QUOTE(marumaru @ Jul 26 2012, 10:10 AM)
Things to check for old car a/c system and goto car aircond shop, not workshop.
1. AC Gas - If low, top up. Usually can last up to 2 years. If 3 months lose gas already, ask them to check if got leakage at pipes or joints. they have gas detector to do that if u go to proper car AC shop. Gas can also leak through the gasket of older compressor.
2. Low gas cutoff sensor for compressor - Some idiot usually advise to bypass this sensor when it's faulty. What will happen is when your gas is low the compressor will keep on running spoiling the compressor. Happens to my old car last time, change compressor 3 times because of this.
3. Thermostat - rarely spoilt, but if spoilt will cause your condenser to over cool and makes water in the condenser freeze to ice. Air flow will be blocked and no air will come out of your blower until it melt again.
4. Compressor - The heart of the AC, if older than 3-5 years usually have issue like gasket leaking or wear and tear on the piston. Will die really fast if the low gas cutoff switch have been bypassed.
5. Condenser - Place where the air become cool and hot air is absorbed. Rarely need any attention because a normal cleaning shoul dbe sufficient if it's too dirty. Only need to change when there's leaking but only on really2 old car.
Always try 2-3 different shop to troubleshoot before you repair, checking is always free and it's good to have a 2nd opinion especially if you're not familiar with the shops. Ask the problems and price for repairing it. Compare it with other place.
There are oil stain left on the place it leaks.. Depends on what type of compressor, sometimes it will leak at shaft shield.
Condenserr and Evaporator
Condenser to reduce/discharge the heat of the compressed liquid
Evap= To absorb surrounding air/heat. Changed liquid to Wap/Moist
yu need to add oil in the compressor so it will not spoil/Jem
lowgas sensor & thermostat is the same thing.. If spoil it will make yr Valve frost and yr liquid stuck in it, will make yr compressor keep compress it and damage yr piston.
Check the gas pressure is free.others yu have to pay. Evaporator normal got 1 year warrant. compressor -3month. Liquid filter also need to change.