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CAT Lover · 06-12-2021, 08:00 PM

I joined this forum years ago to find out more info about CAT 3126 motors. I learned a lot and dispensed quite a bit of advice. My 3126 went in service in 1999 in a single axle tractor with a 64-inch bunk sleeper. with the Eaton-Fuller 6 speed tranny. When I took it in 2004 it had 365,000 miles on it. The frame was extended to accommodate a 24 foot-box with barn doors. I owned the truck from December 2004 until March 2021. I put 290,000 miles on it. I had 4 major mechanical issues.

1. I dropped a valve going to Rhode Island. Branford Freightliner repaired that.
2.Clutch job at 388,000 miles
3. Oil cooler repair. That was fairly easy it was all gaskets.
4. Replaced 1 injector, and all the injector cups and gaskets

That truck had a 32-quart sump. I was able to go 15,000 miles in between oil changes. I quickly learned that the CAT liked fresh oil. I eventually had it down to 6000 miles or 4 months. I used Howes diesel treatment on a regular basis, adjusted the valves every 100,000 miles, and changed the antifreeze every summer regardless of mileage. By some luck, I managed to avoid any issues with the HEUI pump and wiring harness, although it always threw a code for the HEUI pump no one could ever figure out why. My biggest issue was the cold starting. It was a PIA and we traced that back to a bad fuel regulator on the block of the motor. Once that was taken care of it started up on the first try 90% of the time.

I made a ton of money with that truck, the AC worked, everything worked. I had to sell it because my insurance company informed me last June that they would no longer insure it past June 2021 because of its age. it is a 2000 they don't insure trucks over 20 years old, but due to COVID and my long relationship with them they would give me another year. I attempted to insure it elsewhere but, it was too much money for a single truck.

For months I put off looking for another truck, finally, in March I had an opportunity come along that forced my hand and made me buy a truck with a refrigerated box. The old CAT has been sitting in there seldom used. I was the only one that drove her. I am the only one that knew how to make her purr. I never took her over 1900 RPMs unless I was in 6th gear on the highway or starting out heavy. She loved pulling heavy weight. I could load her up with 17,000 pounds and she would hum down the highway.

I took her out a bunch the last 2 weeks and used it like I normally did. I was sad to realize that she felt old. Maybe I am spoiled by the new truck, maybe time caught up to her the past 3 months, but she felt old. The body, the noise. The flex pipe had developed a hole so it was a little loud. Never the less I missed driving her and rowing gears. She still ran great.

I sold her to a mechanic that I know. I drove it in and said my goodbye. He pulled the motor, cleaned it up, and put it in another truck. I am happy her soul will live on even though her body is gone.

I bought a 2018 Freightliner with the Cummins B6 and the Eaton Procession 7 speed tranny. It's a much different truck. One thing I can't get used to is having the radio mounted on the dash. I liked it overhead on the driverside. Even when I drive my International I reach for the overhead console.

I wanted to thank everyone that I have chatted with over the years. You are a passionate bunch. The best advice I can give anyone is that the 3126 and C7's are great engines. They need to be used on a regular basis, and PMed on a regular basis. I am living proof that these engines will go hundreds and hundreds and hundreds of thousands of miles without needing to be rebuilt if used and properly maintained.

I'll be around.
TA

R.Wold · 06-13-2021, 05:09 AM

Nice write-up on your experiences. I operated several fire engines in the early 80’s built on cab-over fords powered by the cat 3208. They weren’t fast, and they had that distinct cat smell when idling (before exhaust collection systems in the apparatus bays) but they were dependable. They were never in the shop for engine issues. Just regular maintenance.

Dunrollin · 06-13-2021, 06:25 PM

Great write up, may your new truck do as well for you.

ftodaro · 06-15-2021, 08:17 PM

Great story. I bet the biggest mistake us RV owners make is the infrequent use. I will work on that

bowhunter72 · 06-22-2021, 10:31 PM

I'm surprised you got hy with replacing only 1 injector.

CAT Lover · 06-23-2021, 10:36 PM

Quote:

Originally Posted by bowhunter72

I'm surprised you got hy with replacing only 1 injector.

I was talking to the mechanic who I sold it too. He was telling me the little miss I had at idle was an injector too. I guess I should have done 2. Either way, it was a great truck and the motor lives on in a dump truck FL70 that's used as a snowplow and salt spreader.

Smitty77 · 06-30-2021, 03:41 PM

I always respect a person who respects and takes care of his equipment. Salute, and thanks for sharing.
Smitty

red knight · 07-18-2021, 11:08 PM

Just finished great trip. I believe close to 10 mpg. Only thing on a steep downgrade with exhaust brake the revs will get pretty high when trans drops to second. I apply brakes to bring down revs but still seems a little messy. Any thoughts. God is good.

CountryB · 07-19-2021, 05:25 AM

Quote:

Originally Posted by red knight

Just finished great trip. I believe close to 10 mpg. Only thing on a steep downgrade with exhaust brake the revs will get pretty high when trans drops to second. I apply brakes to bring down revs but still seems a little messy. Any thoughts. God is good.

The E/TCM will not allow the engine to over-rev while on the engine brake. If rpms get too high the transmission will upshift. So I would not worry about it. If the hill your coming down is too steep you may need to hit the breaks from time to time (and start down hill at a lower speed), but the engine wont be damaged.