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Compressor Replacement Procedure Help Needed

s5+5 on Wed June 11, 2008 4:50 PM User is offline

Year: 1994
Make: Chevrolet
Model: S-10
Engine Size: 2.2 I4
Refrigerant Type: R134
Ambient Temp: N/A
Pressure Low: N/A
Pressure High: N/A
Country of Origin: United States

Hi all, newbie here just joined the site, full of great info!

I have a 1994 S-10 that I'm going to attempt to replace the compressor, dryer and orifice tube on this weekend (assuming everything comes in in time) and was hoping to get some good advice from some of the users on the following:

Tips and tricks on replacing the compressor, anything I need to be aware of.

Special tools I might need when replacing the dryer or orifice tube - dryer appears to be standard but I'm unsure about the orifice tube.

Recommended procedure for putting the new PAG oil in, vacuum, re-charging - should I even attempt this or take it to a shop and have them do it once I reinstall all the new parts/pieces.

I'm pretty mechanically inclined, built a couple vehicles but haven't messed with A/C before and would like to know anything up front before I get too deep into this.

Thanks in advance for all your help.

Jason


Edited: Wed June 11, 2008 at 4:51 PM by s5+5

Chick on Wed June 11, 2008 6:55 PM User is offlineView users profile

Your's is pretty straight forward, There is a "hint' on those R4 compressors though. When trying to remove the bolts, you'll see one edge is flat to allow the bolt to come out of the bracket. May need to rock it a bit also. The O tube is in the line that goes down past the accumulator to the lower line in the evap. A needle nose pliers will pull it right out..Add the oil in the different parts. Make sure a couple ounces in the compressor, most in the accumulator. You don't want it to start dry, but once it does, it will be thru the system in no time...
Vac./charge procedure

If your S10 is already R134a, charge by weight, not pressures..Hope this helps.

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

GM Tech on Wed June 11, 2008 11:33 PM User is offline

Good luck breaking the evap to A/D connection loose-- Galvanic corrosion is noy your friend-- I typically don't replace the A/D idf this connection is not able to be broken loose-- I have read many post where folks destroy the threads and then need to replace the evaporator- also the OT connection can be a bear....

Why are you replaceing the compressor? for a leak or for noise or for function? I don't even check the OT or change the A/D for compressor leaks

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

s5+5 on Thu June 12, 2008 11:23 AM User is offline

Quote
Originally posted by: Chick
Your's is pretty straight forward, There is a "hint' on those R4 compressors though. When trying to remove the bolts, you'll see one edge is flat to allow the bolt to come out of the bracket. May need to rock it a bit also. The O tube is in the line that goes down past the accumulator to the lower line in the evap. A needle nose pliers will pull it right out..Add the oil in the different parts. Make sure a couple ounces in the compressor, most in the accumulator. You don't want it to start dry, but once it does, it will be thru the system in no time...

Vac./charge procedure



If your S10 is already R134a, charge by weight, not pressures..Hope this helps.

Thanks for the info Chick, very helpful. Yes it is already R134a.

Are there obvious locations to add oil to the compressor?

What's your take on once I get everything installed to take it to a shop and have them vac it and charge it? I may not have access to a vac system and want to make sure it's done right.

Thanks!

Edited: Thu June 12, 2008 at 11:28 AM by s5+5

s5+5 on Thu June 12, 2008 11:33 AM User is offline

Quote
Originally posted by: GM Tech
Good luck breaking the evap to A/D connection loose-- Galvanic corrosion is noy your friend-- I typically don't replace the A/D idf this connection is not able to be broken loose-- I have read many post where folks destroy the threads and then need to replace the evaporator- also the OT connection can be a bear....



Why are you replaceing the compressor? for a leak or for noise or for function? I don't even check the OT or change the A/D for compressor leaks

Understandable on the galvanic corrosion, I'll take the risk and if it cannot be broke loose then I'll deal with that too. Do people typically destroy the threads on the hose portion? i.e. the female threads, or the male threads on top of the A/D? I figure the stuff is 14 yrs old so I'd like to put a new A/D in if I can.

To address your question on the compressor - yes it leaks, on a scale of 1-10... 9. Most likely the front seal - the tech showed me what it was doing, blowing everything right out the front all over the place, very nice mess.

I've got a new compressor coming, A/D and orifice tube and the PAG oil needed for the system.

mk378 on Thu June 12, 2008 11:44 AM User is offline

I agree with GM Tech, since it's a leaky compressor, punt on the A/D if the fittings won't come loose. Replace the compressor and leave the rest alone.

Pour oil into the inlet of the compressor or into one of the lines, it will find it's way. It is factory R-134a not a conversion, right? On conversions you may be using ester oil instead of PAG.

GM Tech on Thu June 12, 2008 12:35 PM User is offline

They typically destroy the threads on the evaporator-- which means the new A/D won't thread onto the old evap--- or will try to cross-thread- real risky if you can't snap it loose- forget it-- don't force it loose or you will forever kick yourself......

Jobs like yours are my "money makers" - I would meerly change the shaft seal right on the truck- just pull the top radiator shroud off- to access the front of the compressor-- have done them in 45 minutes- start to finish-- but I have all th etools in a special shaft seal tool box that I carry right to the vehicle- like a surgeon....but the end result is the same- your method or my method- we both have cold air......

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Thu June 12, 2008 at 12:37 PM by GM Tech

s5+5 on Thu June 12, 2008 10:35 PM User is offline

MK378 - Alright, will take a look at the A/D fittings and assess the situation when I get in there. Good info on the oiling too, thanks!
BTW, the system is R134a from the factory, not a retro.

GM Tech - In my situation... the A/D is not located near the evaporator, it's tucked up close to the compressor with an inlet and output line (female) on it. The lines then run back to the evaporator. I'm sure you're familiar with this situation. That's why your mentioning the "destroying the threads on the evaporator" sort of throws me for a loop as I won't be touching the evaporator. Were you merely suggesting at the evaporator side is where the threads get galled up, or am I not following you?

Also - what was your take on the O-tube, leave it be, i.e. attached to the evaporator? Thus replacing just the dryer and the compressor.

I considered doing the seal swap, but for your very reason of "I have all the tools" is the reason I'm not replacing the seal. I don't have any special A/C tools so that's why I post on here for your suggestions. Very helpful, I appreciate it.

GM Tech, what's your thoughts on having a shop evac it and charge it for me once I'm done, not sure I'll have access to an evac.

Thanks!

Edited: Thu June 12, 2008 at 10:38 PM by s5+5

GM Tech on Fri June 13, 2008 8:38 AM User is offline

Sorry I missed your engine size as a 4 cylinder- you have a V-5 compressor- not the R-4 on the 6 cylinder S-10s-- most S-10's are 6 cylinder/R-4 compressors, that I see-- the same thing applies- they used the same shaft seal- the A/D change and threads should not be an issue- the OT check is good to do- but not mandatory for your failure mode of a leak.

Sure a shop can evac and fill your system- but they will probably never take responsibility if there are problems- like what amount and who is to add the oil type questions...

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

s5+5 on Fri June 13, 2008 1:59 PM User is offline

Excellent info, thank you. I just got my parts and they look good - I'll keep you posted as to how it went...

As for the shop, eh' I'll deal with that as it comes.

Thanks again for all your help!

JD

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