Engine/idle hours

willsep · January 25, 2022

Are idle hours included in engine total hours?

I have total of 867.6 and Idle 123.2, does this make it 990.8 total engine hrs? or is the total 867.6 which include the idle hours?

redwngr · January 26, 2022

If you sit in the truck and let it idle for 6 minutes (0.1 hours) you'll know for sure.

I expect the total to include idling -- but haven't done the 6 minute thing while the hours page was displayed.

Kilgore Trout · January 26, 2022

If Idle Hours are not included in Total Hours, somebody at GM is functionally illiterate.

gemarsh · January 26, 2022

And just how do you get Idle Hours to display?

I only see Hours. Doesn't list total or idle.

willsep · January 27, 2022

In the DIC Information screen scroll down until you see Engine and Idle hours

elcamino · January 27, 2022

Total means ALL hours....

You have roughly 4,500 more mile on the engine than the odometer shows.

gemarsh · January 27, 2022

1 hour ago, willsep said:

In the DIC Information screen scroll down until you see Engine and Idle hours

It must be a Chevy or Denali thing. On a '21 1500 and a '22 3500 GMC's Denali screen, it just shows a engine icon and hours...

bdallas · January 27, 2022

7 hours ago, gemarsh said:

It must be a Chevy or Denali thing. On a '21 1500 and a '22 3500 GMC's Denali screen, it just shows a engine icon and hours...

I don't have the Idle hours either... 21 Silverado RST

willsep · January 28, 2022

My is 2020 Sierra 1500 3.0 diesel. And just a quick question to elcamino, How did you figure 4500 extra miles? I am just curious, thanks.

redwngr · January 28, 2022

2 hours ago, willsep said:

My is 2020 Sierra 1500 3.0 diesel. And just a quick question to elcamino, How did you figure 4500 extra miles? I am just curious, thanks.

Lots of machines get maintenance done based on hours -- even though miles is more common on road vehicles.

Anyway, it's sometimes useful to compare the methods.

Your truck has 32,264 miles.

Since both hourmeters are available, we know that driving time is 868 - 123 = 745 hours.

Avg miles per hour = 32264 / 745 = 43.3 mpg

If the idling time was at the same rate -- 43.3 x 123 = 5326 additional miles.

el camino calculated using total hours, so used 32264 / 868 = 37 mph

37 miles/hour x 123 hour = 4570 miles

(and of course, if total is the only thing that is available -- then we use total mile / total time )

Of course, we all realize that there has to be some idling time (-warm-up, stop lights, etc etc) and that all driving is not at freeway speed.

Leads us to what is the 'normal' average vehicle speed.

For some reason I seem to think that typical average speed (base on total hours) is somewhere in the mid 30's.

If the total hours is the only thing that is available -- then then our only option is to compare the average speed with typical average speeds for the same vehicle type. Imperfect method, but can give a little insight into how it is being used.

The was a bulletin or info sheet or tech sheet gm put out that did give an average speed to use with the idling hours - to add to odo miles for service purposes. It also said that for warranty odo mileage should still be used.

an example:

The forklift has 6500 hours -- how does that compare to my pickup?

6,500 hr x 37 mile/hr = 240,500 miles

Edited January 28, 2022 by redwngr

willsep · January 28, 2022

Thanks redwngr, that was a great explanation, and I really appreciate your knowledge and time on the issue.

newdude · January 28, 2022

On 1/25/2022 at 4:14 PM, willsep said:

Are idle hours included in engine total hours?

I have total of 867.6 and Idle 123.2, does this make it 990.8 total engine hrs? or is the total 867.6 which include the idle hours?

Total is total. Of the 867.6hrs, 123.2 of those has been idling.

GM's calculation (formula applies to gas and diesel): The Diesel Exhaust System and DPF Soot Accumulation – TechLink (gm-techlink.com)

"Vehicle Idling

Some vehicles may spend a lot of time idling. Use the following steps to aid in determining the equivalent mileage (kilometers):

Record the total engine hours indicated on the DIC.

Multiply the engine hours by 33 miles or 53 km. This represents an average speed of 33 MPH or 53 KM/H.

The result should be close to or lower than the mileage on the odometer.

For example, if a vehicle has 1812.3 engine hours and 60,837 miles (97,908 km) on the odometer, the engine run time would equate to about 59,806 miles (96,052 km) (1812.3 X 33 = 59,806) (1812.3 X 53 = 96,052).

Since the calculated mileage is less than the actual mileage, the vehicle does not spend an excessive amount of time idling.

If the calculated mileage is more than the actual mileage, the vehicle would be considered a vehicle that idles a lot and this information may be useful in diagnosing any issues."

867.6hrs x 33mph = 28,630.8mi. Per your odometer at 32264mi, Your truck has "traveled" 3,633.2mi more than the engine has physically been running.

If you applied this formula to your idle hours, 123.2hrs x 33mph, your engine has had 4065.6mi worth of idling on it, therefore 24,565.2mi of driving time, totaling 28630.8mi.

So you'd be a low idler.