What Year Did Cummins Have A 53 Block? (And How To Tell If Your Engine Has One)

Cummins has been one of the most respected names in the diesel engine game pretty much since the moment the company began manufacturing diesel engines. And that is saying a lot, as the Indiana-based company has been designing and manufacturing diesel powerplants for more than a century. 

Over that span, Cummins engines have been utilized to power everything from automobiles to boats to long-haul trucks. Since 1989 they've also been featured prominently in the celebrated Ram pickup truck line. Cummins engines have been well loved by Ram drivers over the years, with the manufacturer's Ram 6.7L model even ranking among the most reliable diesels ever made. But not all the manufacturer's diesel engines have been so beloved. In fact, roughly a decade after Cummins began outfitting trucks bearing the Ram badge with engines, it delivered one of the worst diesels in its history, the so-called "53 Block."

The notoriously dodgy engines were offered in Dodge Rams between 1999 and 2002, and the 5.9L 24-valve builds are feared by many Ram aficionados due to a design flaw that ultimately leads the block to crack, leaving coolant to leak out. As is typically the case with such issues, the leak will only get worse over time, and eventually lead to engine failure. The ensuing damage will leave owners facing a pricey repair that could cost anywhere between $5,000 and $10,000. Thankfully, there is a way to identify a 53 Block Cummins engine if you're determined to avoid one. 

The model year of your Dodge Ram is, of course, the easiest way to determine if the truck might be powered by a 53 Block Cummins. If you know that the Ram in question was manufactured between 1999 and 2002, and is, in fact, powered by a Cummins diesel engine, there's one more identifying mark to look out for to confirm that it's packing a 53 Block. Said identifying mark is the casting of the number 53 directly onto the engine itself. That number is typically located on the front of the engine on the driver's side.

If you find that identifying insignia on your engine block, logic might dictate that you simply walk away from the vehicle and save yourself the headache of dealing with the engine-destroying design flaw. If you're undeterred, you'll no doubt want to give the engine a close inspection to determine if the block is already cracked and if there's any coolant leaking out.

If the damage is there, the smart play may be to simply replace the 53 Block with a more reliable Cummins engine. But there are measures you can take that might keep the engine functioning over the short term, including block stitching or stitch welding the crack. Even still, those are only temporary fixes, because when a 53 Block starts to go, there's seemingly not much you can do to stop it. Consider yourself warned.