Why do class A's run engine when leaving RV Park at site?

Because some diesel owners like to increase engine wear. Idling a diesel will not bring the engine up to full temperature, so idling for extended periods of time puts extra wear on the cold engine.

NO diesel needs to be run more than a couple of minutes to bring the air up and everything else should be done while hooked to shore power. ALL manufacturers state that the short distance from the CG parking spot to the highway is all the "warmup" that a diesel needs.

I've heard them idle, but rarely 20 minutes. Wow. My Cummins would start regenerating in that time, and you don't wanna be around that!

I've been known to not turn mine off once it's running - for instance, to leave the site and dump. It takes a long time to heat up 15 gallons of oil. Heck, sometimes I don't even turn if off when fueling. Truckers do that too.

No, I don't have a Class A, but no matter, it's still a diesel with air.

What I don't understand is why OTR trucks idle them ALL NIGHT, when it's not cold or too hot outside.

I bring in the slides and then the levelers all on shore power. In fact, if I turn the ignition key to start the engine I get a loud alarm on the levelers if they are deployed. After I have accomplished the above and disconected everything I then start the generator for my refridgerator and a/c units. Then I start the engine to inflate the air bags and build up pressure for the air brakes. Once they are ready I'm GONE.

I run mine while the jacks come up, then we are gone. Maybe 3 minutes.

Some folks were taught and still are "old school".

About 90% of all class "A" have air brake systems that have to be filled by the air compressor on the motor first off, then like mine the motor HAS to be running before I can activate the coach leveling system to both level and retract the hydraulic levelers. Also running the slides in requires a good amount of power so once again the motor needs to be running for this too. Believe me most of use do not like to run our motors at an idle any more then we absolutely must due to the exhaust regeneration system used to capture the exhaust soot.

Monty-Rob wrote:
I wondered why most class A's run their engine for 20 minutes+ when leaving their site and are hooked up or could remain hooked up to electric?

They have a severe case of "Recto-cranial inversion". I hope it only seems like most and is really only a few. If a diesel they only have to idle long enough to built up air pressure, which on high idle is a couple of minutes at most. If a gas coach no longer than a pickup truck.

Personally, I love the smell of Napalm, I mean diesel in the morning.

Gas powered coaches do not have to do this.

To build air pressure for brakes and to inflate air bags.

Usually dont need more than 5 minutes.

Bill