Cat C7

My only experience with cat C7 is school bus applications. They work well until they don't..
Usual failure point is broken piston rings that score the cylinders. These are parent bore engines so they need machine work to repair.
Found them loud, and yellow paint on anything is expensive..

 

There is no perfect engine, especially at those miles and hours. It's all about the maintenance and driver. At that mileage and hours you best be planning on repairs...
I've often wondered why the little kittys broke piston rings in school buses. Most I've talked to have blamed the bus duty cycle. Start cold, run like hell for 2 hours. Cool down, and do it again in the afternoon.

 

I used to see broken rings in the 3116's also. They were not school buses. Personally thank the C series is the better of the two engines.

 

I liked the ISC I used to run. Was turned up to 350hp 1200tq. Until it dropped a valve at 700 000km.

 

I’ve got a ‘99 FL60 that I put about a million and 60 something thousand on. The 3126B 250 hp was replaced twice in that time. Original one went around 471,000 and started using a gallon of oil a week. Still ran and pulled ok but wore out. Was normally running 1,300 miles a week.
Second one went almost 500,000 when out of nowhere it dropped a valve and destroyed a cylinder, piston, and turbo.

When I was running it this truck was fired up at 5:30 am and was not shut down till 7 pm 4 days a week or 10 pm one day a week. Hauled 33,000 gross pushing lots of wind running 2400 rpm on highway.

3126/C7 engines blocks are dry sleeves and have to be replaced with new replacement blocks. Crate engines from Cat that were new blocks and remaned everything else were around $24,000 each time.

It’s sister truck is a ‘03 and has a 3126E and is still chugging along for the new owner with around 540,000 on original engine. It never worked as hard as the ‘99 tho.

Fuel injection pumps and injectors were always the weak parts everything else did great for us.