A/C woes: low pressure switch

[JKP]

The schrader valve probably just needs to be tightened down with a valve core tool. But they can go bad. It won't hurt anything if it's loose/bad, but as you found out will leak when you remove the switch.

I don't remember exactly what it looks like in there, but the o ring would go where the switch mates to the line. If it's not leaking there, you got it in the right spot. The

 

[Johnnyswell]

The schrader valve probably just needs to be tightened down with a valve core tool. But they can go bad. It won't hurt anything if it's loose/bad, but as you found out will leak when you remove the switch.

I don't remember exactly what it looks like in there, but the o ring would go where the switch mates to the line. If it's not leaking there, you got it in the right spot. The

Okay this is at least good news that I either need a new Schrader valve or it needs to be tightened down. I spoke to my mechanic and I might have him drain the system on Thursday and replace the Schrader valve with a new one and replace the o-ring again, then refill the system. Any recommendations on what to refill the system with? I've heard specific refrigerant can keep the cabin cooler than others?

 

[MBDIAGMAN]

Oh, glad I asked. Any other grease you may recommend maybe as an alternative?

There is a special lubricant that can be used for refrigeration o rings, but there’s no need to track it down for one time use. Just clean your hands well, clean the mating surfaces well and put a little PAG or Ester on the area and assemble. If you use PAG, wash your hands afterward.

The special assembly lube comes in a refrigeration o-ring kit that is very useful to have around if you do even a little bit of a’c work.

 

[MBDIAGMAN]

Okay this is at least good news that I either need a new Schrader valve or it needs to be tightened down. I spoke to my mechanic and I might have him drain the system on Thursday and replace the Schrader valve with a new one and replace the o-ring again, then refill the system. Any recommendations on what to refill the system with? I've heard specific refrigerant can keep the cabin cooler than others?

I wouldn’t do that. If it is not leaking and the switch is working, leave that dog alone. The only need for the shraeder valve is to contain the charge when youre changing the switch.

Also, it is illegal to “drain” the system. If you want to remain legal, the charge must be recovered, and the system properly evacuated to have proper operation and prevent moisture from entering the system. Moisture combines with refrigerant to make an acid which will destroy the system from the inside out.
Dont empty a refrigeration system unless you have a very good reason to do so and have a way to evacuate it before recharging.

Hope this helps.

 

[JKP]

Okay this is at least good news that I either need a new Schrader valve or it needs to be tightened down. I spoke to my mechanic and I might have him drain the system on Thursday and replace the Schrader valve with a new one and replace the o-ring again, then refill the system. Any recommendations on what to refill the system with? I've heard specific refrigerant can keep the cabin cooler than others?

R134a. Don't use any with stop leak in it. Dye is OK if you think there might be another leak.

 

[txbemis69]

When you swapped out the low pressure switch did you have to evacuate the system? I bypassed my low pressure switch and the compressor turns on. Pressure seems good. When I went to start taking off the low pressure switch it started releasing refrigerant from the line (I’m guessing) so I quickly tightened back the old one. Does it leak out all of the refrigerant?

i unscrewed the old one and then screwed the new one on. it hissed just a little bit but, that’s it.