Pete 386 with the Paccar MX engine

Discussion in 'Peterbilt Forum' started by Flying Finn, Feb 22, 2011.

  1. Flying Finn

    Flying Finn Heavy Load Member

    Jun 22, 2010
    Ontario, Canada
    So I am curious about the Paccar MX engines out now. So far I have seen some reviews and they are all pretty good. Problem is, the reviews are mainly by Pete mechanics and reporters at Pete training facilities.

    The engines have been used in Europe for many years as the DAF engines, I think. They are supposed to get great fuel mileage and be quite reliable.

    Anyone have any firsthand experience with the engines in a truck doing day to day OTR work? They only go up to 475 horse and like 1650 pounds of torque. Seems a little weak not being able to go to higher HP ratings. The blocks are the compressed iron graphite (or something like that, having a brain fart on the exact type) so they tout much lower weight and much higher strength. My concern would be the blocks being fragile. Take most steels, if you make them harder and harder they become much more brittle.
  2. Nevs

    Nevs Light Load Member

    Dec 25, 2010
    flyover country (Iowa)
    I was in Rush Peterbilt in Denver about a month ago having a pinion seal replaced. There was a driver in there from Billings, Montana, he drove for a small company up there I won't name. Anyway, he was in there for the second time for the week with emmisions issues, lights flashing on the dash and derating the power. Something to do with the egr cooler leaking or something. Anyhow, they had to strip the whole side of the engine down to get to it and then they didn't have the parts to fix it. Driver had been there for over 24 hours and wasn't happy to say the least. He also mentioned the only place to buy filters to service it was from a Paccar dealer. I don't know if that's true or not, but he said they were spendy. They also had another one of their trucks in the shop that had blown up completely. A rod cap had come loose and destroyed everything. They were in the process of putting a new engine in that one. He wasn't impressed to say the least. He did say the power and economy were Ok, but not great, 6.0 pulling a reefer. I'm just repeating what he said, I have no experience myself, and don't want any!:biggrin_25525:
  3. hennpecked

    hennpecked Bobtail Member

    Feb 27, 2011
    fargo, nd
    I have been driving an MX engine now for 4 months now and have no complaints. It is in a 2011 386 rated at 455 HP. We are pulling a gross weight of 105,500 and it does rather well with mpg between 4.5 to 5 mpg depending on wind etc. I feel the mileage will get better when the weather warms up and truck gets more miles on it. So far I am pleased with the engine.
  4. madnow

    madnow Bobtail Member

    Mar 30, 2011
    Sulphur Springs TX
    We just purchased a 2012 pete 389 with the MX. Went 1000 miles check engine light came on. I am not saying dont buy one but I am suggesting an extended warrenty. We are changing from the cummin ISX. I will never buy another cummin product EVER. In our homework the MX is about the best working right now. Good luck.
  5. mrtvtruck

    mrtvtruck Bobtail Member

    Feb 10, 2010
    Nashville, TN
    We have a T660 with a 485 MX. Have some minor issues with DEF light flashing and check engine light. Loaded around 70k, it is getting about 6.5 mpg right out of the box. No major complaints as of now.
  6. Kenworthsalesman

    Kenworthsalesman Bobtail Member

    May 7, 2011
    Since the paccar mx came out I have sold 8 trucks with them in them 4 of them were 4 Kenworth t800 rated at 485 daycab s and 4 were Kenworth t660 s 485 72inch bunks other sales people have been selling them to they army in the shop very much
  7. milskired

    milskired Road Train Member

    Jul 20, 2007
    Plainfield, IL
    Met a guy last week in a pete dealer who had one that was a co truck. Had 64K miles on it and had been in the shop 5 times. His EGR was being replaced for the 2nd time and he had 7 recalls on the truck. He hated it.

    DAFMAN Bobtail Member

    Sep 16, 2011
    hi iam a workshop foreman with DAF in the UK
    We have been servicing, repairing and overhauling DAF MX engines since 2006. The spec engine you have is alot more reliable than the early 2006-2009 european MX.We have had camshafts, turbos, emmission/ adblue faults, compressors, oil modules, oil consumption, cam followers and oil pressure faults regularly
    Latest spec engine is 100% better
  9. wire

    wire Bobtail Member

    Mar 21, 2010
    Mb. Canada
    Hey Flying Finn.
    I drive a new (2012) 386 with the MX rated at 455hp. My previous truck was a very sharp 379 with a 600hp Cat C15.
    It is still early days (3 months) but so far the MX is performing ok with no problems. The fuel mileage is averaging around 6.5 -7.0mpg compared to my old Cat powered Pete which averaged 5.3 - 5.5mpg so even taking into consideration the cost of the DEF we are saving around $1200 - $1500 a month.
    I realise that much of this improvement is due to the actual shape of the 386 compared to the 379 but i am sure that the engine is a large part of it.
    On a not so positive note, the pulling power of the MX is way down compared to the C15. Also the compression brake is not nearly so effective probably due to the smaller displacement.
  10. sr_smyth

    sr_smyth Bobtail Member

    May 30, 2011
    Terrace BC
    Have personally sold 12 MX powered units, 8 in vocational 367's and 4 in 388 highway hauler. Been very well recieved and so far (touch wood) very reliable. Yes, there has been a few recalls but most of those have been for software updates to prevent problems rather than fixing actual problems. I've been very impressed so far, much more so than the ISX powered units.
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