pm's - engine hours versus miles?
 

Does anyone schedule their engine maintenance based upon hours instead of miles? I'm thinking about doing this. I have a Mack, and the operator's manual gives me the option of changing the oil every seven-hundred hours of use instead of going by miles driven. I'd still grease the truck using miles, though, since technically I could put hundreds of hours on the engine and not move the truck an inch.

When I was working for a farm or ranch, I'd use an hourly maintenance schedule on the farm tractors, but my service intervals weren't even close to seven-hundred hours! I'd grease every fifty hours and change the oil and filter every one hundred-fifty hours, with an air filter if needed, and I'd go few and far between on the fuel filters and hydraulic filters.

Re: pm's - engine hours versus miles?
 

I always do! I believe it's more appropriate, cause idling puts even more "dirt" in the oil. I also keep track of my miles, but just for informational purpose.

Before reading this board, I thought everybody went by hours....

500 hr's max, the new engines load the oil with soot, maybe less hour's on the new engines ?

I just shut my truck off, after 10 days, mostly idleing @ 1200 rpm, winter front almost closed off, running at 200 deg F ( very cold out ) heater MUST be on recirculate, not fresh, to keep engine temp. up.

When I go to the arctic, I belly tarp, the engine & trans. maybe 50 wt trans oil in the hubs too...

If I owned the truck, I would use synthetic oils, soo expensive for a big company to change over.... $$$$$

I always changed oil & filters every 300 engine hours when I had my own dump trucks. (They were also Macks).

Complete grease job every 5 working days.

The company I work for now adheres to a similar schedule.

Oil & grease are cheaper than parts and much easier to install.