The heat in my 1992 Jeep Wangler is not working.

flushing a cooling system is the same method as any other motor

do it without the thermostat fitted
or water pump opening

sacrifice an old radiator hose to adapt a garden hose fitting
for radiator flush

air in system fix
your thermostat housing has no air bleed valve
no top radiator cap

old school way
heater on full
run motor till thermostats fully open
burp radiator hoses
wait till water is running up into over flow bottle without bubble
replace cap
turn off heater
correct level in over flow bottle

why still over heating
you fitted everything i would have ... yet still overheat
possibles
leaking inlet manifold gaskets
hose clamps loose
cooling fans spinning too slow
thermostatic fan switch faulty
aluminum radiator is a big one
air ..fins bent or some water channels blocked

or possible head gasket leak

thermostat in backwards.the part that senses temperature change isn't exposed to the hot coolant inside the engine. , or coolent passages clogged, here is what sometimes will happen:



They can and will totally clog up, try to flush the system if not too far clogged.

Hi David, How long did you run the engine before checking the temperature? The thermostat will only begin to open when the engine has warmed and the gauge begins to move. If after giving it a correct warming period it has still remained cold, I suggest the following. As you have already replaced the water pump, thermostat and radiator cap, the radiator may be blocked. Carry out a back flush, meaning, use a good quality radiator flushing chemical and follow the instructions carefully. Run the engine in accordance with the instructions. Let the engine cool and then draining, flushing the system by connecting a hose pipe with a fairly good head of pressure against the usual direction of flow. If that fails you may need to replace the radiator. Let me know how you get on, Happy new year Regards John

Hello! Thermostat should be a 190 degree...you may have an air blockage...Remove radiator cap start engine and leave cap of until all air bubbles are out (even after thermostat opens)...Cap and test for heat...if there isn't any heat...When that thermostat opens and hot water flows through the upper hose of the radiator that hose will be hot and hard..If you feel the heater hose only one will be hot which means that nice hot water is not passing through the heater core...That could be due to blockage or the control in the car isn't opening the valve on the core...check to see if the heat control is opening the valve...If it is, I would suggest that you purchase a back flushing kit ($10) A plastic tee fits into the inlet heater hose and a garden hose is then connected to the tee...Drain the radiator, remove the thermostat, and turn on the water...do this with heat control on high...The system will back flush out of the top of the radiator and hopefully clean the blockage...Reassemble ...Cap off the tee (cap is in kit)...Install thermostat (190) Is a better choice...Refill radiator...Start engine and leave the radiator cap off until all the air bubbles out............At that point you should have heat...Guru...Saailer

I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

mine was same way for a year... tried several things but finally we disconnected hoses under hood and flushed out heater and now works good as new...... hope it helps

Heres a couple of things you can check. Start your car and remove the radiator cap,(before it gets hot mind you) when it reaches norm operating temp, look inside radiator to see if water is circulating. If its not moving, its a bad water pump. Also, youre hoses should never collapse, if they collapse when they get hot maybe you need new hoses? Finally, if those dont work, flush out your radiator. Open the bottom cockpit and use a garden hose and let it flush out the system while the car is running, about 10 mins should do the trick. If the radiator looks clean inside then it doesnt need flushed.

You should never remove the thermostat unless you plan to replace the old one with a new one. Computer controlled cars rely on temperature to adjust fuel mixtures for when the vehicle is warming up and when it reaches operating temperature. You should first inspect for any sign of coolant leaking. Drain the coolant and flush the system by flushing water into the radiator neck with a garden hose for about 10 minutes or more if needed. Then get a new thermostat and drill a small hole in the flat surface ring that surrounds the thermostat and install it and a new gasket on the housing. Replace the radiator cap also. fill the system with coolant and let the engine run with the cap off until it reaches running temperature. Top off the system and install the cap if the car runs at the normal temperature.If at any point you think the car is getting too hot, install the cap THEN shut the engine off and let it sit. You can also monitor the fans to see when or if they are coming on. Turn on the air conditioner but adjust the temperature to hot. One of your cooling fans runs off of engine temperature and the other runs off when the compressor is engaged. If it does not come on with the compressor, the fan relay may be bad. Let me know if you have questions and I can walk you through them if you need me to.

The only reason it won't blow hot air is because the water is not getting to the heater core. Check to see if you have a heater control valve in one of the two lines to the heater core. If so check to be sure that is is opening and closing. If it won't open then you get no water flow in to the heater core.

It dosen't happen often, but the air intake side of the core can become obstructed with leaves etc. If that is the case, the only way I know of to fix it is to remove the core & clean it. You did check the heater control valve to make sure it is allowing proper coolant flow through the core, right? Did you run it after refilling the system with the cap off and the heater on high to purge any air in there?

Yes - Your radiator not only needs to be flushed you could also have an inexpensive procedure done at any reputable radiator shop called "rodding out" and then heat flushed. If I remember correctly 98 Cherokees have a 4.0 in line 6 cylinder motor that has a aluminum radiator. If you remove your radiator yourself (drain detach hoses and unbolt assembly) and bring it to the radiator shop you could get this done really cheap. If you are not comfortable doing this, have them do it for a slightly higher fee. This should really help. NOTE: When adding radiator fluid from now on, use 50/50 premix or if you mix it yourself always use DISTILLED Water. This prevents corrosion buildup in your system. Good Luck!!!