Will a 1998 Dodge Durango 5.9 engine fit in 2003 Durango?

While both are Dodge Durangos and share some similarities, a direct swap of a 1998 5.9L engine into a 2003 Durango isn't a simple bolt-in affair. There are significant differences between the two model years that will create compatibility issues. You'll likely encounter problems with:

* Engine Management System (ECM/PCM): The 1998 engine uses an older engine control system that's incompatible with the 2003's wiring harness and computer. You'd need a significant amount of rewiring or a custom harness.

* Wiring Harnesses: The entire wiring harness will be different, requiring extensive modification or replacement.

* Sensors: Sensor locations and types may differ, requiring further modifications.

* Exhaust System: The exhaust system might not line up perfectly.

* Transmission Compatibility: While both might be automatics, the transmission compatibility needs verification. You might need to swap transmissions as well.

* Mounting Points: While the general engine bay layout is similar, there might be subtle differences in mounting points that could cause issues.

In short, it's a very complex undertaking requiring significant mechanical knowledge, specialized tools, and likely custom fabrication. It's far from a straightforward swap and would probably be more trouble than it's worth unless you have extensive experience with engine swaps and are prepared for significant challenges. It would likely be cheaper and easier to find a replacement 5.9L or a different engine that's compatible with the 2003 Durango.