Lacking any appropriate force reference, the device can not effectively estimate superheat, causing inconsistent operation. When exchanging an expansion device, the duty is frequently one of the very labor-intensive and irritating careers in automotive A/C restoration since the device is more often than not hidden serious within the dash, sandwiched involving the evaporator key and the firewall. On several cars, opening the expansion device requires removing the whole HVAC property, meaning draining the cooling system to disconnect heater hoses, removing the steering column, dragging the dashboard, and occasionally even removing leading chairs to produce enough workspace.
Employment which may take one hour on a bench can quickly consume eight to a dozen hours of flat-rate labor time, and that is where in fact the economics of automotive repair become interesting: an upgraded growth device it self may cost between thirty and eighty dollars, nevertheless the job to install it can easily exceed a thousand dollars. That disparity leads several car owners to question whether replacing the valve is worth it, CAR A/C EXPANSION VALVE on an older car. However, the expansion valve isn’t a component that fails arbitrarily; it generally fails as a result of contamination from a used compressor or a program that was remaining ready to accept moisture, leading to internal corrosion.
For this reason, changing an extension device without also replacing the receiver-drier or accumulator, eliminating the whole system, and often replacing the compressor itself is really a recipe for quick repeat failure. The debris that destroyed the original device it’s still moving, and the newest valve’s tiny orifice can block within a few minutes of operation. Furthermore, contemporary expansion valves are increasingly being integrated into “block-type” or “H-valve” assemblies that mix the expansion valve, the evaporator inlet and outlet associations, and sometimes even a pressure switch right into a single, lightweight unit.
These H-valves, called due to their shape resembling the page H, eliminate the requirement for a separate detecting bulb and external equalizer line by incorporating the thermal sensing element directly into the device human anatomy, wherever it senses the heat of the evaporator outlet fuel internally. While that design is smaller sized and less prone to physical damage, additionally, it makes the valve also more difficult to try since there is no additional detecting bulb to check, and it usually involves specific diagnostic procedures. When exchanging an H-valve, the technician should be thorough about applying new O-rings lubricated with the proper refrigerant oil, an average of polyalkylene glycerin for R-134a methods or polyolester for the newer R-1234yf programs, as mixing oils or utilizing the inappropriate form can result in sludge development and catastrophic compressor failure.