Cat C-7

davekc

Senior Moderator
Staff member
Fleet Owner
A 3126 and C-7 are basically the same thing. There are also a short and long block version. Very durable engine, or at least the ones we have had in the past have been. If the block isn't damaged, they can be sleeved if you are willing to give up a little displacement if rebuilding.
 

Deville

Not a Member
The C-7 in particular the early models, I think from 2002-2004 had alot of Huei pump issues which led to injector, head & turbo failures. CAT is n ot known for honoring warrenties on the c-7.

Granted I have heard more horror stories than positive ones. It always seems that way. CAT made alot of these engines. I'm sure there are more good ones than bad ones. For what it's worth I like my 3126. I'm at 523,000 i'm hopeing for 750,000
 

Tennesseahawk

Veteran Expediter
The C-7 in particular the early models, I think from 2002-2004 had alot of Huei pump issues which led to injector, head & turbo failures. CAT is n ot known for honoring warrenties on the c-7.

Granted I have heard more horror stories than positive ones. It always seems that way. CAT made alot of these engines. I'm sure there are more good ones than bad ones. For what it's worth I like my 3126. I'm at 523,000 i'm hopeing for 750,000

Funny... I'm at 523k on my 3126 as well. But since I got it at 503k, I'm not counting on 3/4 of a million on it. In fact, I cross my fingers everyday. LOL

So what's the deal with the c-7? Is it a wet sleeve or dry? What would a replacement cost?
 

davekc

Senior Moderator
Staff member
Fleet Owner
They are a dry sleeve but can be sleeved on a rebuild if the cylinder walls aren't trashed. About half the price of a full engine replacement.
 

Picklett

Seasoned Expediter
I don't know if this will help; but, here goes. We just had our C9 Cat rebuilt at 800,000 miles at the best Cat shop in Tennessee (IMHO) and the final bill was $20,157. I feel it was a bargain since the rebuilt warranty is better than the original. Hope this helps.
 

Deville

Not a Member
Funny... I'm at 523k on my 3126 as well. But since I got it at 503k, I'm not counting on 3/4 of a million on it. In fact, I cross my fingers everyday. LOL

So what's the deal with the c-7? Is it a wet sleeve or dry? What would a replacement cost?

I cross my fingers everyday too.
 

RETIDEPXE

Veteran Expediter
best Cat shop in Tennessee (IMHO)

Which Cat shop is it, if you care to share, and does the $20,000 include any extra $$'s for extended warranty? I'm thinking more towards slipping in a long or short block when the time comes (my C9 has 760,000 mi.s, burns 1 gall Rott T6 synth every 5,000 mi.s, but has done this now for forever).

I've also found some used like this 2005 C9 9DG motor; Used C9 Caterpillar Engine Used Cummins Diesel CAT Engine Motor's For Sale | used caterpillar enginesüsed cat engines | visonerv.com for $11,000, but no warranty (I don't depend on warranties anyway) and I'd want to check out the ecm history on the "low mileage" statement somehow. I did read that federal and/or CARB requires replacement with same year motor to stay emission's compliant so I'd need an '06 motor I think.
 

jt1980a

Active Expediter
They are a dry sleeve but can be sleeved on a rebuild if the cylinder walls aren't trashed. About half the price of a full engine replacement.

You will loose some displacement from sleeving this motor but it can be done. I would seriosly caution against this though unless the engine is in a lawn mower or a weed eater. The c7 is already underpowered and over rated as compared to its competitive counterparts.
 

rollincoal

Expert Expediter
Owner/Operator
I don't know if this will help; but, here goes. We just had our C9 Cat rebuilt at 800,000 miles at the best Cat shop in Tennessee (IMHO) and the final bill was $20,157. I feel it was a bargain since the rebuilt warranty is better than the original. Hope this helps.

That's the same price as a C15 in a class 8 truck. Doesn't help that almost 10% of that out the door price was sales tax, but still, CAT's aren't cheap. Just curious what CAT house you are talking about?
 

guido4475

Not a Member
When I had my FL-70 with a 3126 in it, I read the engine owners manual front to back.What scared me is the life expectancy of the engine in that manual.They had it in hours, and it basically translated to around 250,000 miles.I had Ohio Engine Power in Richfield do all of the work on it, and the min mechanic once told me to have the valves adjusted at 40,000 miles increments, and I won't have a problem.Do it with the engine completely cold, and make sure the mechanic knows to back the adjusting bolt off, then re-torque it.Some just put a torque wrench to it, and that's it.What happens its that the valves on a 3126 have a tendency to tighten up over time, slamming the valve in to the head, eventually snapping off the head of the valve into the engine.I must of listened to the right guy, because it is still going at last heard of mileage of 828,000 miles, no problems.Thank God the guy I sold it to listened to what I told him.But, I love a Cummins engine, so much cheaper to repair and rebuild as well as fuel mileage, in my opinion.
 

jelliott

Veteran Expediter
Motor Carrier Executive
US Army
I don't know if this will help; but, here goes. We just had our C9 Cat rebuilt at 800,000 miles at the best Cat shop in Tennessee (IMHO) and the final bill was $20,157. I feel it was a bargain since the rebuilt warranty is better than the original. Hope this helps.

WOW, a class 3 rebuild on an mbe4000 is like 15k, even our series 60's are only like 17k. That seems really high.
 

Picklett

Seasoned Expediter
The CAT shop is Stowers in Crossville, TN. Their main office is Knoxville, TN; but, we have never used them. We live near Nashville and Crossville is closer to us. Yes, I know there is a CAT shop in Nashville; but, there's no way we will EVER use them again. Screw me once--Shame on You, Screw me twice--Shame on me. Trust me, not gonna give them the chance!! I don't know if this charge is reasonable or not I just know that the work they do is excellent & if the price seems fair to me then I am the only one that matters. If this engine had a moving part then it was replaced & the 4 year warranty covers everything but seals & gaskets & CATFinancial financed the work. Could not be happier.
 

Deville

Not a Member
When I had my FL-70 with a 3126 in it, I read the engine owners manual front to back.What scared me is the life expectancy of the engine in that manual.They had it in hours, and it basically translated to around 250,000 miles.I had Ohio Engine Power in Richfield do all of the work on it, and the min mechanic once told me to have the valves adjusted at 40,000 miles increments, and I won't have a problem.Do it with the engine completely cold, and make sure the mechanic knows to back the adjusting bolt off, then re-torque it.Some just put a torque wrench to it, and that's it.What happens its that the valves on a 3126 have a tendency to tighten up over time, slamming the valve in to the head, eventually snapping off the head of the valve into the engine.I must of listened to the right guy, because it is still going at last heard of mileage of 828,000 miles, no problems.Thank God the guy I sold it to listened to what I told him.But, I love a Cummins engine, so much cheaper to repair and rebuild as well as fuel mileage, in my opinion.

I need to have this done on my truck it's been a while since it was done. I'm having a hard time finding a mechanic I can trust to do it the right way.
 

rollincoal

Expert Expediter
Owner/Operator
The CAT shop is Stowers in Crossville, TN. Their main office is Knoxville, TN; but, we have never used them. We live near Nashville and Crossville is closer to us. Yes, I know there is a CAT shop in Nashville; but, there's no way we will EVER use them again. Screw me once--Shame on You, Screw me twice--Shame on me. Trust me, not gonna give them the chance!! I don't know if this charge is reasonable or not I just know that the work they do is excellent & if the price seems fair to me then I am the only one that matters. If this engine had a moving part then it was replaced & the 4 year warranty covers everything but seals & gaskets & CATFinancial financed the work. Could not be happier.

Always good to hear on the better shops from guys who've actually used them. Nashville CAT would be Thompson which is actually in La Vergne, TN that's their corporate headquarters/big shop. Haven't ever dealt with them other than having my truck dyno'd there several years ago but their Manchester, TN location is hands down an A#1 shop been using these guys for several years and never felt boinked over. Great diagnostics and repair work. If you're ever down this way and need a CAT house these guys won't mess you over.
 

Doggie Daddy

Veteran Expediter
Always good to hear on the better shops from guys who've actually used them. Nashville CAT would be Thompson which is actually in La Vergne, TN that's their corporate headquarters/big shop. Haven't ever dealt with them other than having my truck dyno'd there several years ago but their Manchester, TN location is hands down an A#1 shop been using these guys for several years and never felt boinked over. Great diagnostics and repair work. If you're ever down this way and need a CAT house these guys won't mess you over.

I can say the same thing about Ohio Cat in Canton,OH, it's a small shop but the tech's really know their stuff.

Sent from my DROID BIONIC using EO Forums
 

dieselmech

Active Expediter
Ive had good and bad from all sorts of drivers running it. Like said before, its pretty much a 3126e with an updated fuel system and a few extras to comply with the wonderful EPA regs. You can "sleeve" it but its not recommended for more than a hole or two since its more to salvage if you drop a valve or score up the wall. When in the right application they seem to hold up pretty good, considering its running a full liter less than the cummins (which ive heard has plenty of bottom end problems). The guys running a maxed out rating should really be looking at a c9 sized engine, the high ratings on the small guys are there for initial cost to lower the prices of trucks not because its ideal to run that much HP.
 
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