Automotive Air Conditioning Information Forum

Hi I am looking for help with learning how to properly and safely pull and replace and recharge my expansion valve in my 2004 jeep grand Cherokee 6 cyl 4.0 l
I am seeing the low side pressures holding steady at 5 psi and the high side holding at 225 psi?? expansion valve is the cheapest thing to start with right? I really could use step by step instructions on how to do this. do I need to evacuate? how does a diy do that all I see in the parts stores are vac systems but my understanding is that these are to only remove moisture after the repair and just before recharging?????????? Help!!!!!!

Yes, you would need to have your refrigerant recovered first.

Recover charge, remove lines to TXV, remove TXV from Evap inlet, replace with new one- mount lines, evacuate system for 15 minutes, and recharge to factory spec- should take 30 minutes max. if you have a recovery, recycle, recharge machine available.

How do you know you have a bad TXV? The most important thing is to have the correct amount of refrigerant--why not charge it to factory spec by weight and then see what the low side does? My gut feeling is that you are running on about half a charge....

could I add some to tell that? why do you think that? how could I verify if the valve is good? I am basing it from my low side reading 5 psi and high 225

GM Tech wrote:Recover charge, remove lines to TXV, remove TXV from Evap inlet, replace with new one- mount lines, evacuate system for 15 minutes, and recharge to factory spec- should take 30 minutes max. if you have a recovery, recycle, recharge machine available.

How do you know you have a bad TXV? The most important thing is to have the correct amount of refrigerant--why not charge it to factory spec by weight and then see what the low side does? My gut feeling is that you are running on about half a charge....

You can try--- 65% of all mobile a/c failure is due to loss of refrigerant due to a leak- according to my 5,000+ database- so you play the odds...but to be sure you must have the factory specified amount of refrigerant in the system before you even consider reading pressures....My first step is always, pull and weigh the refrigerant in the system-- then put in proper amount, then diagnose........

thanks for the info....
if you hooked up gauges and read the low 5psi and the high 225psi with a vent temp of 60 on a 90 degree temp what would you still think there may be a leak?

yep!

If it's a pressure controlled electric condenser fan you can easily see a 225 high side with a low charge. This is because the fan stays off until the trip pressure is reached, allowing the condenser to get very hot.

Don't add any sealer or any refrigerant that contains sealer, you'll ruin the system forever !!!

I appreciate everyone's input! if anyone has anymore suggestions please let me know!