Question about 1988 Jeep Wrangler

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Not enough heat coming out of the heater of 1988 2.5L Jeep Wrangl

I already changed the coolant and put 195degree thermostat. The heater outlet hose from the engine to the heater core gets hot - after 5 minutes
running. The heater produces not too hot out of the dash board or out to the floor. Found also, the larger hose from the heater core toward back or return heater hose to the engine was more colder. Does it mean I have a problem with heater control valve or I have a partial clogged heater core ? And if I have a partial clogged heater core,.. is it possible I can reverse the flow of coolant to release the clog inside the heater core? Thank you very much for what ever opinion or helping information to me. Oscar

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It sounds to me your heater core is plugged. you can try to back flush it,being this vehicle is twenty yaers old,i would say to replace it

Posted on Dec 15, 2008


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1995 jeep wrangler yj low heat after changing heater core -would reversed heater hoses cause this also- thank u -so much

Not really, the heater core would still get hot enough to produce enough heat and usually the hoses will fall to the right spot making it hard to put them on the wrong ends. Why was the heater core changed? was it clogged? Did you flush the engine out to prevent the new core from clogging up? Have you looked into it being a stuck open thermostat?

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My 2004 Jeep Liberty has started losing heat although the temperature gauge has remained normal. Would this most likely be because of the thermostat or something beyond that?

You may be right, but, here are a few things that come to mind.
1. If your coolant level is low, it could cause this, I would check that first, if you haven't already.
2. If you let the vehicle idle for 6 to 8 minutes and then turn the heat temperature and fan on high, you should hear a click when the thermostat opens to circulate the coolant through the heater core. If you do not hear a click, it could be your thermostat.
3. Turn the engine off and, very carefully reach back behing the engine at the fire wall. You should see 2 small hoses, about 1 inch in diameter, feel both of them and see if they're both hot. If they are, your thermostat should be fine, if only 1 of them is hot than you do have a bad thermostat, or your cooling system has some blockage and the system should be flushed.

I hope this helps.

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You may either have a bad thermostat or a bad fan relay. If the fan is not turning on at all then the relay is bad. If there is not any heat coming through the heater then your heater core is plugged. That would also cause an overheating problem as well. To rule out a bad relay check to see if you are getting 12 volts at the fan connection. If not change relay.

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