How to fix leaking air conditioning schrader valve

[loonytoon500]

I have a 98 jeep cheerokee sport. The air conditioning coolant leaks. After doing some diagnostics, I detected audibly a hissing sound coming from the low input port, leading me to believe the schrader valve is leaking.How do I determine which valve core remover tool fits my vehicle? I have found one from Mastercool and one from Interdynamics. I am pretty sure I bought one of these before and it didnt work, because it supposed that the car had a thread around the outside of the low input port for it to "connect to", whereas on the jeep, there is no thread on the outside of the port, its actually on the inside of the port.

 

[greg92jeepxj]

Hey what's up doc ! Lol . There are people here that can have a lot of fun with your forum name . Hope your up for it. Your 1998 jeep is a factory 134A system therefore there won't be any external thread on either the low or high pressure ports . The only thread you will see is inside for the caps to thread onto . If the Schrader valve(s) have a round pintle , the valve(s) are non-serviceable. If they are elongated like a tire valve , they should unthread . I have removed them using a simple valve core removal tool for tires . If you have one , see if it fits onto the valve and will unthread , but it must be like a tire valve or no go . Be advised , if pressure exists in the system , you MUST have the freon recovered as you cannot remove this valve until the freon is discharged . You do not want to release freon into the atmosphere. That is irresponsible.
To replace a serviceable valve , it will be just like replacing one in a tire valve , but you must use a valve for 134A or the PAG will erode the valve seal . Hope this helps . Greg

P.S. - if the valve is unserviceable , unfortunately , I believe the only repair is to replace the line as I am not aware of any procedure to replace a valve core that won't unthread .

 

[loonytoon500]

Hey Greg, thanks for the response. What does it mean (how can I tell) if the schrader valve has a round pintle? Im pretty sure the jeep has the schrader valve that came with the car (stock).

Incase it helps, here is a picture of the schrader valve:


And here is one of the cap:


Before I manage to get it out, what size/kind of schrader valve i need to pickup at the auto parts store? Is it the standard r12/134a valve core, as in this kit? Mastercool 91337 R-12/R-134a Valve Core Repair Kit : Amazon.com : Automotive
I dont plan to buy the kit, just posted the link for referencing the pic there (the valve core to the left most slot)

 

[greg92jeepxj]

Thanks for the pics . It looks to me that you have serviceable valve cores , but to be sure , you will have to try to unthread them. If you can fit the valve core tool ( the ones for bicycle tires should work) over the flat sides , you can unthread them. But do not try to remove completely , there is freon under pressure in the system , just see if they loosen. Do not force , they should loosen with reasonable pressure. If the bicycle valve core tool cannot reach down far enough , you will need the a/c valve core tool. From the looks of the picture , I think you can. Caution : do not stand too close when trying to insert tool and unthread , you don't want to get blasted with freon ! Careful when inserting tool to check fit and careful attempting unthreading. If it will not move , do not force it . The threads go deep which should mean the valve core should unthread . If the threads were shallow , it would be unserviceable . Check to be sure , be careful not to force it .
make certain to keep the area inside and outside the port(s) clean.

 

[greg92jeepxj]

Forgot to answer question about round pintle. If the top of the pintle looked like a mushroom and is too wide to insert a tool over , that would be an unserviceable valve core. Your valve core appears to be the same as found on a tire which are removeable. On some vehicles , unserviceable valves are purposely installed to prevent tampering . That makes the repair expensive as the line must be replaced. Over zealous a/c repairs with dial down quick disconnects bend these valves , necessitating replacement. That's why I like to do my own. Flush , blow out with compressed air , vacuum and install freon. Be advised , some parts cannot be flushed. Never flush a compressor , expansion valve accumulator or drier.
Some condensers , evaporators , lines , etc. cannot be flushed because of design and flush cannot be removed easily , even with compressed air.

 

[joecook]

I have a 98 jeep cheerokee sport. The air conditioning coolant leaks. After doing some diagnostics, I detected audibly a hissing sound coming from the low input port, leading me to believe the schrader valve is leaking.How do I determine which valve core remover tool fits my vehicle? I have found one from Mastercool and one from Interdynamics. I am pretty sure I bought one of these before and it didnt work, because it supposed that the car had a thread around the outside of the low input port for it to "connect to", whereas on the jeep, there is no thread on the outside of the port, its actually on the inside of the port.

I think your jeep model is very old. So you should hire an expert professional who has a good knowledge about air conditioners. You may also watch some air conditioner repair guide videos on YouTube. You may get some help from heating hudson county nj team’s site, they provide some useful suggestions which will help you out.

 

[greg92jeepxj]

I would like to add to member joecook's post that while safety should always be taken first before trying to take on any repair or any work to your vehicle , I won't discourage anyone from trying to do the job themselves. Reading back over my own replies , I realize I did not warn to check if system is pressurized and that any disassembly must be done AFTER the system is discharged.
Regret error in posting. As far as the system being too old to be serviced by a DIY'er , I beg to differ. My jeeps air conditioning system (1992) was last serviced,by me with not much more than common hand tools , a manifold gauge set and proper adapters where called for , and a vacuum pump. A vacuum pump is an investment some are not willing to make and therefore would rather pay for the service but my pump has paid for itself many times over to date. I leave the choice to the individual . If you feel it will truly be a one time repair , the professional may be the best choice . If you like to do your own and perhaps service other vehicles then maybe investing into a gauge set and a vacuum pump will best suit you. I say this to all now since the thread we are posting on is almost one year old . I believe you can always teach an old dog new tricks.