Author Topic: Air Conditioner Repair - Gen 2.5  (Read 2132 times)


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Air Conditioner Repair - Gen 2.5
« on: April 06, 2018, 10:28:14 AM »
I do have the paper FSM - but I'm not super experienced with air conditioners yet..   and I can't seem to find the orifice unit on the diagrams but I think it may be blocked.

Here's the current status:

  • Air is not cold from vents.    It does not feel even slightly cool.
  • I have not checked system pressure yet (just received gauge set from Amazon.. ) but the compressor does engage when air conditioner is selected and fan is on
  • Front condenser aux fan turns on
  • None of the HVAC tubes under the hood feel hotter or colder than anything else under the hood

The compressor would not engage if there was no pressure right?      And,  if there is pressure in the system that means there is refrigerant - so if there is refrigerant and the compressor is running, the only thing that could really keep it from being cool is if the orifice tube is obstructed.    Am I on the right track?   

Thanks for any constructive advice (other than "take it to a shop!" - I'm trying to learn something here!   :)  )

I found where the orifice is, unfortunately it's inside the dash... guess I'll be worrying about that later when I have time for a dash disassembly


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Re: Air Conditioner Repair - Gen 2.5
« Reply #1 on: April 06, 2018, 10:33:21 AM »
I can't remember for sure...but I think you're right.
Without pressure, a compressor won't engage.


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Re: Air Conditioner Repair - Gen 2.5
« Reply #2 on: May 05, 2018, 01:50:49 PM »
I had the same thing. Hooked my gauges up (I do residential AC) and sure enough the low side was at 0 with pressure on the high side being too high. Replaced my thermal expansion valve(was sticking shut) and also the filter dryer and AC blows nice and cold now. Really is easy to get the evaporator out. Just took the glove box out.


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Re: Air Conditioner Repair - Gen 2.5
« Reply #3 on: May 10, 2018, 11:53:16 AM »
You can check the electrical side and make sure the Compressor clutch is being triggered.
Keep your cars analog.
1990 Talon TSi
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1999 Montero "Cold weather"


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Re: Air Conditioner Repair - Gen 2.5
« Reply #4 on: May 10, 2018, 12:26:06 PM »
I probably should update this thread -

I hooked up HVAC gauges and saw that static (system off) pressure was around 35psi.   

So had the remaining refrigerant recovered,  then vamped it at home and let it sit with valves closed for a few hours,  pressure didn't rise at all - stayed at the minimum level on the gauge.   Replaced the drier (because it's cheap and easily accessible) and poured the prescribed volume of PAG oil into that,  re-evacuated with the vacuum pump, re-checked that it holds vacuum...  then filled with 27 ounces of R134a as in the manual.

Has been working correctly since then. 


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Re: Air Conditioner Repair - Gen 2.5
« Reply #5 on: May 10, 2018, 09:38:19 PM »
Good to hear. Monteros don't use an orifice tube, they have expansion valves, which are inline and located in the evaporator. Half the time, aftermarket suppliers sell you the wrong part and as a result, I've never replaced one. Excellent move replacing the receiver/drier.

Always use the green O-rings made from Viton, and lubricate them with whatever oil your system uses. Do not overtighten the fittings or they will leak.

Drawing a vacuum serves two purposes, one being a leak-check, but the other is that the closer you get to a "perfect" vacuum, the lower the temperature needed for any remaining moisture in the system to boil out. On a nice hot day like today in Phoenix (+100 F), pulling a deep vacuum will make sure there's no moisture in there to screw things up down the road.

And once again, good on you for metering R-134a carefully to avoid overcharging.

John B.
AZ Crew/East Sider/Former 14th St Crew
95 SR, 35x12.5-15 on 8" steelies, 2" BL, stuff cut off, stuff welded on, lights, sound, front ARB pending
87 Raider, There's a turbo 2.6 under its hood, really
83 "Dodge" Power Ram 50, a bit lifted, way slow and gets more comments from random people than the other two put together
'95 Montero SR. Pretty much stock, Trail Gear Sliders, ADD skid plates, Stereo by Shovel, Timing maintenance by Pa_Jero