The owner of a 2007-12 Altima or 2009-12 Maxima may come into your store with a complaint that the a/c system isn't quite cooling up to snuff. On initial inspection, you might find that the compressor clutch is, indeed, engaging, the system is fully charged, and all the controls and mode doors are operating properly. One possible cause for the trouble, reports Nissan, is a clog in the receiver dryer or condenser.
Start the diagnosis off by connecting your gauge manifold to the low-side and high-side service ports. Now run the engine, activate the a/c system and look at the system pressures. If the low- and high-side pressures are normal or slightly higher than normal, this info doesn't apply. Continue troubleshooting until the problem is found. If the pressures on both the low-side and high-side of the system are lower than normal, touch the receiver dryer outlet tube with your hand (you'll find the tube near the radiator cap). Under normal circumstances, the tube should be warm or hot to the touch. If it is, once again this information doesn't apply; keep searching for the cause of the cooling complaint. If the outlet tube is cool or cold to the touch, that confirms that debris is clogging the receiver dryer or condenser. Don't try to flush the system, it won't work. Replacing the condenser/receiver dryer assembly is the only surefire fix.
"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].