need to exercise the gen every month run it under a good load too.... if you don't you will pay for not doing it.... lol

[Mr_D]

Originally Posted by speed racer

After coming off the highway it's a good idea to let the engine idle for a few minutes to let the turbo cool down. It is lubricated by the engine oil and if you shut it down right away the heat from the turbo will turn the lube oil to a sludge and in time will destroy the turbo from lack of lubrication.

Direct from Cummins:

Idling at Startup or Shutdown

At Startup
– Idling for engine warm-up is not required
– Once oil pressure is seen … put motorhome in motion
– Don’t operate at full road speed until engine temp reaches approximately 150 deg.F.

At Shutdown … Idle (3-5 min) required only after full throttle/high power operation.

Idling is not necessary after normal operation such as exiting highway, driving into rest stop, campground, etc.

[Mr_D]

Originally Posted by CarlGeo

When stopping after high speed highway driving, the primary need for a cool down is for the turbo charger to cool down. Those turbines spin at extremely high rpm's and generate considerable heat, and need a few, 3 to 5 minutes to cool down before stopping the engine.

See post above for correct Cummins info.

[Pa Miller]

Yeah well cummins sells parts too!!! LOL buy a gauge

[ChasA]

Well, there is always someone who thinks they know more than the manufacturer. And despite the documentation they are right. Watcha gonna do?

[Ray,IN]

Originally Posted by Pa Miller

Yep you need to exercise the gen every month run it under a good load too.... if you don't you will pay for not doing it.... lol

A diesel engine will never reach normal operating temperature while idling. The coach engine should only be started when you are going to drive for at least 20-30 minutes, which is enough time to reach operating temp. The genset, according to Onan, should be ran at 1/2 load or more for 2 hrs. per month.

[Duoglide1]

It's my understanding that you're not running the generator under load monthly for the sake of the engine-it's to dry the windings in the electrical generation part of the unit. Running your big diesel even at high idle does no good as it cannot achieve full operating temperature without a load on it. Also you are contributing to condensation in the oil pan. YMMV


2007 Monaco Executive 45' 525 ISX