89 XJ 4.0 water pump

Are there 2 different water pumps made for right hand drive & left hand drive 4.0 models? Just installed a new water pump in a 4.0 LHD. Engine heats up excessively at idle, at the same time the heater output is quite cool like maybe low water flow. Things improve at higher rpm, like 2k & up. It acts like the pump impeller is turning backwards.

Should spin the same regardless. What's the thermostat look like? Is it air locked??

As far as I know, the RHD water pump casing is slightly different to the LHD. How exactly, I don't know but I have been cautious to get the correct replacement part following my friend's experience.


My friend Dave had a 1993 UK model RHD 4.0L similar to mine. His Jeep suffered a failed water pump when we were up one of the French Pyrenees mountains some years ago. We towed his Jeep to a local French garage/workshop and they ordered a new water pump which arrived the next day. The pump ordered was for a LHD EU model and it didn't fit, the garage had to source a RHD specific pump and my friend lost a couple more days of wheeling on that foreign expedition before the correct water pump arrived.

gdavis said:

Engine heats up excessively at idle

Click to expand...

Is your viscous fan clutch still good?

New thermostat installed also, I can see it working, opening & closing on the temp. gauge at higher rpms. Fan clutch appears ok, heater hoses feel cool at idle which makes me feel like it's a water volume issue. I just assumed that because the heater is on the opposite side with RHD, the heater hose output would be on the other side of the water pump and the vanes would angle towards that output. Which likely would take a different pump than the LHD.
Thanks for your answers and help.

Any chance you may have gotten a pump for the old 4.2L (258) instead of for a 4.0? The belt routing on the old 258 spins the pump opposite to what the 4.0 does.

Note post #4 here: https://www.naxja.org/forum/showthread.php?t=956889&highlight=water+pump+reverse+impeller

Issue identified. The heater hoses which also feed the coolant tank were reversed. So the water pump was trying to push coolant into the tank all the time and it never would siphon back into the engine as it cooled.

Wow, never had that particular issue haha. I was gonna ask if you drilled the tstat or burped the system. Those early models are picky about such.