Newbie Question (Searched forums thoroughly) Purchasing a Freightliner M2. Need help.

greasytshirt

Moderator
Staff member
Mechanic
Do you think those issues could be caused by a failed piston cooler or lean condition caused by a faulty fuel injector? Because of the heaviest gouging adjacent to the piston pin axis, would indicate an overheat condition. The piston expands the most around the largest mass, that around the piston pin and when the overheat causes expansion, this is what you see. I am not a fan of parent bore blocks because of the cost of repair, but there are mobile machinists that can cut the bore in frame just like they cut counter bores in Cummins blocks.
Every piston got hot. You can see where material is missing on each piston. It evaporated.
This engine may have had gasoline in it. No one would fess up. I don't think it had a fuel tank on it when it arrived at our shop. There was definitely something screwy going on, and no one was talking.

The head was also trashed. It looked like an oxy/acetylene torch was used to burn holes between the exhaust valves and valve seats. The harmonic balancer, HPOP, and flywheel survived, and that's about it.

This failure's magnitude is certainly an outlier, but the C7 (in my opinion) still has shortcomings that are inexcusable. The parent bore block being the worst part. The super hard, brittle piston rings break and shred the relatively soft block. The valves have an annoying tendency to have their heads snap off if there's any guide wear, if they aren't adjusted perfectly and on time, and leaking injector tips definitely raise piston crown temps to unsafe levels.

Luckily the aftermarket has a lot of these problems solved. There are US-based companies that offer pistons that are higher quality with rings that are more ductile and don't break, and they wear the bore much less, and valves are available that are better built and are much tougher. LA Sleeve makes a cylinder sleeve that is tough and hard. That matched with a nice ductile ring means many many miles of consistent performance and little wear. The expense to switch to these parts is still significant, and working on a C7 in the M2 chassis is an exercise in patience.
 
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greasytshirt

Moderator
Staff member
Mechanic
Oh man... Now you got me scared. I bought the truck. Paid $17,000.00 cash.

Feel like it was a mistake... But we shall see. Going 2,551 miles between now and next Sunday delivering Christmas Trees for Santa 'N Sons tree farm out of Junction City, OR.
All the advice I can offer you at the moment is to buy clean fuel,keep it clean, don't be afraid to change fuel filters on an abbreviated schedule, have the valves adjusted by someone who knows what they're doing, and have the fuel injectors evaluated. Replace any that are marginal.
 
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jjtdrv4u

Expert Expediter
wish you had bought a C9, they have better track record...also with Allison automatic, they are ironclad...thousands on the road, although Cat and Freightliner are awfully expensive to work with...like all the rest....no one is cheap....
 
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Jonathan

Seasoned Expediter
Owner/Operator
Unreal. Well I better have cash set aside then. I found an old Penske sticker in it... Could have began life as a Penske truck... fleet or rental? Guy I bought it from seemed a bit shady...

Well - Load 1 delivered. 1,300 miles in and truck is pretty freakin' sweet! More power in this old C7 than my 2015 Hino 268!

I stopped at ProFleet Lube in Lodi, CA and had the elite PM service with Cat filters done. They did discover that truck had wrong fuel filter on it. It has 2 stage fuel filter system. $281.50.

Averaging 7.1mpg with cruise set at 62mph and crossing the Siskiyous (mountain pass between Oregon and California.)

Anyway... writing on phone.... will type more later.
 
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greasytshirt

Moderator
Staff member
Mechanic
Unreal. Well I better have cash set aside then. I found an old Penske sticker in it... Could have began life as a Penske truck... fleet or rental? Guy I bought it from seemed a bit shady...

Well - Load 1 delivered. 1,300 miles in and truck is pretty freakin' sweet! More power in this old C7 than my 2015 Hino 268!

I stopped at ProFleet Lube in Lodi, CA and had the elite PM service with Cat filters done. They did discover that truck had wrong fuel filter on it. It has 2 stage fuel filter system. $281.50.

Averaging 7.1mpg with cruise set at 62mph and crossing the Siskiyous (mountain pass between Oregon and California.)

Anyway... writing on phone.... will type more later.
I'm glad you stopped and got that wrong fuel filter replaced. It's :censoredsign: like this, I tell ya.
 
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Jonathan

Seasoned Expediter
Owner/Operator
Progress Report:
  • So far I've had to change the oil and discovered the fuel filters were the wrong ones. ($281.50)
  • Then the Liftgate (Waltco tuckaway) quit while on a move. Tech discovered broken hose, low fluid, and seized hinge pin. Precision Liftgate from Milwaukie, Oregon came out and did a field repair ($301.30).
  • A fuel leak was discovered during a DOT inspection. Gilman's Big Rig Repair came out and did a field replacement on a Sunday. ($231.11)
  • The rear brakes were nearly metal to metal and beyond the pull point so I had those replaced ($453.00)
    • Total: $1,266.91
So, I have decided that the gentleman to whom the truck belonged prior to my ownership may not have taken the greatest care of it!

These are all very minor repairs and I am not worrying about it or regret my purchase decision, but I just thought I'd update everyone watching my journey of my first big truck purchase.

If you have a budget to purchase a vehicle, it is advisable to make your purchase at a price below your cash on hand instead of being drawn in to what you can "afford."
 
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Jonathan

Seasoned Expediter
Owner/Operator
Update:
---------------------------------------

Brought C7 Cat to Peterson Caterpillar here in Portland Oregon with misfire at all RPM's and gray smoke out of the exhaust and blow by.
  • Discovery: Cylinder 3 is not firing due to scored cylinder walls.
  • Recommendation: In frame rebuild.
  • Purchaesed mileage: 303,000.
  • Dead mileage: 310,000.
  • Purchase Cost: $17,000.00
---------------------------------------

Lesson: Haven't figured that one out yet. I know there is a few here.
 

tknight

Veteran Expediter
Is a c7 a parent born motor or replaceable sleeve 300k is a bit premature for that ! Unless really abused.
 

Jonathan

Seasoned Expediter
Owner/Operator
Yeah - I mean if I rebuild it then I can guarantee good mileage... if I buy a used then it's another gamble.
 

tknight

Veteran Expediter
Correct but guarantee good miles that's another issue if you reman it it'd be better Id think
There's a big difference throwing in parts and reman
 

Lawrence

Founder
Staff member
Oh man... Now you got me scared. I bought the truck. Paid $17,000.00 cash.

Feel like it was a mistake... But we shall see. Going 2,551 miles between now and next Sunday delivering Christmas Trees for Santa 'N Sons tree farm out of Junction City, OR.

Glad the forum community was able to shed some light on some of the risks involved. Please report back once you get rolling. Best of success in the meantime!
 
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