Questionwell it is a 99 sorry and the engine is a 3.5l and i really can't give anymore details because the heat work a couple days ago but it don't now and temp gauge just stop regestering about the same time
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I have a Chrysler lhs which temp gauge is out also the heat only blows cold air and the a/c no longer works temp won't go below 74
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Hi Joseph,
You didn't tell me the year or the engine so I have to give less specific answers. Until you get the temp gauge to work again it will be difficult to diagnose the heater problem and perhaps the AC issue. It could be that your thermostat is stuck open so the coolant is not heating up as it should to provide heat in the car. The temp sender is located adjacent to the hemispherical manifold on the top of the engine where the top radiator hose is attached. (The thermostat is inside that manifold, by the way). The sender has a single tan/black wire. Try disconnecting that wire from the sender and alternately ground the wire and let it float freely and see if the temp gauge reads at alternate ends of the scale; of course the ignition key should be in the 'run' position while doing this observation. If so, then there is something wrong with the temp gauge sending unit and it should be replaced. If not, the either the wire is disconnected somewhere along the path to the engine control module located near the battery, of the gauge is broken. You can check for continuity of the wire from the sender to engine control module at pin 2 of the 60-way plug to the controller using an ohmmeter. If it is continuous, then the problem is with the gauge unit itself.
Have you felt the water hoses that flow through the firewall from the engine compartment to the heater core to see if they are equally hot? If one is hot and the other noticeably cooler then probably the heater core is plugged so that heated coolant is not going thru it, and that would explain why you have no heat. You can reverse flush the core to try and get it flowing again using a garden hose.
The A/C could be a failed compressor or the refrigerant level in the system is less than necessary to produce compressed refrigerant to operate the system. An AC/radiator shop can tell you what is the problem with that.
So let me know what you learn by trying some of these suggestions and we can go from there. Please tell me the year and the engine.
Roland
AnswerHi Joseph,
I suspect that if you are in a cold climate that your engine's thermostat is stuck open so that the coolant is flowing freely through the system so well that it can't warm up the engine or the heater core properly. See if the water hoses feel hot, and also check whether the smaller heater hoses that go from the engine side to and through the firewall are hot, and approximately equally so. If all these hose seem only moderately warm after driving the car for a few miles then that is the reason for the lack of heat and for the gauge not moving up from cold. The hoses should be near the temperature of boiling water.
The thermostat is in that housing I described, on the top of the engine. You will want to open the radiator drain and drop out about a quart or so of coolant into a pan for reuse. Then loosen the bolts on the hemispherical housing that is attached to the top radiator hose and remove them. The thermostat is underneath the housing. You will want to have bought a new thermostat and gasket for the sealing surface between the housing and the engine. Notice how the old thermostat is positioned, then remove it and put in the new one. Then clean the mating surfaces to remove the old gasket and crud. Then dip the new gasket is water and apply it. Then put the housing back in place and retighten the bolts being careful not to break them by too much tightening, but still tight enough to prevent a leak. If you have access to a torque wrench the bolts should be tightened to 20 foot-pounds of torque which is about the same a when you install a spark plug. Then put the drained coolant back in the radiator or overflow bottle. After driving the car for a while check for leaks around the housing.
Let me know if the engine hoses and radiator hoses instead of cold in fact are hot, for my consideration of another explanation than that it is a stuck open thermostat. There is no way to check for a stuck open thermostat other than to open the housing and remove it for visual inspection though the failure to warm up is a sign of such a problem.
Roland
