diesel pusher engines

5 Worst Diesel Pusher Engines to Stay Away From

Diesel pushers are better choices than gas-powered motorhomes because of their raw strength and horsepower. However, there are still some diesel pusher engines to avoid because they are simply not worth your money.

Now, don’t get me wrong. Diesel engines do offer rugged dependability, but not every model is created equal. There are certain ones that have gained less-than-stellar reputations over the years for troublesome issues and high maintenance costs.

Worst Diesel Pusher Engines to Avoid

I’ll be shedding some light on some diesel pusher engines to avoid. The brands of these engines are not bad at all. They have some excellent models in their lineups. However, these particular engines failed to impress.

International VT-265 and VT-335

If you’re considering an RV with an International VT-265 or VT-335 diesel pusher engine, think again. Those four-cylinder units simply can’t deliver the power needed to tow large trailers with confidence.

Downsizing those long-running International diesel designs from six cylinders to four was a mistake because those engines strain under the load. You’ll find them noticeably underpowered for passing and highway driving while towing. Struggling to maintain speeds up steep grades or with crosswinds will add unnecessary stress.

Compared to the company’s previous six-cylinder models, the VT-265 and VT-335 also need more frequent repairs. Everything from sluggish performance to premature component wear suggests those engines weren’t robustly built to handle RV duty cycles.

If you want to avoid the hassle of unreliable operation over the long haul, don’t buy these models.

Cummins ISX

The ISX sounds impressive on paper, but in practice it proved to be overly complicated and problematic. When it was introduced back in the early 2000s, Cummins touted it as their new top-of-the-line model. But the dual overhead cam design ended up being more trouble than it was worth.

All those moving parts gave the engine too many things that could go wrong. I’ve heard stories of ISX owners dealing with an endless string of expensive repairs, including broken camshafts, worn injectors, faulty EGR systems, etc. The electronic controls were glitch-prone too.

It’s a real shame because Cummins had built their name on tough, no-nonsense diesels. The ISX was supposed to take them to the next level, but the excessive electronics and finicky design just caused problems. I’d avoid one if you’re looking for a diesel pusher.

Cummins introduced a new version of ISX to the market in 2010. It had a simpler design featuring a single overhead. However, people already lost their faith in this model, so it didn’t sell well.

Cummins ISX engine. Image Credit: Panoha/Wikimedia Commons

Caterpillar CAT 3116

CAT 3116 is another name in my list of the diesel pusher engines to avoid. Working on that thing would be a major pain. You’d constantly need special tools just to do basic maintenance, and those tools are available only at Caterpillar. Also, these are expensive tools that can easily cost over $5000.

Another major downside is that the engine doesn’t have much power compared to other options, like a Cummins. When you factor in the cost of all the tools and replacement parts, it becomes a real money pit.

Newer CAT engines like the 3126 and C7 are supposed to be better bets. But if you can avoid the 3116, I’d suggest looking at other brands that are easier to work on yourself.

Navistar MaxxForce 13

This engine seemed to always be breaking down, requiring you to spend more time at the repair shop than on the road. Driving with this engine feels like you’re always waiting for the next problem to pop up.

The MaxxForce 13 just couldn’t seem to handle the strain of its emissions system. Something was always going wrong with the EGR and DPF, which are important parts for keeping diesel engines clean. Navistar never really figured out how to make that high-flow EGR system work reliably. You’d be lucky if you went more than a few months without a major repair bill.

Also, this engine was known for burning through its aftertreatment system really quickly. You’d be replacing expensive parts left and right to try and keep it passing emissions tests. I’d steer clear and consider another brand if you want an engine you can depend on.

Detroit (Old two-stroke Series 50, V-71, V-92)

The Series 50, V-71 and V-92 may seem like decent options since they’re simple to work on, but trust me, the technology in those things is way past its prime.

Parts will be a nightmare to find for those ancient Detroits, and something is bound to break down and leave you stranded. Plus, the fuel efficiency must be terrible. You’ll spend a fortune just putting diesel in the tank.

If you want reliability, go with something made in this decade. Newer is definitely better in the engine department.

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