is the paccar MX13 that bad?

Discussion in 'Questions From New Drivers' started by ad356, Apr 23, 2019.

  1. ad356

    ad356 Road Train Member

    1,607
    1,584
    Mar 13, 2017
    0
    one of our own trucks, truck 79 spun a rod bearing at 330K miles. the guy in the shop said the block is also toast and the entire engine has to be replaced. its a 2015 T680 day cab. i heard from another one of our drivers that yet another milk hauler is experiencing a similar failure with one of their paccar engines and at similar mileage.

    are these engines a bad engine or are they just not well suited for heavy loads like hauling milk. it seems like allot of the milk haulers are buying them, personally i dont know why are they arent opting for the cummings ISX15, but i hear the newer ISX15's have their own failure issues.
     
  2. Intothesunset

    Intothesunset Road Train Member

    1,674
    3,148
    Apr 15, 2019
    truck
    0
    How often was the oil changed? 20K interval?
    Was the overhead ran yearly?
    Any of these new engines will last longer if you do not fallow the manufacturer guidelines.
    If you go 50K on oil they will loose rod bearings, or spin main bearings.
     
    Bean Jr. and magoo68 Thank this.
  3. Snow Monster

    Snow Monster Light Load Member

    206
    464
    Feb 9, 2019
    0
    Details are sparse, but one thing to consider is the way the trucks are driven, or programmed.
    If you're pulling heavy loads and running the engines at 1100 or 1200 rpm and it's working fairly hard, the cylinder pressures are a lot higher than at a higher rpm and create more heat and put heavy strain on the components causing premature wear and/or damage to the engine. (head, rods, crank, etc)
    Running at 1200 rpm is okay for half a load, but you put some weight on or buck a nasty wind, you're better off to drop a gear and run at 1500 or 1600.
    If you read the literature for the engine there's likely a reference to increasing engine speed when pulling loads over 80,000 lbs.
    I know I've read that in Cat literature, but the physics in every brand of engine are the same and should apply universally.
    (suck, squeeze, bang, blow)
     
    Bean Jr., stwik and Intothesunset Thank this.
  4. Intothesunset

    Intothesunset Road Train Member

    1,674
    3,148
    Apr 15, 2019
    truck
    0
    But lugging my engine gives me very good fuel mileage.
    Aren't new engine literature telling owners to run on torque when loaded??
     
    bottomdumpin and Bean Jr. Thank this.
  5. Snow Monster

    Snow Monster Light Load Member

    206
    464
    Feb 9, 2019
    0
    Yes they are, but they're talking about the 70% of the trucks that run half loaded all the time, or under 80,000 lbs.
    Torque has nothing to do with getting you down the road, it's the horsepower that's measured.
    It takes X amount of horsepower to maintain a given speed, so if you're engine is capable of making 500 hp at 1200 rpm and it only takes 200 hp to keep you rolling at desired speed, torque doesn't really matter, only that you're operating in the engines power band, which hp and torque curves will show you.
    Just because the engine is spinning faster doesn't mean it's using more fuel, because if you drop a gear to maintain a given speed. it's not working as hard and your gauges should show it.

    I looked but couldn't find anything for Paccar, but I found the Cat literature, should say nearly the same thing.

    http://www.performancediesels.co.nz/vdb/document/6

    80,000 lb GCW or less

    Less than 1750 lb-ft: 1400 rpm @ 65 mph (105 km/h)

    1750 lb-ft and above: 1325 rpm @ 65 mph (105 km/h)

    90,000 lb GCW or more

    1500-1650 rpm @ cruise speed

    Multi-torque: 80,000 lb GCW or less

    435-hp, 1550/1750 lb-ft: 1325 rpm @ 65 mph (105 km/h)

    475-hp, 1650/1850 lb-ft: 1325 rpm @ 65 mph (105 km/h)
     
    Bean Jr. and Intothesunset Thank this.
  6. Snow Monster

    Snow Monster Light Load Member

    206
    464
    Feb 9, 2019
    0
    Here's a video that explains rpm and torque pretty well.
     
    NightHawk365 and Intothesunset Thank this.
  7. GreenPete359

    GreenPete359 Road Train Member

    1,406
    2,112
    Oct 21, 2017
    Driving my recliner
    0
     
    booley Thanks this.
  8. Intothesunset

    Intothesunset Road Train Member

    1,674
    3,148
    Apr 15, 2019
    truck
    0
    I do not see a truck engine lasting long if landed near 80k bucking wind, and going uphill if your keeping rpm under 1400 rpm.
    But that's just me.

    I sure do respect Rawze, but I can not respect that Cummins ISX.
     
    Bean Jr. Thanks this.
  9. Cat sdp

    Cat sdp . .

    9,404
    16,533
    Apr 8, 2012
    Orion's Belt
    0
    Last edited: Apr 24, 2019
    AModelCat Thanks this.
  10. daf105paccar

    daf105paccar Road Train Member

    4,897
    4,262
    Apr 15, 2012
    0
    I'm biast.
    I've earned a lot off money with my MX.

    @Cat sdp
    Allready read this thread.

    Ps caesar cannot see you mentioned him.
    Should have put a space between the . and the @
     
    Cat sdp Thanks this.
  • Draft saved Draft deleted