I despise the CAT C7.

[greasytshirt]

A buddy of mine has an '04 Freightliner M2 with a CAT C7. Approx 350k miles.

He was finished for the day and was cruising home unloaded when poof, it's blowing light colored smoke and it's down on power and misfiring. He limped it back home.

We started dicking around with injectors. Replaced injector on #6 cyl. Fired up engine, exhaust manifold stayed cool to the touch. Oh no.

We removed the head earlier this afternoon. One third of #6 piston crown has evaporated. It literally changed from a solid to a gas and exited the engine out of the tailpipe. Unfortunately, it also scuffed the cylinder walls on #s 4, 5, and 6.

So, where's a good place to buy a reman CAT C7? We're looking for a longblock that comes with injectors and a turbo. Some sort of warranty would be nice, too.

 

[Dynamite 1]

Other than cat you probably have to look online. What about replacing it with a C9 instead ? They did put them in 106's and are a more dependable engine !!!

 

[usafk9]

dieselenginetrader.com

 

[LDB]

Good luck to your friend. Cat engines are garbage and the company is worse than garbage.

 

[guido4475]

I have a freind that has a sterling in texas right now with a bad trans but a good 3126 in it that was rebuilt by cat a couple of years ago. You can most likely get the whole truck real cheap. And this is a NICE truck. Spotless box. Polished alum wheels. 96 inch sleeper. Mint interior. Theres just something about the trans in those trucks as to why he won't fix it. So it sits. Too bad as I would consider it if it wasn't for the trans issue. Its an early autoshift I think.

 

[highway star]

Too bad as I would consider it if it wasn't for the trans issue. Its an early autoshift I think.

Do you know what the issue is? Just curious... My Mercedes 6 speed auto shift has given me fits this year.

 

[Daffyduck528]

Good luck to your friend. Cat engines are garbage and the company is worse than garbage.

But they do make a good looking engine. That CAT yellow when clean really pops good at a truck show.



Disclaimer: I own a c13. It will be the last CAT I own.

 

[guido4475]

Do you know what the issue is? Just curious... My Mercedes 6 speed auto shift has given me fits this year.

I do not recall exactly what it was doing to make it in-operable, but I do remember the dealer telling him that that particular model trans was a test trans of some sort and didn't find it's way into too many trucks because of the issues it had during the testing phase.They said it is virtually impossible to replace it, supposedly. I still think there can be a way to put something different in it. It's a 3126 engine, the trans possibilities can be endless. It is way too nice of a truck to let go to the scrap yard, in my opinion. Yes, the 3126 is not Cat's most best engine, that's for sure, but with a CORRECT overhead ran at every 40,000 miles, it should run forever. My old FL-70 is still on the road with over 900,000 on it....never rebuilt yet...The owner is doing things exactly how I did them, and I did them exactly how Ohio engine power told me to do it if I wanted it to last.

 

[jamom123]

I do not recall exactly what it was doing to make it in-operable, but I do remember the dealer telling him that that particular model trans was a test trans of some sort and didn't find it's way into too many trucks because of the issues it had during the testing phase.They said it is virtually impossible to replace it, supposedly. I still think there can be a way to put something different in it. It's a 3126 engine, the trans possibilities can be endless. It is way too nice of a truck to let go to the scrap yard, in my opinion. Yes, the 3126 is not Cat's most best engine, that's for sure, but with a CORRECT overhead ran at every 40,000 miles, it should run forever. My old FL-70 is still on the road with over 900,000 on it....never rebuilt yet...The owner is doing things exactly how I did them, and I did them exactly how Ohio engine power told me to do it if I wanted it to last.

This may be a dumb question but what exactly is an overhead, how much is the cost, and why every 40, 000 miles?

 

[Deville]

This may be a dumb question but what exactly is an overhead, how much is the cost, and why every 40, 000 miles?

Valve adjustment. 40,000 miles seems a little overkill. They are normally done every 100,000 miles.

A valve adjustment, and a rigid oil change schedule is critical in keeping the 3126 running smoothly.

I'll change the oil on my kitty every 4 months or 8,000 miles whatever comes first. I'm having a secondary oil filter system put on as well next PM. It runs well, A/C works, tires and brakes in excellent condition, new shocks and airbags put in 6 months ago and still looks good so it's worth maintaining and holding on to. Plus, I have so many new parts in it mostly minor parts that it's good to go for a while.

 

[guido4475]

Valve adjustment. 40,000 miles seems a little overkill. They are normally done every 100,000 miles.

A valve adjustment, and a rigid oil change schedule is critical in keeping the 3126 running smoothly.

I'll change the oil on my kitty every 4 months or 8,000 miles whatever comes first. I'm having a secondary oil filter system put on as well next PM. It runs well, A/C works, tires and brakes in excellent condition, new shocks and airbags put in 6 months ago and still looks good so it's worth maintaining and holding on to. Plus, I have so many new parts in it mostly minor parts that it's good to go for a while.

You're first paragraph in you're reply is why so many have had major issues with this engine continuously dropping valves to begin with.

The reason for the 40,000 mile overkill of having the valves adjusted are like this...

For some unknown reason, the valves on a cat 3126 would, over time, begin to tighten themselves up as time went on. And when it would start doing this, the head of the valve would just slam that much harder onto the valve seat on the head, eventually snapping the head of the valve off and ...well, ka-boom.....new engine time....

So by having the valves adjusted every 40,000, what is happening, and this is only if the guy who is adjusting the valves is doing it right, and by that I mean with a cold engine, and backing off the adjusting nut completely and than re-torquing it. So many mechanics just take a torque wrench to the adjusting nut and think it is fine, when in all actuality, it is still over-tight, generated by the valves doing that self-tightening thing that cat could never figure out, which blew my mind....

Pay a little now, or pay a lot later, is what Cat back home told me. I trusted them, and I had one very dependable, smooth running, long lasting Cat back in the day.

 

[greasytshirt]

I have a freind that has a sterling in texas right now with a bad trans but a good 3126 in it that was rebuilt by cat a couple of years ago. You can most likely get the whole truck real cheap. And this is a NICE truck. Spotless box. Polished alum wheels. 96 inch sleeper. Mint interior. Theres just something about the trans in those trucks as to why he won't fix it. So it sits. Too bad as I would consider it if it wasn't for the trans issue. Its an early autoshift I think.

I'm not sure he'll want to drive halfway across the country for it, but I'll run it by him. Thank you.

We're going to be doing this in his backyard, so I want the engine to be plug-n-play. Getting the transmission out with a transmission jack on a piece of plywood is gonna be fun. I guess we're gonna need to rent a forklift too.

This plan is flawless.

 

[LDB]

How much does it cost every 40k miles?

 

[greasytshirt]

How much does it cost every 40k miles?

A valve adjustment? I can't see that taking more than about an hour.

 

[guido4475]

How much does it cost every 40k miles?

It was around 150 bucks back than.

 

[guido4475]

A valve adjustment? I can't see that taking more than about an hour.

That's about right. The thing was to make sure the engine was completely cold before doing it. I'd get there the night before and sleep there and they'd actually push the truck in the bay in the morning to do the job.

 

[fatboy1]

Midwest diesel service has lots of new cat surplus engines check them out.

 

[Deville]

You're first paragraph in you're reply is why so many have had major issues with this engine continuously dropping valves to begin with.

The reason for the 40,000 mile overkill of having the valves adjusted are like this...

For some unknown reason, the valves on a cat 3126 would, over time, begin to tighten themselves up as time went on. And when it would start doing this, the head of the valve would just slam that much harder onto the valve seat on the head, eventually snapping the head of the valve off and ...well, ka-boom.....new engine time....

So by having the valves adjusted every 40,000, what is happening, and this is only if the guy who is adjusting the valves is doing it right, and by that I mean with a cold engine, and backing off the adjusting nut completely and than re-torquing it. So many mechanics just take a torque wrench to the adjusting nut and think it is fine, when in all actuality, it is still over-tight, generated by the valves doing that self-tightening thing that cat could never figure out, which blew my mind....

Pay a little now, or pay a lot later, is what Cat back home told me. I trusted them, and I had one very dependable, smooth running, long lasting Cat back in the day.

Sadly, I dropped a valve about 10 years ago on this truck. I had not known about the valve adjustment. Not only did I drop a valve but I drove almost 200 miles like that before I couldn't go any more. The mechanics at Branford Freightliner were amazed. The guy who worked on the truck was shocked that it ran at all, and when it was cold it ran fine. The screen caught all the particles that feel into the sump. He told me if the motor didn't blow up after this then it never will.

I have followed the valve adjustment guidelines as part of my PM routine. So far so good.

I would also like to add that one of the most over looked maintence parts on these trucks is an air filter. I replace my air filter twice a year. These engines need a lot of fresh air and a blocked up filter will kill power and fuel economy. I still avg 10 MPG on my truck.

How much does it cost every 40k miles?

$250, with a new valve cover gasket.

 

[guido4475]

Sadly, I dropped a valve about 10 years ago on this truck. I had not known about the valve adjustment. Not only did I drop a valve but I drove almost 200 miles like that before I couldn't go any more. The mechanics at Branford Freightliner were amazed. The guy who worked on the truck was shocked that it ran at all, and when it was cold it ran fine. The screen caught all the particles that feel into the sump. He told me if the motor didn't blow up after this then it never will.

I have followed the valve adjustment guidelines as part of my PM routine. So far so good.

I would also like to add that one of the most over looked maintence parts on these trucks is an air filter. I replace my air filter twice a year. These engines need a lot of fresh air and a blocked up filter will kill power and fuel economy. I still avg 10 MPG on my truck.



$250, with a new valve cover gasket.

The overhead went up after awhile it sounds like. You ever look at the engine manual for a 3126? A lot of things are rated in hours, instead of miles, like maintenance and life expectancy of the engine....at the time mine translated to around 250,000 miles for the life expectancy of this engine. I was not overjoyed when I read that...My next FL-70 got ordered with a Cummins in it....How I loved that engine.....

 

[Deville]

The overhead went up after awhile it sounds like. You ever look at the engine manual for a 3126? A lot of things are rated in hours, instead of miles, like maintenance and life expectancy of the engine....at the time mine translated to around 250,000 miles for the life expectancy of this engine. I was not overjoyed when I read that...My next FL-70 got ordered with a Cummins in it....How I loved that engine.....

I saw that as well. I was horrified when I saw the amount of hours my truck had on it. Nothing you can do but maintain it as best you can.

I don't abuse my truck at all. I drive it nice and easy and take good care of it.