overhauled the system. here are full information of which needed advise and guidelines.

1. Evaporator core looked good. lot of dust and leaves on there. expansion valve is square type. changed the four O-rings. within the valve system only found the high pressure line from firewall to evp core has lots of dirt stick to it. cleaned and find no visible leak in the line. fins looks good. reinstalled.

2. changed all the o rings in the system. couldn't replace compressor relief valve o-ring.

3. when uninstall drier found that lots of white powder in the in and out hole. i bought a new drier but dint install it yet. shall i install and check the pressure with pump? or check pressure leaving the old drier in it?

4. how to add PAG-46 oil in the system. does it require only pouring in anywhere? for example changing drier requires 10mL oil to put. where and how to put?

5. tried vacuum (air type vacuum with small compressor) but couldn't pull enough vacuum. the pulled lines shows good clean inside. no possible clogging. will use a big vacuum.

All the old O-Rings Looked good and not deformed. Although changed all of them. Please advise.

 

3) White powder is likely dessicant from the receiver/drier. This can be a problem for the system as it could block expansion valve and possibly damage compressor. About all you could do now would be to flush lines to firewall disconnect, and remove/inspect/flush compressor. If no evidence of powder, you could avoid removing evaporator again to clean. Evap is difficult to clean in any case as liquids tend to stay inside the evap even w/ pressurisization and pop-release of pressure.

4) PAG oil can be added to compressor, receiver/drier, and lines if necessary. The amount req'd by shop manual is presumably total of all replacement volumes. I've seen specs as little as 4 oz. I've installed as much as 8 oz w/o problems. Better too much than not enough. Every time you check pressures you lose some lubricant.

5) Vacuum as low pressure as possible for at least 30 mins. I usually go to 1-hr. Check that system holds vacuum steady for at least 15 mins after closing gauge set valves.

good luck

 

Thanks for your advise.

Since no A/C solvent is available here, what alternative solvent could i use to flush system?

 

I've used laquer thinner as a solvent to clean AC system. It works well and evaporates quickly when vacuum is applied.

good luck

 

pull the vaccum of the system. couldn't locate leak but big hissing noise coming from low pressure service port where manifold gauge connects. did not replace valve core yet. what it could be? is it valve core or the whole low pressure line?

 

Suggest replacing schrader valve and rechecking. They are notorious for leaking. Sometimes simple removal, cleaning, and reinstallation works.

A hose leak or crimp leak will require replacement of entire hose assy to fix.

good luck

 

Sorry to bother you guys again and again as i am dealing with a piece of hell

Flushed the system and pulled vacuum. High pressure line joint where evaporator connects near the firewall, i put oring and Teflon tape. when i pull vacuum, refrigerant oil comes out from that point. as the oil had UV dye on it, after pulling vacuum it is evident at the joint teflon tape. i take off the put back the connection 3 times but no improvements. the hose end where o-ring goes had a big depth channel for the o-ring but the o-ring i am using doesnt cover the whole area. btw, i dont hear any hissing at that joint during vacuum but after a while i can feel oil at that joint. what to do?

 

The oring seal depends only on a tight gap tolerance between the male and female ends. Teflon tape has no value or function, and might cause problems.

Oring should snugly compress when the male and female parts are joined. It should be prelubed w/ PAG or Nylog oring lube.

Do you have orings sized for that joint? What was source of orings?

When I overhauled my 94EX, I purchased an oring kit from ackits.com that had all the sizes I needed. I had no problems w/ vacuum or pressure seals.

good luck

 

I bought a common oring kit which has different sizes.
Champion O Rings - 3/16-1"ID, Assorted - Supercheap Auto Australia
does the oil come out mean there is a blockage in the system and coming out at the first available way?

 

No it means a leak only. Oil will come out w/ refrigerant at any leak site. There is significant pressure differential pushing to outside at all locations, even low side when system is not operating; roughly equal in psi to ambient air temp.

While you can sometimes match orings; SAE to metric, the original parts are metric sizes. That may be your problem. Slightly too small oring.

good luck