Another XJ engine replacement thread

My current motor in my 98 XJ has what I assume is 240k on the original engine. I'm losing some coolant through what I think is a head gasket or cracked head, plus it's got a significant exhaust leak and leaks a little oil. I don't want to go chasing issues on a high mile motor so I thought I'd try to find a replacement under 180k. I'm only interested in long blocks, as I want the swap to cheap and easy.

ZJ motors seem easier to find locally. Didn't the 4.0s get changes to the castings in 96 to help with NVH? What year motors and from what vehicles would be a direct swap?

They changed the block for WJ and later TJ. ZJ engine is the same but you need to swap everything attached to it, all ignition parts, fuel parts, sensors, pulleys, brackets, everything.

The water pump was different on the TJ motor I got as well.

I'll be replacing the water pump and seals before it goes in. So for a plug and play, 96-98 XJs are what I'm looking for? Otherwise I'll have to reuse most of my accessories?

Not exactly. Some of the sensor plugs are different between all those years. You may have to swap out a couple of your stock sensors for the donor motors'.

The layouts are different. XJ is the only one with two fans (offset mech fan pulley), while the others have a big fan in the center (center mech fan pulley). Exhaust routing is different on wranglers and exhaust manifold is different. Power steering setups are different. Etc.

Even in XJ there are differences in fuel rails, ignition setups, throttle body setups, etc

The further you get from same model and year, the more stuff you have to swap