no heat

[delverde]

88 xj 4x4 4.0 auto
heats not working put in a 190 deg. thermostat about a month ago when i installed a new water pump do you think its the heater core and how hard is it to install ? When i turn off the jeep after about 30 sec. i hear a vent door close is this normal? all i have is cold air at 190 deg.coming out of the bottom vents.

[RichP]

Are the hoses going into the heater core [the ones alongside the motor] hot ?
Does the engine reach operating temp ?
If the engine reaches operating temp and the hoses going into the heater core are cold then I would guess it's the mixing valve. Could be the valve itself or the temp control is not hooked up, the one that goes from cold to hot on the dash.
I had a Trooper that would not get warm on bitter cold snap, at 8am I was out in a parking lot of a parts store at -5F 6 miles from the house replacing the tstat, somehow a piece of tywrap or wiretie had gotten wedged in and would not let the tstat close, not a clue by any stretch of the imagination how that piece of tywrap got in the cooling system.

[husker25]

I've heard people installing the t-stat backwards--but then the motor does not heat up to normal operating temp so this may/maynot be any help to you. Just a thought.

[AlohaBra]

Disconnect the heater hoses and see if the heater is not plugged.

Use a water hose and flush it out.

88 XJs have a heater valve on the liquid side and ...BTW, the core is a bitch to change.