Circa 2002-2004 Cat C7 Heui Issues

the c7 that you need to avoid is the 2007 emission engine. this has a common rail fuel system the engine serial number will start with c7s cat could not make this system work reliably and they dropped out of the truck engine market when the 2010 emissions were required

I also agree with Brett & Scott. I'm a retired trucker and Catapillar came out to our shop and told or mechanics to add 1 gallon of motor oil above full to all C-7 CAT engines to protect bearings inside the engine. The CAT people also said overfilling the crankcase will not hurt the engine. All of our C-7's were in delivery trucks. I prefer Cat motors over all others having driving them for 44-1/4 years OTR. The last CAT engine that I drove had inframe overhauls at 750,000 miles and 1,200,000 miles, and 1,300,000 miles after the 3rd inframe my boss sold the truck to a local ship hauler and that truck is still going up and down I-5 to this day and that speaks for itself.

As usual, Brett is right on. But basically, just about any Freightliner chassis coach built prior to around mid to late '03, is touting the 3126 version CAT. After around Sept or so of '03, the C-7 was introduced. There are three, over the road versions of the C-7. A 300HP, a 330HP and, a 350HP. All of them put out 860 ft. lbs. of torque.

The C-7 was not only used in motor home chassis's. That engine is in zillions of over the road trucks, delivery trucks, tractor-trailers, FIRE TRUCKS(many), cement trucks and more. No one on here (this site) knows the ratio of just how many C-7s have had HEUI issues, vs the total amount of C-7s produced and, are still putting thousands and thousands of trouble free miles on our roads.

As Brett stated, we only read on here about the infamous HEUI problems. And, how many is that, actually??? And, don't forget, Cummins has had its share of reliability issues too, on some of its series engines. Wrist pins, continuous blown head gaskets, and a few others come to mind on some of them. But, again, who knows just how many of the Cummins engines had those series problems?

So, pic your poison. Our coach, an '04 Itasca Horizon 36GD with the C-7 330HP CAT, has 63K on the clock and, is running down the road strong and healthy. We tow around 6500 lbs. worth of 2011 GMC Sierra Extended Cab 4x4 with a Rampage lift and, an '08 Honda GL 1800 Goldwing in the back of it. And that engine does great.

Keep the radiator and CAC fins clean, change your oil on time and regularly, and change your ONLY or, dual fuel filters and, that CAT will serve you well.
Scott

#1. The number of HEUI failures is not that high-- but those who have had it fail are the only ones who bring up the subject.

#2. To determine exactly what system a Caterpillar engine has one it (depends on ENGINE build date), call the Caterpillar RV Hotline with the Caterpillar engine serial number: 877 777-3126.

FYI, I would rather have a C7 over a Cummins B and would rather have the Cummins C or L over the C7. Size matters, particularly when it comes to torque.