[SundevilYJ]

I have a 98 TJ 4.0L auto and I have just replaced my water pump because it was slowly leaking out of the weephole.(lasted 72k) I bought the new water pump from Checker Auto, is was a brand new Cardone. After I installed it and filled the system up with coolant, it overheats. The thermostat was replaced last week and worked fine. After I run it for a few minutes, the thermostat opens, but I think the flow of the coolant is backwards?? There isn't any coolant flowing into the lower radiator hose from the water pump?? I called checker and a jeep dealership to find out if there are different versions of water pumps, the both said they make only one version and they are all reverse rotation pumps - the new one from checker did not have an "R" stamped on the back like the stock one. Also, before putting the new pump on I checked the direction of the fins on the impeller and it matched the direction of the old one. Is the new water pump bad or the wrong one?

[jeeptj19992001]

sounds like a air bubble is in the block

[KUK9]

I agree. Did you burp the system before you started driving it around? My guess is you have a big air pocket in there.

[JBTJ]

Like said, possibly air in the system. There should be a small hole in the thermostat. You want it located in the 12:00 position when it is installed. This will allow air to escape. If there is no hole you can drill one about the size of pencil lead in the housing, or get on that has the hole in it.

[SundevilYJ]

How do you burp the system?