ACtion Magazine - June 2012 - (Page 35)

Battery is Dead, or A/C Cools Poorly 2007-2011 Acura MDX ou may encounter a 2007-2011 Acura MDX that experiences battery failure and/ or the A/C cools poorly. These symptoms may occur after the vehicle is parked for a short time or overnight. Also, the A/C compressor may be noisy and may be emitting refrigerant vapor from the relief valve. The probable cause is the A/C compressor clutch relay may be sticking closed. If the relay sticks when the ignition switch is turned to LOCKED with the compressor running, it can create enough parasitic draw to discharge the battery. If the relay sticks while the engine and compressor and the A/C are running at a low vehicle speed, the A/C pressure may spike, causing the compressor’s relief valve to open and lose refrigerant. The corrective action is to replace the A/C compressor clutch relay and the relief valve, if needed. First, however, diagnose the battery condition and recharge or replace it as needed before moving on to the A/C components. Diagnosing A/C Problems Start the engine and let it idle until the cooling fans come on, then turn on the A/C, making sure the LO, AUTO and RECIRCULATION modes are selected. Hold the engine at 2,000 rpm with the doors and windows closed and observe the A/C compressor clutch. NOTE: The clutch and cooling fans should always cycle Y together. The clutch should never be engaged when the cooling fans are off. Check the relief valve area for traces of refrigerant oil. If you find oil, the valve has opened to relieve excess pressure. Refrigerant vapor may also be present if the valve opened. Repair Procedure Install a new A/C compressor clutch relay (P/N 39794-SDA-A05) in the underhood fuse/relay box. If you find traces of refrigerant or PAG oil around the compressor relief valve, recover the refrigerant from the system and replace the relief valve using the specific information for the vehicle you are servicing. Remove the relief valve and o-ring. Plug the opening to keep foreign matter from entering the system and the compressor oil from running out. Do not reuse the o-ring. Clean the mating surfaces and apply a thin coat of refrigerant oil to the new o-ring and install it on the replacement relief valve (P/N 38801-P9K-E01). Remove the plug and install the new relief valve and tighten to 13.2 N•m (9.7 lb-ft). Recharge the system with the correct levels of oil and refrigerant according to the specific service information. Acura says 1 oz. of oil should be added to replace any lost when the relief valve opened. Check for leaks and proper operation before returning the vehicle to the customer. ❆ ACTION • June 2012 35

Table of Contents for the Digital Edition of ACtion Magazine - June 2012

ACtion Magazine - June 2012
Contents
Outlook
Expansive Valve
Technically RELAY-ted
Under the Southern Cross
Leonard's Law
Cooling Corner
Virtual View
News & Updates
State of the Art Detection
Running Short On Time and Info
The End of R-134A?
Association News
Quick Check
New Products & Services
Last Watch

ACtion Magazine - June 2012