I’ve always heard that 100k miles is just breaking in a V8 diesel. Does the same logic apply to the 3L inline-6 diesels in half-ton trucks? Are they built to last the same way?
Are you asking if the diesel engines in half-tons are as durable as the ones in 3/4-tons?
Generally, no. The 3/4-ton diesels are designed for higher workloads and tested for longer lifespans. They’re also used in commercial vehicles, which demand more durability.
The half-ton diesels, on the other hand, are usually the biggest vehicles those engines are used in. For example, the F150 diesel originated in Jaguar and Peugeot sedans, and the Ram 3.0L V6 started in Grand Cherokees and Chrysler 300s. They’re good for typical half-ton use, but if you’re towing heavy loads, they’ll wear out faster than a 3/4-ton engine.
That said, some older 3/4-ton engines, like Ford’s 6.4L, were less reliable than today’s half-ton diesels. It really depends on the engine and how it’s used.
@Dru
I wanted a 6.4 until a mechanic told me that engine was putting his kids through college.
Paris said:
@Dru
I wanted a 6.4 until a mechanic told me that engine was putting his kids through college.
The 6.4 has a lot of known issues, but there are fixes for most of them. If you get the truck cheap enough and plan to keep it long-term, fixing a 6.4 can be worth it.
Paris said:
@Dru
I wanted a 6.4 until a mechanic told me that engine was putting his kids through college.
Between the 6.4 and the 6.0, I bet he stayed busy.
@Dru
I don’t know much about Ram. Are the two diesel options in the 2500 and 3500 the same engine?
Fox said:
@Dru
I don’t know much about Ram. Are the two diesel options in the 2500 and 3500 the same engine?
They’re just different trims of the same engine.
The 6.9 and 7.3 were used in International buses and trucks. They were built for medium-duty work, which is why they’re so robust.
Hollis said:
The 6.9 and 7.3 were used in International buses and trucks. They were built for medium-duty work, which is why they’re so robust.
As a UPS driver, I’ve seen how well these engines hold up. We’re phasing out our diesel trucks, but many of them reached 700k-800k miles with only two engine replacements. That’s with bare-bones maintenance, so it says a lot about their reliability.
@Quincy
The Cummins in pickups isn’t the same as the one in those bigger trucks, though.
Hollis said:
@Quincy
The Cummins in pickups isn’t the same as the one in those bigger trucks, though.
Isn’t the fuel pump the only difference?
Hollis said:
@Quincy
The Cummins in pickups isn’t the same as the one in those bigger trucks, though.
Isn’t the fuel pump the only difference?
It’s not the same engine, and you’d be lucky to tow 20,000 lbs with the pickup version.
Diesel engines in HD trucks are way overbuilt compared to the ones in half-tons. They’re made to last a lot longer.
Cummins inline-6 engines, like the 5.9 and 6.7, were originally designed for commercial use, so they’re built tough. V8 diesels aren’t inherently better for longevity since they have more moving parts. Inline engines are generally more efficient and durable, but emissions equipment has made all modern diesels less reliable than older models.
@Leith
The Cummins design is robust because it was intended for heavy-duty applications, like buses and trucks. The inline-6 layout is also simpler and easier to work on compared to V8s. That’s why most semis use inline engines.
@Leith
V8s are often used because they fit better in smaller engine bays. Inline-6s need more space.
Kelly said:
@Leith
V8s are often used because they fit better in smaller engine bays. Inline-6s need more space.
I think V6s and V8s are chosen for front-wheel-drive setups in cars because of packaging, not necessarily because of space concerns in trucks.
Most V8 diesels in pickups don’t make it to 100k miles without some kind of major issue. Half-ton diesels, like the 3.0L inline-6 in the Silverado, are lighter-duty engines. They’ll last a while, but they’re not built for heavy towing. That’s why I prefer the inline-6 design for durability.
@Flynn
That’s not true at all. Plenty of V8 diesels last past 100k with no major problems.
@Flynn
The 7.3L Powerstroke V8 was one of the most reliable diesel engines ever made. V8s aren’t inherently bad; it depends on the design.