[StokedXJ11]

This is the directional flowing of coolant in the cooling system, taken from the 1997 XJ FSM.



Now my question/ concern is about the heater hoses. There is a upper and a lower coming out of the heater core, according to the picture the upper is the outgoing while the lower is the in going coolant flow. In the picture the upper(outgoing) hose connects respectively to the bottom of the water pump, and the lower(incoming) hose connects respectively to the upper part of the water pump. So basically they kinda crisscross. Ok now that i am done explaining to yal what you already know or can depict from the picture.

My hoses do no do this. The upper hose coming out of the heater core goes to the top of the water pump and the lower hose goes to the bottum. So why are they different from the FSM? Does anybody know which direction the coolant is flowing through those hoses? Which one is flowing in to the heater core and which one is flowing out?

Edit: Sorry that pic is a little to small ill see if i can resize it
Edit x2: There ya go its bigger and easier to see now.

[conrasm]

Do you have a heater control valve? I eliminated mine and ran hoses like the diagram, but I can't remember if mine criss cross like that one. I do know that there are two sizes of hoses on mine. The t-stat and one of the heater core inlets is 3/4" while the water pump tube and the other heater core outlet are 5/8", so I just ran it that way. The direction of flow through the heater core won't matter.

[dyna]

Without one sitting in from of me I`ll guess if you look at the H20 pump you might be able to tell which is the output side or outlet based on location of the heater output/input nipples and the impeller cavity. Yours could be switched ? One way to tell for sure is gently pull both hoses off the core and hold em up above the engine about a foot then fire it up and see which spews coolant and hook that one to the bottom of the core.

[StokedXJ11]

Originally Posted by conrasm

Do you have a heater control valve? I eliminated mine and ran hoses like the diagram, but I can't remember if mine criss cross like that one. I do know that there are two sizes of hoses on mine. The t-stat and one of the heater core inlets is 3/4" while the water pump tube and the other heater core outlet are 5/8", so I just ran it that way. The direction of flow through the heater core won't matter.

Heater Control Valve? Im not sure if i do or not.....

I just checked the hose that goes from my T-stat to the heater core(upper) is 11/16" not 3/4". So i am assuming that this tells me someone has done work on the cooling system of my Jeep?

With the T-stat taken out, If i were to pump water into one of the heater hoses the direction of flow doesn't matter to flush the system?

[AZ Jeff]

A 97 XJ does not have a heater control valve, and coolant circulates through the heater core all the time. The diagram you are shown in your manual is the correct routing for the hoses. The inlet to the heater core is the lower hose, and the outlet is the upper hose.