Cat3126 or DT466

jwb

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I am considering the purchase of a MDT. I like the looks of the International, we even have several at my place of employment. The question is; which is the most reliable engine, the Cat 3126 or the DT466? I would prefer an engine in the 250 to 350 H.P. range with corrisponding torque. I will be towing a 34 foot 5th wheel. Any other suggestions would be greatly appreciated. Thanks....
 

nevrenufhp

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The 3126/ C7 has had many issues with dropping valves, broken internals, injection issues, and other little things like breaking connecting rods. You would be 10 times safer running a DT466, DT530 or DT570. Not too hard to find one in 250+ hp.
 

PackRat

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We have 2 rollbacks with DT's. I'd take one over a 3126, in a hot minute. Not sure about the C7. The only one I've played with was one that shelled the fan shaft bearings. It seemed pretty gutless, with an automatic, and 16' van box.

Another option is the C4500/5500 with a 330hp D-max. One of our customers has one, pulling 38' enclosed car hauler. He loves it.
 

Diesel_brad

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The 3126/ C7 has had many issues with dropping valves, broken internals, injection issues, and other little things like breaking connecting rods. You would be 10 times safer running a DT466, DT530 or DT570. Not too hard to find one in 250+ hp.

WHS;Sweet
 

bab029

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I've driven a DT466 equipped box truck and loved it. Plenty of power. I also drove an f650 with a 24V cummins that I really liked, but my favorite was a C6500 with the Dmax. A/C plus an air ride seat made for a bad-ass ride. The only issue with that truck was a coolant leak that nobody could diagnose, and when the reservoir got low, the engine shut off. It didn't matter if you were idling or going 75 with a full load (That's when it always happened to me). I guess the international 4600 really was my favorite.
 

towcat

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imho both motors are gutless. the IH has fewer problems and doesn't cost as much to fix in comparison to the CAT. i was recently spoiled badly with a buddy's 725hp CAT that ran like someone set the CAT on fire and this was with a 70ton rotator that was firmly bolted to it.
the 3126/C7 should be shot and put out of it's misery. Only bad thing I have to say about the DT466E is in IH 4700 towtrucks, I have yet to see one last beyond 150k/mi before needing a major inframe. for a big diesel, that's pathetic but it might be due to drivers not knowing how to drive it too.
 

strokermax

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i didnt think u needed that big of a truck for 34ft 5th wheel. my uncle tows a 40ft race trailer gooseneck with a 02 350. now of course he also has a 90s ford 6000 or something with a 8.3 cummins in it with that crappy alli behind it. ive heard nothing but bad about smaller CATs and newer 1s. The big CAT that could have 625hp factory is a animal from what i hear. if it was me id go dt466 if that ur choice. otherwise and im not a huge chevy fan id go dmax. its proven now to be worth it.
 

tbirdfiend281

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I see a lot of stuff being tossed around here that seems to me more like what people have heard from other people about stuff. I will talk on what I have specifically come accross with between these 2 motors.

I cant speak on the 3126. I can speak on the C7, witch is an evolution of that motor, just as the Maxxforce DT is internationals Dt466 for now a days.

now, let me talk 466s. I have seen more then a few trucks that are over 300k, and have not been inframed yet, so they will last past 150k. The 12valve non EGR motors feel stronger then the newer lot of trucks rated at the same power, no idea why, just most of those DT466E's and the DT466s I have driven in box trucks and school buses have been strong VS the Maxxforce DT generation trucks and the EGR DT466s.

When the DT's went to a 24valve set up, they do occasional have problems with failed camshafts, the lifter holder will break, then the lifter will spin around in the hole, eat the camshaft a bit, and then cause a misfire. It is a big job, and takes a lot of parts. A cam job is just an inframe minus doing the liners and pistons rings and such, so weigh in on that. The dt's will occasionally and rarely drop a valve, and then require an inframe or a motor job because metal will pump through all the cylinders and damage the liners.

The C7 I have only dealt with on MRAP applications, and for the most part, ran like champs no real failures. One thing of note, was that the Maxxpro MRAPs also run DT motors, and also I did not hear of any of those motor having failures, so maybe my C7 experience cant be taken into account. I do know, they run strong.

I would recommend trying to get a truck, witch ever motor you choose, that runs a 3000 series allison. They really wake the trucks up performance wise vs the 2000s. The transmission means business.

These 2 motors mechanically are to similar to say 1 is hands down better then another, just a preference thing, like picking a trucks color. They both have there strengths and weakness.
 

K-nite

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I own a Freightliner C7 250hp 6spd. manual with 230kmi. It has performed great so far. When I purchased it, it was a toss up between that and IH. I've driven older mechanical DT466 trucks before most were lower power ratings. The DT is a good engine with a long history, just getting choked by emissions and bean counters.

My sister in law worked at a Thomas Bus dealer doing warranty claims. Something to watch out for on the DT is the coolant condition. When they started using extended life coolant over time it eats at the sleeve O-rings. So you end up with a bus driver(mostly non mechanical) cruising along, an O-ring blows out dumps the coolant into the oil and the engine is toast. Apparently this has happened so often that they are getting serious about offering Cummins engines in IH buses. Or you can just check your coolant regularly.
 

79jasper

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^ you talking the T444E? Or the older one?

If you're talking the T444E (94+) it's the injector cup that will leak into the cylinder.

Both have oil coolers on the block that can have oring failures causing the oil/coolant mixing.

Sent from my USCC-C6721 using Tapatalk
 

tbirdfiend281

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I own a Freightliner C7 250hp 6spd. manual with 230kmi. It has performed great so far. When I purchased it, it was a toss up between that and IH. I've driven older mechanical DT466 trucks before most were lower power ratings. The DT is a good engine with a long history, just getting choked by emissions and bean counters.

My sister in law worked at a Thomas Bus dealer doing warranty claims. Something to watch out for on the DT is the coolant condition. When they started using extended life coolant over time it eats at the sleeve O-rings. So you end up with a bus driver(mostly non mechanical) cruising along, an O-ring blows out dumps the coolant into the oil and the engine is toast. Apparently this has happened so often that they are getting serious about offering Cummins engines in IH buses. Or you can just check your coolant regularly.

I am not saying this will not happen, but I have yet to see this as a DT failure. I have seen plenty of other stuff go down, like the camshaft failures on the 24valves, and I have seen where the liners will score up and the trucks wont run right, on both the 12 valves and the 24valves. If the dt's overheat real bad the liner o rings can burn up, and then you can pull the liner right out by hand.
 

tbirdfiend281

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^ you talking the T444E? Or the older one?

If you're talking the T444E (94+) it's the injector cup that will leak into the cylinder.

Both have oil coolers on the block that can have oring failures causing the oil/coolant mixing.


Sent from my USCC-C6721 using Tapatalk

Typically the injector cups failing will lead to fuel in the coolant with the t444e
 

silkyj87

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I work for a company that contracts with the US Military (we build the Stryker) My job consist of nothing but 3126 and C7 engine work as well as dyno testing every engine. I have worked on hundreds of 3126s and have only seen catastrophic failure due to solders filling the intake with water while on the wash rack. These are solid engines the only real down fall or "Achilles heal" for the 3126 is the crossover tubes for the HEUI system. They develop hairline cracks and leak off oil pressure which would be used for injection actuation. The C7 uses the same block as the 3126 but has a re-designed head which eliminates the use of the crossover tubes. There is some other physical differences but they are basically the same engine. From my experience if your looking for the power I usually see better numbers out of the 3126 than the C7 at roughly 350-375hp @ the flywheel and well over 850lbs of Tq. Our engines are calibrated for more power than what can be had on the economy. But we were told that 3126 and C7 can both be had at 325hp. Personally think they run great, and they have more than enough power to run a 60k lb Stryker thru the desert @55 mph.
 

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