Even the most legendary engines weren’t perfect. Jeep 4.0 with the early 2000s first revision 0331 head. 24 valve Cummins and the TUPY 53 block. 12 valve Cummins with the dowel pin. Ford 300 straight six with phenolic timing gears that didn’t age well. Great engines can still have big design flaws. The difference is knowing it before it costs you an engine. What other “bulletproof” engines had built in flaws people forget about? #engine #diesel #mechanic #automotive #trucklife #carfacts #enginee