MK378 has you covered. Reread post #2.

Does the compressor clutch engage?

Have you measured the refrigerant pressures on the low and high sides?

 

The pipeline from the firewall is cold when the air is working, when the air starts to blow warm ,i checked the pipes and they were warm also.

Where is the compressor located? i tried to follow the Low pressure line but could not find it.

Thanks

 

Measure the refrigerant pressures on the low and high sides. Either take it to a shop or obtain a manifold gauge set. The pressures can be used to diagnose the problem.

 

The compressor is on the bottom front of the engine on the driver's side (the unit near the top on the front of the engine is the power steering pump). The compressor has a belt that goes over a small pulley then down to a larger pulley on the compressor itself. Beside that pulley, almost touching it, is the clutch plate. When the compressor is engaged the clutch plate does touch the pulley and will spin along with the engine, when it is not it will be sitting still. Start the engine, stay way away from moving parts, and have someone push the A/C button on and off a few times while you watch to see how it works. Then wait until it stops cooling and look, it probably will not be engaged.

For now I think the refrigeration is OK because it gets cold for a while. If the compressor is still turning but the pipes and air are warm, you have a refrigeration system problem that will require measuring pressures. Much more common is a clutch gap or electrical problem causing the compressor to stop.

 

I think you are right mk. I re-looked at the A/C circuit diagram and found that if high or low refrigerant pressure were tripping the pressure switch, then both the condenser fan and compressor clutch would turn off.

 

IF the clutch is not spinning What has to be done ? service wise to the clutch?

What are the pressure specs for Low and high side

 

As mk has mentioned, check the clutch gap. It may be too wide or the clutch coil is going bad. I guess a bad thermoprotector could also be the cause or the compressor is overheating.

I believe I was off track by my earlier recommendation that you look at the refrigerant pressures as, if this were a problem, both the condenser fan and the compressor would stop running when the A/C starting blowing warm air.

 

I hope it wasn't wrong to jump in the middle the other day with my a/c trouble also. But I did fix my intermittent a/c with a replacement clutch and coil. Ran it all the way home from work (110 miles, yes 110) and it cycled normal and never just quit. You guys really go the extra with the diagrams and all. Pleasure, thanks.

 

I have some similiar problems with my 98 that I am looking for some help on. It blows cold sometimes then gets warm. I replace the compressor dryer and the evaporator valve and vacumned the system for over an hour. Serviced the system and it worked ok for the first 1000 miles although it never really blew ice cold air. Then it started blowing warm air all the time. The condensor fan runs but the high side pressure runs up to about 450 and the low side is around 200 or so. when you turn off the system the pressures don't equalize at all and the pressure on the high side drops until you turn the system back on. Thought from an earlier post that it may be over serviced or have air in system. Bled some air off and now the system does not get cold or cool at all. I am suspecting that maybe the condensor fan does not run all the time like it is supposed too. Am considering taking to shop for system drain and flush and reserviced with 21 to 22 ounces like it says on the sticker under the hood, but if could get some pointers or help that could save me the cash that would be great.

 

The low and high side pressures are way too high: