Unrealistic 5-minute idle "rule"

[CRutledge]

I agree wiht you DZink24; I'm in Houston and I can sit in traffic longer than 5 minutes just idling and I am not about to turn my truck on and off everytime 5minutes is up.

 

[DZink24]

Nope... ... ... That is completely different. Sorry



Bob

But. . On my '04 48RE, I didn't have the ability to manually adjust the idle with the cruise control buttons until I had a test run with a smarty at a meet and greet. Now I can do either!

 

[DWeiler]

Wonder if this applies to all or just the Cummins cause my company Ford diesel has been idling sometimes all day in the cold weather off and on for the past 5+ years. Now it does kick up to 1100RPM on real cold days but in the average weather it idles at 670RPM. I have never had to change the injectors or glow plugs yet---mileage to date is 311000+Km. We do load these trucks down day after day with bread/bagels/wraps etc----so we are working them. I do drive mine hard and cruising highway RPM is around 2600 at 75MPH----maybe i blow all the carbon out each day from working it so hard----just a thought. ---PS it is getting tired though(uses3-4 quarts of oil between changes) and is under-powered

 

[TBartlett1]

I worked in a lab with Cummins powered test cells for transmission testing. When I started there they would run the engines at full power and when thru with the test immediately shut them down. If you went to restart them within 2 minutes they would crank over very slow because the pistons would start to seize in the bores and they lost several engines to scored pistons/cylinders. A mandatory 5 minute idle was implemented to allow the engine/turbo to cool and normalize which eliminated the piston scouring. This also allows the turbo to cool which would be cherry red.

I idle 5 minutes only if I’m working my truck under heavy load.

Idleing over 5 minutes will not harm a hot/warm engine. A diesel generates very little heat when idleing in cool weather and in very cold weather can cool to the point where condensation formes in the engine and valves stick in the guides.