Auto Service Professional

APR 2018

Magazine for the auto service professional

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36 | ASP April 2018 Technical compressor clutch slipping. In some cases you may be forced to remove the grille in order to gain cleaning access. A gap between the radia- tor and condenser can easily trap road debris. 2. Inspect for system service caps, which should be tethered. Make sure that the correct caps are in place. Improperly fitting caps will not seal properly. 3. Verify that the shroud is not missing, as well as inspect for missing airflow seals. is is especially important if the vehicle has been involved in a collision. ere's always a chance that a body shop may have overlooked this. 4. If a clutch fan is featured (as opposed to electric fans), check clutch condition. With the engine cold and off, the fan should spin by hand no more than 5 times. If the fan spin is stubborn, and/or stops within a single turn, the clutch is partially locked up, which will affect engine warm-up. If the fan spins very easily for about 5 turns with very little resistance, the clutch may be worn or leaking. 5. Inspect electric cooling fan operation (even if a clutch fan is present, the vehicle might also be equipped with an electric fan). Test the blend-air or temperature door opera- tion. Make sure the heater coolant valve and outside air flap door are closed in Max A/C. 6. Check engine idle speed stability. If the engine hot idle remains rough (contaminated throttle body, deposits from crankcase ven- tilation, etc.) the powertrain computer often shuts down the A/C if engine idle is rough. 7. With the engine idling, turn on the A/C and see if the clutch engages smartly. If it doesn't, check the voltage to the clutch. If it's marginal (for example, at or under 11 volts), the clutch may slip in extremely hot weather. Look for a loose or corroded connection at connectors. 8. Do an A/C performance test. e correct procedures vary, so check the service manual. With pressure gauges connected, the system should be in "recirc" regardless of vehicle make/model. (Preventive maintenance tips courtesy the Mobile Air Conditioning Society [MACS].) Quick system check increases A/C work With the average age of vehicles on the road today at around 11.5 years, there is an enormous opportunity for A/C charging and related services. When a vehicle enters the shop for work not specifically targeted for A/C work, the system is not likely to be inspected unless the customer has complained about HVAC issues. As a result, the technician may not be prompted to check the system, not seeing the need to roll the diagnostic/ recovery/charging equipment to the vehicle. However, a quick check for leaks and system pressures can be handled using a simple test kit in conjunction with a smart phone (or tablet). An example is Yellow Jacket's ManTooth wireless pressure/temperature gauge kit, which allows a quick connection to high and low pressure sides without the need to use a manifold or machine. Gauges are included for both R-134a and R-1234yf systems. Wireless signals are transmitted to a technician's smartphone via Bluetooth, pro- viding a fast check of current pressures and temperatures. e check takes only about 3 minutes of additional time as part of standard checks such as tire pressure, fluid levels, etc. If a leakage/pressure/temperature issue is evident, the customer can then be informed, recommending a system repair or simple recharge. It's a quick and easy way to up-sell Several manufacturers offer machines for hybrid and non-hybrid applications. An example shown here is Robinair's 34788NI-H, designed for R134a refrigerant recovery, recycling and recharging. Features include automated refrigerant refill and oil drain, and program to recover, vacuum, leak test and charge. Visual and audible alerts notify the user when service is complete or if a problem has occurred. The machine has the ability to add a printer, USB data sharing, refrigerant identifier and a wireless module for Bluetooth communication. Photo courtesy of Robinair

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