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New Compressor change questions

OdorCide on Sun June 21, 2009 11:47 PM User is offline

Year: 1994
Make: Volkswagen
Model: Jetta
Engine Size: 2.0
Refrigerant Type: R134A
Ambient Temp: 90
Pressure Low: 48
Pressure High: 220
Country of Origin: Germany

Hello, I'm new to working on A/C systems and I jumped into a project head first. I bought this car with the A/C not working, took it to a shop and they said the compressor wasn't working. I flushed out the lines and condenser with some aerosol flush I bought at the auto parts store, then blew the lines and condenser with compressed air. Nasty gray oil came out. I installed the new compressor and receiver dryer. Did not add any oil because the vendor I bought the parts from said it was filled with all I needed. Pulled a vacuum with my new harbor freight pump, would not hold a vacuum after I removed the pump. Got a leak, grrr. I had to wait a week before I could work on it. So this weekend I tore it apart again, flushed the lines out again. Drained the oil out of the compressor and added 3oz of PAG 46 to the compressor and turned the pulley a couple of times. Installed new o-rings on the TXV, compressor and receiver/dryer. Buttoned it all up and pulled a vacuum for 1 hour, disconnected the pump and to leak after a hour. Fired up the pump and let it pull vacuum for another 30mins. Added 24oz of R134a (2 cans) I stopped at 24oz instead of 28 because of the pressures I'm getting. The TXV valve is new also, forgot to mention that.

While at idle I'm getting 70 degrees out of the vents and on the highway it cools down to about 58 degrees. (Hard to read the little dial). I was worried that the condenser is the problem so I misted it with water tonight and these are the reading I'm getting.

Lo 50psi
Hi 200psi
Vent temps 70

So when I mist the condenser the high side goes down, what does that mean?

When the car is static I get 120psi on the high and low side.

Once the car is up to temp I get

Lo 50
Hi 250
Vent Temp 70

While I was working on this I noticed the fan wasn't going to high speed so I jumped it so it runs high all the time. This was done before all the tests where completed. I have a cheap gauge for the low side and it was reading the same as my good set of gauges so they appear to be working right.

Any help would be appreciated, let me know what I'm doing wrong. Do you think the receiver/dryer is bad because it was open to atmosphere for a week? Thanks in advance.


OdorCide on Sun June 21, 2009 11:49 PM User is offline

I forgot to add that it seems the blend door has lost its sealing foam, it's blowing out of the vents. Can I check the temps on the a/c lines to check and see if that's the problem?

Chick on Mon June 22, 2009 6:45 AM User is offlineView users profile

you need to have the full charge in there, and if you're using can's, you are lower than you think. Make sure the condenser fan(s) are working when the ac is called for, feel the suction line back to the compressor from the evap, should be very cold, if it is, you might have heat from the heater core blending in with the cold air, check these for starters.. Hope this helps..

Email: Chick


Freedoms just another word for nothing left to lose

OdorCide on Mon June 22, 2009 9:28 AM User is offline

Thank you for the response, I will try to add more 134a today. Should I not be worried about the pressure readings I'm seeing? The suction hose in the engine compartment is cool but not cold.

HVargas on Mon June 22, 2009 4:52 PM User is offlineView users profile

Those pressure's are ok. Once you get air moving across the condenser and raise the rpm up to around 1500rpm you will see your low side drop down a little bit. Add the refrigerant little by little. Don't wanna overcharge.


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