Mini How to do stuff(s) by Neel K. Sanghi

This is a new page as of 4-15-07... this is not yet a complete how to... I'll remove this when it is done...

8-1-07: Added content/edited

A/C Repair

Car A/C systems are actually really simple to repair. In most basic systems you have only a few basic components: compressor, refridgerant, receiver/dryer, accumulator, expansion valve or orfice tube, codenser and evaporator.

You have two accepted refridgerants R12 (vehicles pre 1994 US), and R134a (vehicles 1994 US and later) for automotive A/C's in the US. This isn't to say that just about any compressed gas wouldn't work, because most any would. Some may be more hazardous and less effecient. Perhaps even the molecular size of the substitute gas may be too small to be retained by the walls of the A/C hoses designed for the original refridgerant.

Anyway, you basically check your compressor to see if engages. You do this by starting the car, and turning on the air condition. If you hear a 'click' and the engine idles down as if it is burdened by an additional load then there is a good chance that your a/c compressor clutch engaged (check under the hood to see if its spins) and the compressor is most probably fine. If this doesn't happen then it is most probably for one of these reasons:

• A. Clutch On Compressor is Bad
• B. System is equiped with a low refridgerant switch
• C. Condenser fan/sensor not is malfunctioning

If you hear a squeeling noise when you turn your A/C on its probably because your belt is loose. If your sure your belt is adjusted properly then possibly your car is not using a low pressure switch and your compressor is low on oil which would create additional resistance in the compressor which might cause the belt to slip (squeal).

If the compressor still doesn't come on then you could have a fault in your condenser fan or circuit and there may be no issue of a leaky system at all. This is great for R12 car owners who don't want to do a retro fit to 134a.

If your compressor engaged at all its a good sign (even if it squeeled). Your next step is to find the leak through using UV dye oil/refridgerant. This test may actually make your A/C work again! This involves adding additional refridgerant or oil with UV dye (most common) in it, or some other dye that can be viewed with the naked eye. This dye can be bought by anyone at your local autoparts store. Then start the car and turn the A/C on. Colored refridgerant will ooze out anywhere there is a leak in the A/C and you can then see them with a UV light (ideally) or even with the naked eye (large leak). If the/a leak is in the evaporator core (part located inside your dash that looks a bit like a radiator) than the dye will be invisible.

Okay, so your A/C is working and blowing cold air you added dye/refridgerant to find the system. So why fix the leak now?

• A/C will work more effeciently, consistantly and significantly colder
• Save money on buying refridgerant repeatedly
• Save time in the long run from having to revisit the problem
• Save the environment, and the ozone from chemicals