Some 2006 Miata models built before Dec. 22, 2005, may experience poor heater performance at idle. According to Mazda, the condition usually surfaces when the car is parked on a downward incline or braked hard before the engine reaches normal operating temperature. An airbound heater core is the likely cause of the heater woes. Installing a new-design water hose, part No. LFG1-15-183B, between the radiator and thermostat housing and bleeding the cooling system should eliminate the heater troubles.
Start the fix by removing the existing water hose between the radiator and thermostat housing. Now install the new hose, making sure the marks on the hose align with the marks at the metal connections. Using a special retaining clip, part No. AJ57-13-243A, secure the new water hose, heater core hose and power steering hose together at the location shown in the illustration above.
Continue the repair by filling the radiator's overflow tank with coolant until the level reaches the Full mark on the side of the tank. Install the radiator cap. Now start the engine and allow it to idle until normal operating temperature is reached. To bleed the system, run the engine at 2,500 rpm for approximately five minutes. Let the engine return to idle, then quickly raise the engine speed to 3,000 rpm for five seconds, followed by five seconds of idling. Repeat this bleeding sequence at least five more times. To complete the fix, shut the engine off and let it cool, then check and adjust the coolant level in the overflow tank.
Some 1999-2002 Frontier Pickups and 2000-02 Xterra SUVs may produce a rumble-type sound from the undercarriage under light acceleration with the transfer case in the 4WD High mode. According to Nissan, the noise is most obvious from 15-35 mph, and is most likely due to the companion flange dust cover amplifying the sound from the transfer case bearing. Installing a new-design companion flange with a special insulating material on the dust cover, part No. 33210-4W100, should eliminate the noise issue. After the new companion flange is positioned, install a new self-locking retaining nut and tighten it to 166-239 foot pounds.
Ford reports that the air conditioning systems on some 2005-06 4.6L Mustangs may blow warm air. If the system has a full charge, no fuses are blown and the compressor clutch won't engage, chances are the clutch has burned up, says Ford. Installing a new clutch assembly and updated orifice tube, and recharging the system to a new refrigerant spec of 26 ounces should restore proper cooling. After you're done with the parts swap, fill out a climate control information decal and place it underhood to alert the next tech that works on the vehicle.
These are the parts you'll need to complete the fix: clutch disc (part No. 6L2Z-19D786-A); clutch coil (4L3Z-19D796-AA); pulley (6L2Z-19D784-A); blue orifice tube (F5XZ-19D990-AB); and an information decal (6R3A-19A286-AA).
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].