About a few years the A/C in my familys 1996 Caravan (front A/C only) has slowly stopped working. It has been recharged by a mechanic twice, but slowly leaks out and before the last time at the mechanic My dad tried adding R134A refrigerant to the low pressure side, but it would not take it and followed all the directions.

So we drove with out A/C for a year and now it is time to get serious.
When the A/C would slowly stop running as cool as it used to I could always hear a light hissing sound from right around behind the glovebox area and thought the evaporator coil was leaking.

Im a beginning mechanic myself for only 2 years and only experienced with engines, but I am doing a lot of research and read these 2 threads on here (https://dodgeforum.com/forum/dodge-c...-pictures.html https://dodgeforum.com/forum/dodge-c...-problems.html) which is why I am asking here for help.

I suspect that the thermal expansion valve is stuck or leaking and needs to be replaced. I will also replace the receiver drier once I know which one to get. I doubt there is any pressure inside the system after a year and a half, but I will get it discharged before I am sure that the valve is the problem. I hope it is, because I am not going to teardown the dashboard to replace the evap-coil. Just don't use the van for long trips in the summer

I bought a can of 134a refrigerant and a leak detection kit that I will try to do this weekend or so, but I read that the detection kit with the sealant will cause more problems than it is worth and I can't find a can with out the sealant. If that don't work then I will have to fork out more money to the dealership and ask them to find where it is leaking from. I can do it myself, just I want to make sure im fixing the right part.

 

Welcome to DF
Before replacing any parts I would service the system and add dye to the a/c and check for any leaks.

 

Thanks, I hope it shouldn't cost more than a couple of $100s and might be able to replace the part if it isn't too hard to do. Then bring it back and have them recharge it.

Also what is that black **** part on the large line going to the H-valve?

 

Large line is the suction line. the smaller one is the liquid line. your dad probably tried to put it in the liquid line lol that wount work. if you have some pressure it aint going to remove it out of the can. you need to put it on the suction line so it sucks it in. First this hissing does not always mean theres a leak. 3 things it can be a. leak lol b. short on gas c. metering device metering the refrigerant. first step to do is find the leak and repair it. then do the filter/receiver. check the orfice on the metering device. it has a screen to pick up metal fragments. if lots then you got more issues. vaccum properly system and charge to CORRECT charge. done

 

Ahh I think he did put the can on the smaller line lol. I will tell him to try the large side. Where would the orifice be? and the screen.

 

not sure on this vehicles cause im hvac/r mechanic not car but ive seen a few cars that ussually after the reciever they have that connection ya need the tool to remove. spread the lines and usually u see in the line. unfortunately this i caint help you on. ussually its a metering devices aswell with a built in screen

 

on your 96 the suction side fitting isnt so easy to get at. its about midway down the passenger side of the rad, watch your can while charging as it can easily fall into the rotating belts.(a piece of wire helps)

its typicall to hear a hissing inside the car providing its not constant as the refrigerant makes noise going into the evap.

most likely places for leaks
condensor
line joints
compressor (Orings in line ends and front end)

get a can of dye and u should be able to find the leak.

 

Most likely cause of the leak is the evaperator. They went bad all the time.

 

Yeah I saw that one it is by the passenger tire I believe. That is the correct line, because the person above me told me that is the wrong one. I want to make sure so I dont put a can on the high pressure side

Going to try to find that leak this weekend and or bring it to the dealer to have it properly charged and inspected, unlike my dad brought it to a local shop before.

 

A few more questions that made me curious. I like to learn

This is where to add refrigerant? Circled in blue
I bumped this cheaply plastic box and looks like it has something to do with the A/C. What is it?
and a sensor of some sort is going to one of the lines which also goes to that plastic box. What is that too and is it a low pressure sensor? Circled in green and the wire going to the box in red.