A/C question 328

[kholt]

hi people,

so last summer the a/c stopped being cold. i followed advice of previous posts and recharged myself to the recommended pressure (it took less than one tall can) using pressure gauge that came with the can. got cold air for a while but then stopped again maybe 1 week later. the port (the one towards the windshield end of engine) where i added the freon still has high pressure, but the port at the other end has little pressure.

Is it possible I need to put more freon in the system? As I understand, if I overcharge that may cause damage. I would think if I have a leak, there wouldn't be pressure at the input port.

thanks

[witeshark]

It would seem there is a small leak that needs to be fixed.

[kholt]

thanks, but why is the pressure high? if a small leak, shouldn't the pressure drop and it would take more gas? if i add more gas, it seems the pressure will go too high above the recommended pressure.

[witeshark]

I really dunno about the pressure difference. But I think the system needs to be tested and serviced rather than simply adding refrigerant.

[darkhorse737]

you have 2 ports in an A/C system.. a high pressure port(up to 250psi); and the low side port(around 25-40psi) depending on how much freon is in your system, and depending on how efficient your compressor is.

If you have lost freon and need to re-charge, it simply means that you have a system leak somewhere. Knowing that, a "re-charge will only give u a temp remedy - it being that when u have a leak, air/moisture also seeps into the system thereby making your system inefficient(freon and air/mosture don't like each other).

ood way to do your repair. Have your system vacuumed(old freon evacuated) and then recharge to specs using the newer R134a freon cans that contain a "stop leak" solution, and a dye tht can help u identify where the leak might be at a future time :-)

[kholt]

thanks again.

i don't know much about this subject. i don't see anything in my bentley manual in regards to ports and pressures.

Am I supposed to refill at the high pressure port or low (i was told high and fill to about 35 psi, which sounds wrong based on what darkhorse said)?

From what I've heard, the system needs to recharged periodically even without an actual leak (in other words, even a sealed A/C system has expected normal leakage over time). True/false?

[darkhorse737]

low side pressure port( the blue covered port) should have read around 35psi.

From what I've heard, the system needs to recharged periodically even without an actual leak (in other words, even a sealed A/C system has expected normal leakage over time). True/false? <<< FALSE. You look at A/C in much the same way as your house refrigerator. If we go by what you heard, the it means tht we have to recharge our refs periodically??? tht doesn't sound right does it?... considering that A/C and refrigeration operate based exactly the same principles :-)

[kholt]

thanks for your time darkhorse

so where should freon be added - low or high pressure port?

[darkhorse737]

always the LOW side for charging. In 134a systems, that would be the smaller of the ports, or the one that has the BLUE cover.

TIP: the HIGH side port is used only for testing efficiency of the compressor