This is my first post so I hope I'm doing this right. I've had my jeep for 6 months. It's an 02 GC with a 4.0 straight 6. When I bought it it wasn't knocking, now it is. I drive it 3 hours to my parents and found out it was a rod bearing, lucky I know. So we bought a used engine and my dad and uncle are swapping them while I came back home. When they started to tear into it, they said it had 2 fans. The one I know connects to the engine but the other I'm not certain where it came from as I wasn't there when they took it apart. My question is, are they supposed to have 2 fans? My dad seems to think it would cool better without the second fan and just the one that connects to the engine. I'm not sure if it is supposed to be there, or if someone put it in there. Any information would be helpful as we have the engine and are putting it back together and hopefully I'll have my jeep back. Dad also wants his truck back I'm borrowing lol thanks. I'll add a few pics of what dad has sent me of the parts. The one we're unsure of
Fan and clutch
New engine going in

 

Top fan is the correct fan for your GC. Bottom fan came off the used motor.

 

Welcome to CF!

Actually, both fans were probably used on the 2002. 99 had both because they weren't sure the electric one would keep it cool enough. My 2000 only had the electric one and if the relay stops working, which is commonplace, the engine overheats immediately. Most WJs with the tow package had both anyway. I would say having both is good insurance against an overheat. The clutchfan doesn't perform adequately in heavy traffic at slow speeds, so I wouldn't rely on it only. JMHO however.