gallons per idle hour?

Most of the time its actually less than 1 gallon per hour. No hard data other than I am the one that buys and pays for fuel.

 

We used to have a driver that would stay at the Hook 30 miles from his house and idle over night because he said he didn't want to wake everyone up when he got home. His "thoughtfulness" cost ~$40/night.

 

Yep...any idle speed much lower than 1000rpm's does not keep enough oil moving to lubricate the turbo bearings.

 

really?. Bearing on my N14 was still fine at 950k when I sold my old truck, I replaced turbo on ISX at 800k and not due to bearing going bad. And when I idle its 600 rpm. As far as fuel used display on my Volvo shows .5 g/h at low idle and .8 on high idle

 

So... figure on 0.8 g/h, a 10 hour break every day, and 51 weeks per year, 6 days per week... that's 2448 gallons of fuel every year. Take your own fuel price, but I'll use $4/gallon - that's $9792.00 per year - every year to idle. Kinda makes that APU look a little more affordable.

 

Ive only had ISXs. Dash readout went between .5 and .8 gph.

 

Really? 10 hrs every day? Really
As far as your numbers go its very convincing...except for one tiny thing. Correct me if I'm wrong, but I belive that diesel powered APU's use ( burn ) diesel. Number of .3 g/hr comes to mind. So using your high number of .8 g/hr you save .5g/hr. Its $ 2. Assuming 2000 hrs idled a year that's 4k savings. I don't know how much routine maintenance will run you but it got to be at least 500 a year. So you'll save about 3500 a year. Since new APU will run you north of 10k we talking 3 years till break even point. And that's without a penny for repairs. How likely is that?. So run that no brained part by me again, cause I don't get it.

 

It is also said that one hour of idle is equal too 100mi of driving. Ive heard this from many mechanics and on a lot of trucking radio. So other than paying for fuel you also have to change oil sooner and put un compensated wear on your engine.