Directions: GM Leads the Industry in the Race for a Greener Refrigerant The switch to HFO-1234yf is expected to help GM vehicles meet the overall requirements of the U.S. EPA's latest motor vehicle greenhouse gas regulations. More

Tech Tip: Sealing Pipe Connections on Porsche Expansion Valve Under certain circumstances, refrigerant loss from the area of the expansion valve pipe connections can be misdiagnosed as a defective expansion valve. As of production date October 1993, a longer bolt has been used in the installation of the A/C lines to the expansion valve. The new bolt is installed as a precaution to prevent the expansion valve from distorting, which could cause a leak at the pipe... More

Tech Tip: No or Insufficient Cooling Output in Mercedes-Benz C-Class If an owner of a 2004 C 240 Sedan complains of no or insufficient cooling output, it could be caused by the refrigerant line, whose inner coating has come loose in the flexible section of the hose, causing constriction. More

Tech Tip: Quieting a Ticking or Bubbling Blend Door Noise on Jaguars A Jaguar S-Type owner may complain of a ticking or bubbling noise coming from behind the fascia/instrument panel when using the climate control system. The noise may be the result of one or more of the ­climate control blend door actuators giving incorrect position feedback to the climate control module, causing the blend doors to continually search for their correct position and causing the noise... More

Tech Feature: A/C System Diagnostics Diagnosis is often the biggest challenge, especially if the cause of a no-cooling problem is not obvious. Is it the refrigeration circuit, an electrical problem or a control issue? More

Directions: The Impact of HF0-1234yf on Service Shops According to the new refrigerant's developers, there are chemical differences between HFO-1234yf and the current R-134a system. As a shop owner, you'll need to learn the Safety, Equipment and Charging Issues surrounding this new refrigerant. More

Tech Feature: New Refrigerant Change May Not Be a 'SNAP' The introduction of HFO-1234yf in vehicle A/C systems in the U.S. could be a few years away. However, it is plausible that some (dealership technicians and collision repairers) may see HFO-1234yf systems by late 2011 and early 2012, as European models begin the R-134a phase-out and make their way across the pond. (R-134a is to be completely phased out of new European systems by 2017.) More

Lexus Tech Tip: A/C Condenser Fan Relay Corrosion on 1998-2000 LX 470s Some 1998-2000 model year LX 470 vehicles may have a condition in which the A/C condenser fan continues to run after the ignition is turned off due to corrosion in the relay connector. A repair kit (P/N 88840-60070) consisting of a new relay and sealant has been made available to correct this concern. More

Toyota: Insufficient Cabin Cooling Some 2001-’04 Sequoia and 2000-’04 Tundra vehicles may exhibit a condition where the air conditioning system does not sufficiently cool the cabin. Adjustment of the water control valve is necessary to correct the condition. Repair Procedure: 1. Turn the temperature control knob to the full cold position. More

Tech Tip: Kia A/C Compressor Bracket Replacement Some 2002-'05 Sedona (GQ) vehicles may exhibit a humming noise and vibration when the A/C is turned on. To address this condition, replace the A/C compressor bracket with P/N 1K52Y 15810FFF. More