The most prominent failure point for the Cummins 6BT and the first-gen ISB 5.9-liter diesel engines is ... to 400,000 miles on the odometer are common on internet forums and respectable sources ...

For many 5.9 Cummins owners, upgrading to a premium valve cover can make a significant difference in engine performance. John, a long-time Cummins truck owner, began experiencing oil leaks and a ...