Front AC blows cold air. Fan works at different speeds just fine. Middle upper vents and rear vents blow very hot air. Measured front vent at 50F and middle/rear vents at 110F I checked thermometer performance, it is accurate. Thought it might be low on refrigerant but at about 85F outside temp, at idle, the low pressure manifold shows 40 psi and high pressure 200 psi. After about 5 minutes at 2000 rpm low pressure is 48 psi and high pressure is 225 psi. AC on full , at lowest setting, the entire time. The four lines that run from the engine along the side of the car passenger side bottom appear to be intact no kinks, splits or crushes all are warm and one is terrifically hot. Any ideas?
Not likely, but Is Hot water flowing to heater coil in back? How hot is "very hot" Is it a refrigerant line? If a refrigirant line, Very Hot means it is hot gas from the compressor that "should be going to the condenser coil usually in front of the radiator. It's almost impossible for that Hot refrigerant gas to go to the cooling coil in the back unless you had some repairs done and they weren't certified. My guess is the radiator hot water is not being controlled properly, due to bad valve or control system components.
Testimonial: "Hi gbob59 - Thanks for your input. Ther are 4 lines running alng the passenger side of the car. With engine on , but NO A/C on, the smaller tube (closest to the car and closest to eh side of the car) is cold. Next to it is a larger tube which is also cold (neither is very very cold, they just feel like cold metal). Below them are two larger diameter tubes, both of which are warm. The tube closest to the interior of the car gets hotter but maybe ~ 110F or so, you can still touch it. With A/C on front only the situation does notchange. When the rear A/C is turned on the small diameter tube gets progressively warmer (but never too hot to handle) and by comparison the tube next to it seems cold. The other tubes, closer to the ground, just stay hot. There has been no A/C work done at all. I recently had front brakes and rotors put on and front struts replaced(at STS) and was going to do rear brakes myself. I also did change number three plug and coil pack last week but the A/C problem pre-dated that. I mention these in case you think something might have been dislodged in the process. What valve or control system for the radiator are you thinking about? FYI car has 66000 miles. Thanks."
I'd guess the larger tubes that are "lower" and 110f are supplying engine coolant to a heater coil in the back Ac housing. But at 110f it's is cooler than normal engine coolant at about 180f to 160. I am guessing the control valve for the rear Heater coil is leaking (not shutting off) a little engine coolant to the rear, in other words just enough to keep it at 110F. I would think this valve is in the engine bay close to the front heater coil piping and controlled by switches or temperature controls on the dashboard. A temporary fix would be to put a manual shut off valve in the hose feeding the rear coil. Probably a rubber hose. Or you may have a better way to shut it off. A heater plumbing diagram should be more definitive. Sometimes Utube has fixes and show how to do it. Or Google images may have the diagram possibly the control valve and what it looks like.
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