If You're Buying A 5.9 Cummins, Avoid These Years -Jalopnik

[A56]

The 5.9-liter Cummins is diesel royalty. It's the reason thousands of Ram trucks from the late '90s and early 2000s are still climbing hills, pulling trailers, and terrifying Priuses in the fast lane. But here's the thing — not every 5.9 is worth your cash.

If you're eyeing a 5.9-powered Ram built between 1999 and 2001, pump the brakes. You might be staring at the infamous "53 block" — a factory-cast engine block with a known flaw -- under stress (read: doing diesel things), they're prone to cracking. Coolant starts leaking, temps go haywire, and you're left with a truck-shaped paperweight.

Even worse? Spotting a 53 block isn't exactly plug-and-play — the casting numbers are commonly tucked on side of the engine block, either on the passenger side or on driver's side. And if you find it? You're gambling. Cummins knew the 53 block was a ticking time bomb, so when they rolled out casting #54 and up, they beefed things up where it mattered.

Block cracks aren't the only trap. There's another silent killer lurking in early 5.9s — the killer dowel pin (KDP). This little metal dowel, meant to hold the timing gear housing in place, has a nasty habit of vibrating loose over time. If (or when) it falls out, it can drop into the timing gears and cause catastrophic engine damage. Think broken gear teeth, trashed camshaft, or worse — a full engine rebuild.

The issue affects 12-valve and early 24-valve engines from 1989 up to the 2002 model year. The fix? A simple KDP tab kit that locks it in place. But here's the problem; unless a previous owner installed that kit (and documented it), there's no way to know for sure if you're safe. Combine that with VP44 injection pump issues, where the rotor seizes up, and you've got a recipe for wallet pain. Cue hard starts, fuel knock, and then ... silence.

Replacements aren't cheap, and the job isn't beginner-friendly. Some trucks have replaced the original-equipment pumps with upgraded lift pumps like Fuel Air Separation System (FASS) or AirDog), but without proof, assume the worst. Toss in random engine-control module glitches and electrical bugs? That dream diesel deal starts looking more like a 7,000-pound headache.

If you're sold on the 5.9 Cummins (and fair enough, it's a beast when it's right), aim for the 2003 to 2007 model years. These trucks use the high-pressure, common-rail injection system, ditching the failure-prone VP44 for a CP3 injection pump. They're more efficient and, most importantly, far more reliable. Of course, basic diesel maintenance will keep the mill churning for longer.

 

[tjpatte]

I had a 1998.5 24 valve with the 53 block. The first half of 98 was the 12 valve that still had the KDP, however the 24 valve in the second half did not.

Ran a TST Powermax 3 with 100HP injectors and never damaged the block, however I did manage to snap the input shaft on a NV4500. My biggest issue was lift pumps, went through about 6 of them in 175K then bought a FASS pump that mounted in the stock Carter spot.

The truck is now living in Idaho with my buddy and his 24 valve with no issues.

 

[MopaR&D]

Not to be a dick to the OP but typical clickbait Jalopnik article written by someone who doesn't really know the content in the article. 53 blocks should be avoided but they aren't guaranteed junk, just don't go crazy cranking up the power. KDP is not all that hard to check, everyone who's into 12-valves knows about it. Similar story with VP44 pumps, they aren't great and have issues but if you upgrade to a high-capacity lift pump and run lubricity additive in the fuel they run for a long time. Worst case you just convert to mechanical setup like a P-pump or even VE pump. In recent years guys have figured out how to build VEs get 600+ HP.

 

[A56]

Not to be a dick to the OP but typical clickbait Jalopnik article written by someone who doesn't really know the content in the article. 53 blocks should be avoided but they aren't guaranteed junk, just don't go crazy cranking up the power. KDP is not all that hard to check, everyone who's into 12-valves knows about it. Similar story with VP44 pumps, they aren't great and have issues but if you upgrade to a high-capacity lift pump and run lubricity additive in the fuel they run for a long time. Worst case you just convert to mechanical setup like a P-pump or even VE pump. In recent years guys have figured out how to build VEs get 600+ HP.

lmao, whether or not you're being a dick is not for me to judge. However, articles like these are not written in stone and obviously it does have some merit and invites objective comments from folks with experience on the subject. That's what these forums are for lest you forgot.

 

[crackedback]

The "avoid these years" is the rub for me. No need to avoid them. The article title is garbage IMO.

Buying a 5.9, know your subject.
Helpful hints and what to look out for on this generation cummins.

But that isn't clickbait. All good points in the article.
The killer dowel pin is a pretty easy fix. If you have a TIG handy, you can get away without busting cover completely off!

I could write an article about 7.3 Powerstrokes and avoid these years... they are solid engines with some quirks, same as cummins. I wouldn't avoid any of them, nor tell anyone the same.

Avoid all blondes, these years are raging bitches. Same approach.

 

[A56]

The "avoid these years" is the rub for me. No need to avoid them. The article title is garbage IMO.

Buying a 5.9, know your subject.
Helpful hints and what to look out for on this generation cummins.

But that isn't clickbait. All good points in the article.
The killer dowel pin is a pretty easy fix. If you have a TIG handy, you can get away without busting cover completely off!

I could write an article about 7.3 Powerstrokes and avoid these years... they are solid engines with some quirks, same as cummins. I wouldn't avoid any of them, nor tell anyone the same.

Avoid all blondes, these years are raging bitches. Same approach.

I think that would be avoid all blondes within a certain age actually.