Nissan Repair: 98 Nissan Maxima SE 5spd, electronic climate control, nissan maxima se

Question
Two problems.
Car sounds rough when electronic climate control activates (but not every time).  Difficult to hear when driving at higher speeds.  Notice it when driving in traffic or a drive-thru. When I turn off the system, noise disappears.  When I turn the system back on, sound comes back although not always immediately.  System seems to be working otherwise.

Temperature gauge will shoot up rapidly, after driving for 15-20 minutes during mild weather. This is not a consistent occurence.  When I turn off the climate control, temperature will go back to normal.  This problem is happening with increased frequency.

Thank you.

Answer
W,

The airconditioner will make noise when it gets older.  If it knocks too much you might change the compressor.  but, if it just knocks a little and it does not lug the engine I would let it go until it fails.  The cooling issue could be that the second fan is not coming on with the compressor.  That is, when you turn the air on the second fan is supposed to come on.  If you start the car and turn the air on the other fan behind the radiator is supposed to come on.  If not replace the fan motor.  If both fans are working then replace the radiator cap and flush out the system and change the coolant.  It would be a good idea to change the thermostat too.  And, check to make sure that the radiator is clean  use simple green and spray the front of the radiator down and then flush it clean with a water hose.