Tracking down A/C issue

[dwinters14]

First most likely leak is right at the low side schraeder valve. Get the tool to tighten it. Need to know what your PSI is on the low side with compressor engaged. If compressor isnt engaged thats likely because system pressure is too low. There is a cutoff sensor for low pressure.

Interesting, I'll double check that thank you.

Youve got access to gauges. Use em. If you dont know the pressures you cant diagnose.

Yes. I'm going to do this the old fashion way. Get a gauge reading of the hi/lo with the car off and with it on, with the a/c on. Then i'm going to recover the system, check vacuum, then refill with dye and track down the leak/issue.

 

[rockola1971]

Interesting, I'll double check that thank you.



Yes. I'm going to do this the old fashion way. Get a gauge reading of the hi/lo with the car off and with it on, with the a/c on. Then i'm going to recover the system, check vacuum, then refill with dye and track down the leak/issue.

On a system with a good compressor your pressures should be about the same with system off. This is called equalizing and is normal on any A/C, Refrigeration system. What you really need right now is the low side pressure reading with system on and clutch engaged on compressor (compressor pumping) so we can help you better trobleshoot.
But it does sound like you probably have a leak. So I would fix that first and to verify its fixed once youve replaced the leaker you will need to pump system down and then let it sit for atleast 30mins to see if the vac gauge moves any which would indicate a leak. I like to pump down for a good hour if i have to open the system up. That way I know any moisture in the system is boiled out. Moisture is the enemy in a a/c system. Think of it like this. Wherever there is water in a refrigerant system, that causes refrigerant to not be able to take the physical place the water is. 2 things cant be in the same exact place at the same time! Water causes funky problems when in a ac system. It will even trick you vac gauge. If you have no leaks but have moisture in the system. The second you turn the vac pump off the needle will jump upward toward atmospheric pressure. Usually not alot but very noticeable. If it does that then you got some more pumping down to do to boil that moisture out.

 

[OneofFew]

Whenever working on these and you know you have little or no pressure, I always replace both the low and high side service valves. Too many times they ended up leaking after charging r134.

 

[rockola1971]

Whenever working on these and you know you have little or no pressure, I always replace both the low and high side service valves. Too many times they ended up leaking after charging r134.

A common culprit on the low size is when the charge house that attaches to a 12oz can is used it will tend to loosen the schrader valve as the hose fitting is rotated during filling of the system. Then there is just dried out seal on the valve itself being the cause of the leak also.

 

[dwinters14]

On a system with a good compressor your pressures should be about the same with system off. This is called equalizing and is normal on any A/C, Refrigeration system. What you really need right now is the low side pressure reading with system on and clutch engaged on compressor (compressor pumping) so we can help you better trobleshoot.
But it does sound like you probably have a leak. So I would fix that first and to verify its fixed once youve replaced the leaker you will need to pump system down and then let it sit for atleast 30mins to see if the vac gauge moves any which would indicate a leak. I like to pump down for a good hour if i have to open the system up. That way I know any moisture in the system is boiled out. Moisture is the enemy in a a/c system. Think of it like this. Wherever there is water in a refrigerant system, that causes refrigerant to not be able to take the physical place the water is. 2 things cant be in the same exact place at the same time! Water causes funky problems when in a ac system. It will even trick you vac gauge. If you have no leaks but have moisture in the system. The second you turn the vac pump off the needle will jump upward toward atmospheric pressure. Usually not alot but very noticeable. If it does that then you got some more pumping down to do to boil that moisture out.

Thank you for all the great advice.

Whenever working on these and you know you have little or no pressure, I always replace both the low and high side service valves. Too many times they ended up leaking after charging r134.

This was the type of quirky I was looking for. I'll change both valves/seals before I re-pressurize the system.