Air condtioning and heating system — check and maintenance

Air conditioning system

Warning: The air conditioning system is under high pressure. DO NOT loosen any fit­tings or remove any components until after the system has been discharged. Air con­ditioning refrigerant must be properly dis­charged into an EPA-approved container at a dealership service department or an auto­motive air conditioning repair facility. Always wear eye protection when disconnecting air conditioning system fittings.

Warning: R-1234yf refrigerant is easily con­taminated, and is toxic and flammable. Caution: On R-1234yf systems, the desiccant in the receiver-drier must be replaced if the oil has been contaminated or the air conditioning refrigerant system has been open to atmo­sphere for more than four hours. Damage to the system will result if the desiccant is not replaced.

Caution: All 2014 models covered by this man­ual use environmentally friendly R-134a. 2015 and later models use either R-134a or R-1234yf; these refrigerants are not compatible with each other (nor are their appropriate refrigerant oils) and must never be mixed or the components will be damaged.

Caution: When replacing entire components, additional refrigerant oil should be added equal to the amount that is removed with the component being replaced. Be sure to read the can before adding any oil to the system, to make sure it is compatible with either R-134a or R-1234yf, as applicable.

1. The following maintenance checks should be performed on a regular basis to ensure that the air conditioning continues to operate at peak efficiency.

a) Inspect the condition of the compressor drivebelt. If it is worn or deteriorated, replace it (see Tune-up and routine maintenance).
b) Check the drivebelt tension (see Tune-up and routine maintenance).
c) Inspect the system hoses. Look for cracks, bubbles, hardening and deterio­ration. Inspect the hoses and all fittings for oil bubbles or seepage. If there is any evidence of wear, damage or leakage, replace the hose (s).
d) Inspect the condenser fins for leaves, bugs and any other foreign material that may have embedded itself in the fins. Use a fin comb or compressed air to remove debris from the condenser.
e) Make sure the system has the correct refrigerant charge.
f) If you hear water sloshing around in the dash area or have water dripping on the carpet, check the evaporator housing drain tube (see illustration) and insert a piece of wire into the opening to check for blockage.

3.1 The evaporator drain hose is located on the passenger’s side of the firewall

Chevrolet Silverado Cooling, heating and air conditioning systems _ The evaporator drain hose is located on the passenger's side of the firewall

2. It’s a good idea to operate the system for about ten minutes at least once a month. This is particularly important during the win­ter months because long term non-use can cause hardening, and subsequent failure, of the seals. Note that using the Defrost function operates the compressor.

3. If the air conditioning system is not working properly, proceed to Step 6 and perform the general checks outlined below.

4. Because of the complexity of the air conditioning system and the special equipment necessary to service it, in-depth troubleshoot­ing and repairs beyond checking the refriger­ant charge and the compressor clutch opera­tion are not included in this manual. However, simple checks and component replacement procedures are provided in this chapter. For more complete information on the air condi­tioning system, refer to the Haynes Automo­tive Heating and Air Conditioning Manual.

5. The most common cause of poor cooling is simply a low system refrigerant charge. If a noticeable drop in system cooling ability occurs, one of the following quick checks will help you determine if the refrigerant level is low.

Checking the refrigerant charge

6. Warm the engine up to normal operating temperature.

7. Place the air conditioning temperature selector at the coldest setting and put the blower at the highest setting.

8. After the system reaches operating temperature, feel the larger pipe exiting the evap­orator at the firewall. The outlet pipe should be cold (the tubing that leads back to the compressor). If the evaporator outlet pipe is warm, the system probably needs a charge.

9. Insert a thermometer in the center air distribution duct (see illustration) while oper­ating the air conditioning system at its maxi­mum setting — the temperature of the output air should be 35 to 40 degrees F below the ambi­ent air temperature (down to approximately 40 degrees F). If the ambient (outside) air temper­ature is very high, say 110 degrees F, the duct air temperature may be as high as 60 degrees F, but generally the air conditioning is 35 to 40 degrees F cooler than the ambient air.

3.9 Insert a thermometer in the center vent , turn on the air conditioning system and wait for it to cool down; depending on the humidity, the output air should be 35 to 40 degrees cooler than the ambient air temperature

Chevrolet Silverado Cooling, heating and air conditioning systems _

10. Further inspection or testing of the sys­tem requires special tools and techniques and is beyond the scope of the home mechanic.

Adding refrigerant

Caution: Make sure any refrigerant, refriger­ant oil or replacement component you pur­chase are designated as compatible with the type of system being serviced.

Note: At the time of this manual’s release, R-1234yf refrigerant charging kits were not available for purchase unless you are an EPA certified HVAC technician.

11. Purchase an automotive air conditioning charging kit at an auto parts store (see illustration). A charging kit includes a can of refrig­erant, a tap valve and a short section of hose that can be attached between the tap valve and the system low side service valve.

3.11 R-134a automotive air conditioning charging kit

Chevrolet Silverado Cooling, heating and air conditioning systems _

Caution: Never add more than one can of re­frigerant to the system. If more refrigerant than that is required, the system should be evacu­ated and leak tested.

12. Back off the valve handle on the charg­ing kit and screw the kit onto the refrigerant can, making sure first that the 0-ring or rub­ber seal inside the threaded portion of the kit is in place.

13. Remove the dust cap from the low-side charging port and attach the hose’s quick-connect fitting to the port (see illustration). The fittings on the charging kit are designed to fit only on the low side of the system.

3.13 Air conditioning charging port locations

1 High-side charging port
2 Low-side charging port

Chevrolet Silverado Cooling, heating and air conditioning systems _ Air conditioning charging port locations

Warning: DO NOT hook the charging kit hose to the system high side!

Warning: Wear protective eyewear when dealing with pressurized refrigerant cans.

14. Warm up the engine and turn on the air conditioning. Keep the charging kit hose away from the fan and other moving parts.

Note: The charging process requires the compressor to be running. If the clutch cycles off, you can put the air conditioning switch on High and leave the car doors open to keep the clutch on and compressor working. The compressor can be kept on during the charg­ing by removing the connector from the pres­sure switch and bridging it with a paper clip or jumper wire during the procedure.

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