What Is The Killer Dowel Pin Cummins And Which Years Were Affected?

Since its 1919 founding, Cummins has earned a reputation for designing and manufacturing car, truck, and SUV engines as powerful as they are reliable. Of course, if you're familiar with the Cummins name, you know the Indiana based manufacturer has particularly excelled in the diesel engine arena. Alongside its gas-powered counterpart (the storied HEMI), Cummins diesels have even become the engine of choice for many Ram pickup truck owners.

Of the Cummins diesel engines that have been utilized to power a Ram over the years, fans tend to agree that the company's 5.9 Liter 12 and 24-valve builds rank among the best to ever bear the Cummins logo. While the first- and second-generation versions of those builds are particularly celebrated, it's worth noting that those engines are far from flawless. In fact, many have been plagued by a pesky design issue that can cause the dowel pin inside the engine's timing gear house to fail, which in turn can result in irreparable engine damage.

The issue has been such a problem, it's actually been given a rather villainous nickname — the Killer Dowel Pin (or KDP for short). If you don't know what the dowel pin does, it's inserted into the block to keep the timing gear housing lined up with the engine. In the noted Cummins builds, the pin is not secured on either side, allowing it to loosen over time. When it inevitably falls out, the pin can become lodged in the housing, causing catastrophic damage.

While both the 12 and some 24-valve Cummins 5.9L engines are known to suffer from the killer dowel pin issue, it's believed that the former models are more prone to experience the problem. But it should go without saying that if you currently have a vehicle with either of the problematic engines, you'll want to address the potential dowel pin issue as soon as possible to avoid engine damage. That list reportedly includes Cummins 5.9L engines manufactured between 1989 and 2002.

There is some good news for those whose vehicle utilizes one of those engines, in that the KDP is a well-known issue, and therefore easily addressable. If you're handy under the hood, you may even be able to fix the problem yourself, with companies now making kits designed to keep the deadly dowel pin from moving. The repair will not be overly expensive for the DIY set either, as a replacement dowel pin for an afflicted Cummins engine will only set you back about $8.99 these days from Amazon, and full repair kits are available from anywhere between $65 to $136.

Now for the bad news, which is that if you can't replace the dowel pin on your afflicted Cummins engine yourself, the repair may be considerably pricier, as it is regarded as a labor intensive project. As such, goes without saying that anyone looking to buy a vehicle with a 5.9L Cummins from the noted years will want to ensure the dowel pin repair has already been conducted before purchase.