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Thread: Mack E7 question

  1. #31
    Senior Member Paystar's Avatar
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    Wow, this brings back memories. I was always a Mack man (still think the old mechanical motors rule)...but had a 2000 CH tractor with an E7 460 with some of these problems. Mine idled OK but it had that mystery "turn on/off real quick while driving" problem, that would leave the electrical malfunction light on. It also had a powerband like a light switch. One hill it would barely pull itself over, the next you would literally think the clutch was slipping because the rpms would suddenly shoot up, then look out, start grabbing gears. The dealer never could find the problem, they even changed all the pins in the ecm wire harness connectors. I recently saw it and spoke to the new owner and he said it is still doing it but said it pulls real strong now.

    Did I mention it was also one of the lucky ones that came from the factory with all the cooling galleries full of casting sand. Five air compressors and five dryers later they finally got it all cleaned out. Then it dropped a valve while parked idling at 125,000 km. Then the starter wiring caught fire while running with the pto on. Then the camshaft went at 300,000 km. Along with an air conditioning system that would freeze solid (was an update on that) and a recall on the engine oil pump that was too low on pressure. That's why I bought a Cat powered International.
    I still like Macks though and I hear good things about the new MP engines. Just wish I could still get a new R model with an E6 350

  2. #32
    Senior Member LowBoy's Avatar
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    A few years ago I was an employee for a short time for a big petroleum transportation company, and drove a CH Mack. It had a 400 and when it ran, it ran just good enough so I wasn't mad all the time. It also developed that electrical gremlin one time where I was going along and it'd literally shut off. One day it happened 12 times in an hour, I was loaded with 8500 gallons of gasoline going up the NY Thruway from Albany to Saratoga to a station. I had to keep starting it back up going 65 mph to get to the station to unload. Something about electrical problems...and GAS...I'm not sure what it is, but it was making me a little nervous.
    I called the so-called "mechanic" for the outfit, and for the first time in his life admitted he didn't know what it was, so bring it to Mack. It ended up being the wiring harness that plugs into the firewall that feeds ecm and a few other things. 4 feet of wire and labor was over $600.00.
    Shortly after that I remedied the entire problem by purchasing a '97 Peterbilt and became an owner-op again even though I said I'd never do it again. Electrical problems ended, but a whole new series of problems developed at that point...like all truck owners can relate to.
    "I can break an ANVIL..."

  3. #33
    Founder Steve Frazier's Avatar
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    I used to drive for a local food chain a number of years ago. One of our outside vendors always ran Macks, they had the R model when I started, but updated to the CH when they came out. I can't tell you how many times one of their trucks would be sitting behind the store dead in the water, it would crank but never fire off. I made quite a bit of overtime due to their trucks blocking the dock.

    This problem was so common it tarnished Mack's reputation as being a bulletproof truck. I had driven a DM600 for 2 years in heavy construction and had only seen one minor repair in that time from a 50 cent hose clamp blowing off the pressurized air line to the intercooler. I was really impressed with the beating that truck took and kept coming back for more. The problems that plagued the early CH series would make me think twice about buying one of them after having such good experience with the DM model.

  4. #34
    Senior Member LowBoy's Avatar
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    I have to agree on the earlier Macks being close to bulletproof. I did my time in a few (B-61, B-81, DM 800, DM 600, R-Models,) but never really aquired a "love" affair with them. I was always partial to a normal Cummins, Cat, Detroit powerplant with Roadrangers or two stick combos.
    I am surrounded by them (Macks) currently. Today I was in about an '85 R-Model waterwagon doing dust control for an hour. That was about all I need of it now for another month or better, and as long as nobody I know saw me in it, I'm cool.
    "I can break an ANVIL..."

  5. #35
    Senior Member Iron Horse's Avatar
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    I do'nt know how the Big Chiefs at Mack can sleep at night . With a proven and documented history of these trucks shutting down at speed it's only a matter of time until someone gets killed . The litagation will be severe and ongoing once a precident is set . And even if it was'nt the cause of the accident , what truck driver would'nt say "it just shut down and i could'nt control it " and if the shut downs do'nt get logged in the computor how would anyone dispute it . I'd be starring at the ceiling at night waiting for the call....

  6. #36
    Senior Member DigDug's Avatar
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    I have a old CH model with elec. 350. It has some electrical problems also . My top bank of fuses and relays in the glove box lost power , sounds like a easy fix , guess again . I ran a wire from the lower bank of fuses to power up the upper row , works sweet . My truck also shuts off for a split second , I always contributed it to needing new fuel filters but sounds like its common on other trucks and its electrical. I still love her , she's never left me walkin.
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    Last edited by DigDug; 08-21-2008 at 07:46 PM. Reason: I cant spell for sht

  7. #37
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    Any of you guys running the E7, check your exhaust manifold. Specifically around the turbo flange. Mine was broken all the way around and leaking hot exhaust onto a plastic diesel return line. Luckily, I recently purchased a spare engine for this truck (just in case) so I had a spare manifold. But guess what, the manifold on the spare engine is cracked as well. I'll be melting some nickel rod in that one later on this morning. I spent all night grinding the injury out. I just need it to hold until the new one comes in. But that manifold is on national back order and there are none to be found anywhere. I wonder why?

  8. #38
    Senior Member Pecord Exc's Avatar
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    This post makes me glad that our RD688 is as old as she is a 97, mechanical motor! knock on wood she has treated us well, just over 250k miles. It was a lumber truck that we had T&T Body king up in Latham build for us! Ill get some pics soon!

  9. #39
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    Quote Originally Posted by King of Obsolete View Post
    buddy barry has the blue mack which is a E7and the thing is acting up. driving it at highway speed, all it does is act as if sme one is turning the key on and off. the electronic malfuction light comes on and goes off. we have to drive the truck 1200 kms to the nearest mack dealer which treats us pretty good. they can't guess what the problem is on the truck over the phone.

    thansk
    KoO
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    My 2001 Vision 427 use to do that, 1st owner did not properly remove the qualcom programs from the ecu local mack dealer fixed it in a sec. hasn't acted up in over a year

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