5spdfrk

My pressure relief valve recently blew on my compressor and I've replaced it and pulled a vacuum to test that everything works. I'm now going to replace the receiver drier and pull a vacuum once again, but before I do I need to add some PAG oil back to the system. How much should I add and where should I add it...the compressor and the drier?

TIA

5spdfrk

BTW, this is on a 93 civic if it matters as far as oil capacity is concerned.

motegicivic

Typically when you add oil, you pour out the oil from the old compressor and measure it to determine how much oil to add in.

5spdfrk

Since the safety valve released, I'm guessing that all the oil (at least what was in the compressor) was lost at the same time, so figuring out the amount of oil needed is obviously more difficult. I'm open to any suggestions.

motegicivic

Typically a good rule of thumb is about 3 oz, check the AC service label I know on the 96 it is front of the radiator, or maybe under the hood itself. You might be have to check the service manual.

5spdfrk

Ok, I'll look for the label and if I can't find it I'll check the FSM.

BTW, I stopped by autozone to pick up some PAG oil and they have 3 different kinds, PAG 46, 100 & 150. Which one is compatible with Hondas?

5spdfrk

Well from what I've found on HT and elsewhere on the intarwebs, the ND8 & SP-10 oil specified by Honda for it's compressors is the same as PAG 46.

I'll be replacing the drier tonight and pulling another vacuum. Once that's done I'll recharge the system and report back.

angrysmileyface

Are you replacing with R-134a or the R-12 supposed to be in the compressor. 12 requires mineral oil, 134a requires PAG. Also note, the system is supposed to be flushed between switching from 12 to 134a.

5spdfrk

I'm replacing with R-134a, I've already retrofitted the ports/valves with a Honda retrofit kit (38020-SM4-A1AH), however I did not flush the system because it was not part of the instructions. It said that the new oil was compatible with the old stuff.

Hidenplanvew

a 93 shouldnt have r12.. the switch to r134 was in the 80's

angrysmileyface

The switch to R134a occured in the 94 Civic. It wasnt mandated for most cars until 96. And yes, the 1993 I have, still has R-12 in it and blows f'n cold.

5spdfrk

Correct, there are reports of some 93s having R134a, but the vast majority had r12 to begin with.

DSMAddicted

Indeed. Mine is one of the rare '93s with factory R134a.

Hey bud... sorry to hijack, but I changed the valve (closer to exhaust manifold) on my friend's '97 Civic LX yesterday and all the freon escaped (and my fingers froze in the process while I was trying to screw it back in). I reloaded the Freon and the AC works fine (no more leak at the valve), but your thread got me wondering... would Oil have escaped as well? I couldn't tell since my hands got covered with yellow dye. Thoughts?

Thanks in advance.

5spdfrk

My first thought would be that you didn't loose a whole lot, if any, oil since you lost the refrigerant at the charging port valve. Oil is only kept in the reciever/drier, compresser, condenser, and evaporator to my knowledge.

DSMAddicted

Great, thanks for confirming. I'll do more research as well.

5spdfrk

Ok, so I added 4oz to the compressor and 1/3oz to the drier per the FSM. I pulled a vacuum and recharged the system. My low side pressure reading is 25-28 psi and the high side is 160-175 psi. The temp in my garage was around 75 degrees or so.

So my low side pressure is a little low from what I've seen others post, and I'm guessing from what I've read that my expansion valve my be clogged.

I'll drive it around and see how much colder the air gets, but just sitting in the garage it was in the low 50s.

motegicivic

Where do you add the oil?

DSMAddicted

Mine is clogged as well. Up until last year (when it was still "working"), it would blow cold air for 15-20 minutes and then stop blowing and you'd see mist coming from the vents. My understanding is that the clogged expansion valve would freeze and not let R134a flow through. I would turn off AC, keep driving for another 15-20 minutes and turn it on again, and it would work for a few more minutes. Back and forth.

I have a spare evaporator assembly from a '99 Civic that I am putting in mine (adding cabin filter). The expansion valves we have in our cars are typically replaced, but if you want to try cleaning mine when I pull it out (to save time or to take a look before you pull your evaporator assembly), you can have it.

Good luck, keep me posted.

5spdfrk

Oh sorry, I meant to say but I forgot since it was so late and I was tired. I added it directly to the compressor on the low side.

It blew cold the entire time I had the car running after I added the refrigerant which was roughly 30 minutes or so. I'll be driving it a short distance later this evening and then I'm gonna give it the daily commute test tomorrow and see how it does.

I wouldn't mind looking at the evaporator, shoot me a PM with your location.

DSMAddicted

Sounds good... PM sent. Maybe we can get help each other out.