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Re: Rear heater core is hot in and out the condersor is...
It is pluged. That is why you have cold air blowing. If it is possible take the heart core out and drain all the anti frezze out you can. Fluch it out with water as much as possible. Put some water into one side of it and see if it comes out the other. If not add about a half cup of draino in it and let it set for about 10 min. If water runs threw it ya got it if not add some more untill you get the water to flow through it freely. Reinstall and you should be fine.
sounds like the air-conditioning expansion valve is probably not working correctly here is a way you can fix your air conditioning:
Realize that auto AC is basically a refrigerator in a weird layout. It's designed to move heat from one place (the inside of your car) to some other place (the outdoors). While a complete discussion of every specific model and component is well outside the scope of this article, this should give you a start on figuring out what the problem might be and either fixing it yourself or talking intelligently to someone you can pay to fix it.
Become familiar with the major components to auto air conditioning:
the compressor, which compresses and circulates the refrigerant in the system
the refrigerant, (on modern cars, usually a substance called R-134a older cars have r-12 freon which is becoming increasingly more expensive and hard to find, and also requires a license to handle) which carries the heat
the condenser, which changes the phase of the refrigerant and expels heat removed from the car
the expansion valve (or orifice tube in some vehicles), which is somewhat of a nozzle and functions to similtaneously drop the pressure of the refrigerant liquid, meter its flow, and atomize it
the evaporator, which transfers heat to the refrigerant from the air blown across it, cooling your car
the receiver/dryer, which functions as a filter for the refrigerant/oil, removing moisture and other contaminants
Understand the air conditioning process: The compressor puts the refrigerant under pressure and sends it to the condensing coils. In your car, these coils are generally in front of the radiator. Compressing a gas makes it quite hot. In the condenser, this added heat and the heat the refrigerant picked up in the evaporator is expelled to the air flowing across it from outside the car. When the refrigerant is cooled to its saturation temperature, it will change phase from a gas back into a liquid (this gives off a bundle of heat known as the "latent heat of vaporization"). The liquid then passes through the expansion valve to the evaporator, the coils inside of your car, where it loses pressure that was added to it in the compressor. This causes some of the liquid to change to a low-pressure gas as it cools the remaining liquid. This two-phase mixture enters the evaporator, and the liquid portion of the refrigerant absorbs the heat from the air across the coil and evaporates. Your car's blower circulates air across the cold evaporator and into the interior. The refrigerant goes back through the cycle again and again.
Check to see if all the R-134a leaks out (meaning there's nothing in the loop to carry away heat). Leaks are easy to spot but not easy to fix without pulling things apart. Most auto-supply stores carry a fluorescent dye that can be added to the system to check for leaks, and it will have instructions for use on the can. If there's a bad enough leak, the system will have no pressure in it at all. Find one of the valve-stem-looking things and CAREFULLY (eye protection recommended) poke a pen in there to try to valve off pressure, and if there IS none, that's the problem.
Make sure the compressor is turning. Start the car, turn on the AC and look under the hood. The AC compressor is generally a pumplike thing off to one side with large rubber and steel hoses going to it. It will not have a filler cap on it, but will often have one or two things that look like the valve stems on a bike tire. The pulley on the front of the compressor exists as an outer pulley and an inner hub which turns when an electric clutch is engaged. If the AC is on and the blower is on, but the center of the pulley is not turning, then the compressor's clutch is not engaging. This could be a bad fuse, a wiring problem, a broken AC switch in your dash, or the system could be low on refrigerant (most systems have a low-pressure safety cutout that will disable the compressor if there isn't enough refrigerant in the system).
Look for other things that can go wrong: bad switches, bad fuses, broken wires, broken fan belt (preventing the pump from turning), or seal failure inside the compressor.
Feel for any cooling at all. If the system cools, but not much, it could just be low pressure, and you can top up the refrigerant. Most auto-supply stores will have a kit to refill a system, and it will come with instructions. Do not overfill! Adding more than the recommended amount of refrigerant will NOT improve performance but actually will decrease performance. In fact, the more expensive automated equipment found at nicer shops actually monitors cooling performance real-time as it adds refrigerant, and when the performance begins to decrease it removes refrigerant until the performance peaks again.
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There should be a actuator valve on the line that determines if the heater core gets hot water or cold water. When the heater is selected, the actuator opens and lets hot water into the heater core. It sounds like that actuator is corroded and not opening.
Possibly the heater core is 90% blocked. open enough to draw hot water in, (hose feels hot) but not enough volume to provide heat from very cold air, 10% hot water gets cold quick, coming from core..
Flush heater core in reverse direction - cold side in hot side out..
Sound like maybe your a/c condensor fan is not working, should come on with a/c on, the fan sit in front or back of radiator, condensor is bolted to the front of the radiator, if its not working at stops no air blows through condensor and pressure will get high and a/c wont blow cold, while driving air is running through condersor so a/c will work fine.
Hello.Maybe I can steer you in the right direction. There is an actuator temp,door motor.It may be hard to find,but most of them are on the bottom of the blower box about where the ac hoses and the heater core is,under dash.This motor has gone out,it switches from cold to hot ,and all in between .Hope this is helpful.If not let me email@example.com
If there is no sign of coolant loss (air pocket in heater core),then check for plugged heater core. Both hoses should be very close to same temp with engine at operating temperature with heater fan on high setting.If the return hose is alot colder, then coolant flow is restricted.
locate the rear heater hoses, make sure eng is at operating temp.
fill of the 2 hoses , should be worm tot he touch, if one is hot and the other is luke warm, the problem is in the circulation in the rear heater core. thanks and good luck . let me know. kindest regards Bill ps. don't over look the fan speed at the rear core.
Notorious for plugged heater cores. Also updated plastic restrictioncouplers mounted at heater core available from dealer. Try back flushing heater core. Run engine till its at operating temperature then carefully hold the inlet and outlet hose breifly with heater fan on high if hoses are nearly the same temp then flow is good , if not then core is plugged.
first, make shure that the water level in the radiator is apropriate, then ck the thermostat for oppening and closing(you wont have a heater if the thermostat is constantely open) ck the 2hoses that suply hot water to the heater core, both hoses must be hot when engine is runing .if one off the hose is cold ,the hot water is not circulating to the core and back to engine .ck the valve , see if you can by pass it and see the results if you have heater , replace the valve. nicolas