briefly,

98 xj 4.0 150k

barely has heat. if its like 55-60 out, the heat gets relatively warm, but anything lower than that, forget it. lukewarm at best, but mostly just cool air.

now i was hoping it would be a clogged heater core. i haven't flushed it yet, but i felt the rad hose, and the two heater core hoses, and their all damn HOT. so do this rule out clogged core? should i bother with the back flush?

what else could it be?

note: no leaking coolant into cabin, and no loss of coolant

 

If the core is clear, it might be a problem with the blend door

I'm not sure about a 98, but my 96 also has a vacuum controlled valve on the heater hoses

 

Yep, time to look at the vacuum controlled blend door.

 

The Blend Air Door on a '98 is mechaniclly operated via a push-pull cable controlled by the Temperature Control **** on the climate control panel. The cable connects to the Blend Air Door Crank Arm. There's a Tension Band that keeps 'tension' on the cam on the Crank Arm.

Position yourself in the passenger footwell and look forward and to the left under the HVAC Unit, there you will see the Crank Arm assembly. Turn the Temperature Control **** stop-to-stop while watching the action of the Crank Arm, and see if any parts are missing.

 

Pic of the '98 Blend-Air Door mechanism at the bottom of the HVAC Unit:



Pic of the cable attachment at the Climate Control Panel:

 

okay so i turned the temp from cold to, and back, and watched under neath. i did it quick, so ill check again later, and post a video. but what i saw, was that when i would switch the temp from one end to the other, the little white screw looking thing would rotate.

is that all that i am looking for, or is there a particular part i should pay attention to

 

Look at the pic I just posted.

Make sure all the parts are there.

 

Will do, then ill get back to you.