Opinions on Cummins 5.9 Diesel

[Builder]

Didn't think there would be any negative comments in a 5.9 thread

Even on those viscous truck forums no one ever bashes Cummins.
I had a 95 12 valve in a 2500, low miles but 13 years, the greatest engine ever made in it's class period.

The 4th generation 6.7L ain't no slouch either, I've got one in a 3500 with a Aisin tranny (180,000 mile warranty!) Only time will tell if it can live up to it's little brother as far as longevity goes, probably not due to all the mandated emissions crap but man it is a sweet ride!

JB.

They're great engines, but not perfect. 53 block & killer dowel pin come to mind. Many years in front of awful automatic transmissions, death wobble in the steering, etc.

If the 12V was on an engine stand, other than 53 & KDP, it would be a work of art. Thing is, we drive trucks, not engines.

All that said, it's my fav diesel for a pickup. DMAX is a very close second place.

 

[JB4310]

They're great engines, but not perfect. 53 block & killer dowel pin come to mind. Many years in front of awful automatic transmissions, death wobble in the steering, etc.

If the 12V was on an engine stand, other than 53 & KDP, it would be a work of art. Thing is, we drive trucks, not engines.

All that said, it's my fav diesel for a pickup. DMAX is a very close second place.

No maybe not perfect, that 53 block thing only affected a fairly small number of vehicles and never heard of any that caused catascopic engine failure. The KDP issue was more common, I never did anything with mine but warned the guy who bought my truck that he should look into it. Hate to see such a little thing cause such a big problem.

I had my own issue, in the picture you can see I had to rebuild the Bosch pump, Don't know why just had lose of power, brought it to Cummins shop and they told me I needed a new pump. $2500. I often wonder if I didn't get taken, the truck only had 40,000 miles at the time. That was the only problem in 13 years so comes out to less than $200. a year and 3 days down out of 13 years!

JB.

 

[waldersha]

I never considered myself a Dodge guy, had GM and Fords before getting this one. That was 10 years ago. I did buy mine for longevity, mileage, and just because I needed a truck. Several others have said that the engine will outlast the body, and I know that to be true, but I can't imagine driving anything else now.

I've replaced the starter once and the lift pump. Other than that in 10 years it's just been regular maintenance stuff. Can't complain. Brother has driven Ford diesels (notice plural) for years, dad has had both Ford and Chevy diesels, neither can compare with mine for reliability, mileage, or just down and dirty outright grunt. Oh and one other thing, NO GLOW PLUGS! That right there in my opinion makes it a superior engine. Have not once had a fail to start in the cold.

 

[Builder]

I never considered myself a Dodge guy, had GM and Fords before getting this one. That was 10 years ago. I did buy mine for longevity, mileage, and just because I needed a truck. Several others have said that the engine will outlast the body, and I know that to be true, but I can't imagine driving anything else now.

I've replaced the starter once and the lift pump. Other than that in 10 years it's just been regular maintenance stuff. Can't complain. Brother has driven Ford diesels (notice plural) for years, dad has had both Ford and Chevy diesels, neither can compare with mine for reliability, mileage, or just down and dirty outright grunt. Oh and one other thing, NO GLOW PLUGS! That right there in my opinion makes it a superior engine. Have not once had a fail to start in the cold.

Lots of diesels don't have glow plugs! But intake grid heaters can fail, too.

Simple is the best. You oughta see my DTA 466 looks like a tractor engine in a truck engine bay!

 

[waldersha]

Lots of diesels don't have glow plugs! But intake grid heaters can fail, too.

Simple is the best. You oughta see my DTA 466 looks like a tractor engine in a truck engine bay!

Agreed, but in the "big 3" the Cummins is the only one without Glow Plugs unless they've changed that on the newest ones. You are right, simple is the best.

 

[WH401]

Agreed, but in the "big 3" the Cummins is the only one without Glow Plugs unless they've changed that on the newest ones. You are right, simple is the best.

Nope there still there, it's nice not having to worry about changing plugs. Even if the intake heater does go out, it's a simple one area fix, unlike a glow plug.

 

[WantedWolf]

How did this one slip past me? Im really late to this thread and might not get time to read it all. But...

I wanted to mention when I saw this, My 01 cummins is now sitting at 350330km I got a 'deal' on it. with many labour hours and much $'s to make reliable.
now my 1989 toyota 4RNR cost $700 + $40 u joint and $60 rear brakes.
She is sitting at 354000km (5spd Gasser) And this is my beater
4x4 'farm truck' at least those last 30k km have been brutal on her little 4cyl. Hauling large round bales, pulling a stuck cummins ram 3500 and its always hauling the big 40 trailer. This thing still runs strong, no rebuilds.
So I vote (as always) toyota is the acception to the rule at least the 22r/e

I do know that diesels will outlive gasoline engines, that is proven fact. The thing I do not get is why that is important for most of the population that own a truck. Most people never never run a diesel for that 300K or 500K miles, they trade them in way before that.

About the cummins tho, I still wish I waited for a p/u with the 12v 5.9
Althought I can only compare with my friends 12v non GN service body truck.

-The 24v or ISBs are famous for VP44 death (inj pump failure) mostly caused by a failed transfer pump or over heated computer.

Best thing I ever did for the truck and my driving style was to install gauges to get the real info, Dodge does not put enough gauges on the dash, to match the 7million sensors the put under the hood. I recomend a Fuel pressure gauge (maintain above 7psi) . A pyro gauge (keep below 1200)
A boost gauge (skip the vacuum, never see it move) and a tranny temp gauge. I think the TT gauge helped me make it home last trip, had I not installed it I would have kept pushing the truck and might be writing how much fun it is to swap a tranny.

And I guess I could mention I did have 350000km on my 1997 f350 gasser. But now we can all forget I ever had a ford.

 

[Renze]

The 4th generation 6.7L ain't no slouch either, I've got one in a 3500 with a Aisin tranny (180,000 mile warranty!) Only time will tell if it can live up to it's little brother as far as longevity goes, probably not due to all the mandated emissions crap but man it is a sweet ride!

The 6.7 is just a QSB 5.9 with its stroke changed from 120 to 132 mm.
I really wonder if the higher piston speed (compared to the V8 duramax or any gasser), as a result of the long stroke, combined with 3500 rpm in PU truck duty, will do to this engines life expectancy... ???

Long stroke engines need to do it from down below, not hit high rpm.

 

[QRTRHRS]

Nope there still there, it's nice not having to worry about changing plugs. Even if the intake heater does go out, it's a simple one area fix, unlike a glow plug.

Usually, the relay's for the grid fail. You can pick up a couple of replacements from Allied Electronics for around 14 bucks each along with fabing up a new bracket to hold them. Much cheaper than a glow plug.

Everyone knows about the dowel pin but a lessor known issue is that the cap screws holding the inner timing gear cover can also vibrate out. That happened to my former neighbor's 92'. Took the timing gear right off of the cam. Never hurt the valves but a few years later the head cracked on it. Don't know that it was connected or not. Stock engine and he never beat on it.

Eh' Builder, the death wobble is a Mopar issue not a Cummins. Easily fixed with a number of aftermarket cures. Of course the automatic transmission is a Mopar issue as well and easily but not cheaply fixed. Nor, is the 5speed with out it's problems, ie; loosing fifth gear. Of course, easily fixed (ha) with an after market fully splined shaft.

IMHbiasedO, the Cummins will last longer than a PS or a DMAX. But, the more you know about what makes this engine tick as well as the Dodge truck the better off you will be. Otherwise, you will be at the mercy of your dealer. More often then not, there are better and less expensive replacement parts.

 

[Builder]

Usually, the relay's for the grid fail. You can pick up a couple of replacements from Allied Electronics for around 14 bucks each along with fabing up a new bracket to hold them. Much cheaper than a glow plug.

Everyone knows about the dowel pin but a lessor known issue is that the cap screws holding the inner timing gear cover can also vibrate out. That happened to my former neighbor's 92'. Took the timing gear right off of the cam. Never hurt the valves but a few years later the head cracked on it. Don't know that it was connected or not. Stock engine and he never beat on it.

Eh' Builder, the death wobble is a Mopar issue not a Cummins. Easily fixed with a number of aftermarket cures. Of course the automatic transmission is a Mopar issue as well and easily but not cheaply fixed. Nor, is the 5speed with out it's problems, ie; loosing fifth gear. Of course, easily fixed (ha) with an after market fully splined shaft.

No doubt, my friend. I just thought it worth mentioning that Dodge/Cummins trucks are nice under the hood, but they have other issues in the remaining parts of the truck the other 2 don't seem to have. They cost money to fix, too.

Unforunately, there's no perfect truck. Ford-engines are weak, Dodge-quality issues, GM-HD suspension is lagging behind Ford.

It's really pathetic that none of their truck engineers will read these baords and upgrade some of their weaknesses. GM would seem to be a real easy fix. All it would take is a Dana front axle. Probably save quite a bit of money for customers, too.

IMHbiasedO, the Cummins will last longer than a PS or a DMAX. But, the more you know about what makes this engine tick as well as the Dodge truck the better off you will be. Otherwise, you will be at the mercy of your dealer. More often then not, there are better and less expensive replacement parts.

True because there's so much less moving parts. Hey, I'm a 6-banger guy too. I have a DTA-466 and I know how you feel about simple 6 cylinder diesels. They have a tourqey feeling when they're pulling that you can't appreciate until you drive one.