ac question

zmt325

zmt325

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i have purchased one of those walmart r134a cans with a gauge on top. i put about 2/3 of a can in, it read good pressure on the gauge like 35-40 psi but the compressor did not kick on :mad:.

so I jumped the low pressure switch that is on top of the ?condenser? (the can looking thing) the compressor kicked on.:D i let it suck the can dry. now when the compressor is running it reads 0psi when i pull my jump wire and turn it off the pressure reads in the red :confused:

also the compressor cycles for like 5 sec max and then cuts off when plugged into the lpss. I can watch the gauge jump from high 100 psi to almost 0 as it cycles

so wtf is going on is the static pressure of 100 psi normal?
I feel like I need to put more in it, but 100 psi scares the :q:q:q:q outta me expecially when the gauge says WARNING on it at 65 psi
 
something is kaka.

first off, 100 psi when system is off is not unheard of, mine is usually 80-90 without compressor running,means nothing really.
the 65 psi warning and red zone are meant to be read only while comp is actually running.

but getting 0 psi when running and the fact you have to jump the wire/plug to engage the comp. is not good.

either you have a bad expansion valve or other type of component failure, blockage in the system somewhere, orifice tube etc. OR

the guage on the can may be bad. but with a full can in and 100 psi static, i would expect the compressor to run atleast a little on its own.

when you force the comp. to engage is there any cooling at all?

ps. the "can looking " thing with the low pressure switch is the accumulator/drier.
the condensor is up front with the radiator and the evaporator is in the dash/firewall area with your heater core.
 
thank you moes it will kick on and cycle by it self for like 2-3 sec and then off for 5. now that you have told me the static pressure is ok at 100psi i am going to get another can today.

EDIT: freon is leeching out the low pressure petcock valve. it only read 30 psi when i tested it after 8 hours of sitting, used 2 more cans to get the compressor to stay on without cycling static pressure is at 90 psi now

anyone know a quick fix for the valve problem? i am leaving the gauge on it for now
 
Last edited:
Sapperfire said:
yeah, replace the valve
Click to expand...

kinda what i thought did not know if there was a short cut. looks like i will be evacuating the system this weekend, replacing the valve and recharging. I am lucky to have a retired Nissan mechanic as a friend he has every tool + a world of knowledge.

thanks sapper
 
There is a tool to replace the schrader valve core without evacing the system. If you go to a place that does a/c or someone that does resi service they will most likely have the tool and you can get it done for like a beer or something.
 
zmt325 said:
thank you moes it will kick on and cycle by it self for like 2-3 sec and then off for 5. now that you have told me the static pressure is ok at 100psi i am going to get another can today.

EDIT: freon is leeching out the low pressure petcock valve. it only read 30 psi when i tested it after 8 hours of sitting, used 2 more cans to get the compressor to stay on without cycling static pressure is at 90 psi now

anyone know a quick fix for the valve problem? i am leaving the gauge on it for now
Click to expand...

this isnt the real answer you need, but i was wondering, do you have the cap that belongs on it?
i had a car once that had the same problem,but as long as the cap was on tight it didnt leak.

some caps might leak though.

+1 on getting the schrader valve core replaced
 
Moes8 said:
this isnt the real answer you need, but i was wondering, do you have the cap that belongs on it?
i had a car once that had the same problem,but as long as the cap was on tight it didnt leak.

some caps might leak though.

+1 on getting the schrader valve core replaced
Click to expand...

sadly the system naturally evacuated it self so i went to the dealership and bought the new schrader valve and installed it today. I also bought my own set of gauges, leak detection kit, more r134 and vacuum pump. i am going to pull a vacuum first thing tomorrow to make for certain that was the only leak, cross my fingers and charge it again
 
ahh sweet sweet cool success
158.jpg
 
come by the shop this weekend and i will put a vacuum on and charge it for you. pm me for the address its $45 for the freon. i would go ahead and replace the high and low side schrader valves another $30.
 
30 degrees? how hot was the ambient when you shot that?

is that vent temp?

i cant get below 45 on my vents at around 90 degrees outside.
 
Yeah that seems too cold of a reading.

I thought my 92 Cavalier with R12 at 38F was cold as hell. I couldn't keep my fist in front of the vent anymore than 30 seconds
 
it was 90+ and yes that is vent temp, it was with an infrared thermometer basically shooting at the back of the vent, it will freeze you out
 
Moes8 said:
this isnt the real answer you need, but i was wondering, do you have the cap that belongs on it?
i had a car once that had the same problem,but as long as the cap was on tight it didnt leak.

some caps might leak though.

+1 on getting the schrader valve core replaced
Click to expand...

thats because the cap is actually the PRIMARY seal, and the valve is the secondary
 
Man that's a awesome deal...anybody near detroit with that type of deal?
 
zmt325 said:
it was 90+ and yes that is vent temp, it was with an infrared thermometer basically shooting at the back of the vent, it will freeze you out
Click to expand...
+1

I was gonna call BS too but just went out and tested mine. Its currently 100* outside with a heat index of 104* and 48% humidity. Nose of the car in direct sunlight and no wind. After 3 minutes the vents dropped to 31* and held there.
I never thought to test my AC before with my temp gun in this car. I have in previous cars and never saw them drop lower then 46* and my houses never drops below 60* (unless at night then its 54*)
 
Sapper, saying the cap is the primary seal is like saying the valve cap on your tire is the primary seal, same thing different application.
 
LSC HUNTER said:
Sapper, saying the cap is the primary seal is like saying the valve cap on your tire is the primary seal, same thing different application.
Click to expand...
The caps on an R134 system are in fact the primary seal.

First time he told me I thought he was full of poopies but then looked it up. Several online AC forums say it is the primary seal.
 
LaserSVT said:
The caps on an R134 system are in fact the primary seal.

First time he told me I thought he was full of poopies but then looked it up. Several online AC forums say it is the primary seal.
Click to expand...

i believe it too, i hand tighten mine,and then can barely remove them by hand later, plus they have a nice rubber bladder seal in the end,plus,like i said above, i had it seal my old car basically for years, as long as it was on,it didnt leak any.
 
to end this thread it turned out my compressor was beaten to death by my addco 1.25 bar. even after putting a vac on it for an hour and letting it sit, it did not drop, therefor i could not tell there was a problem. it stayed cold for 2 days. luckily i am giving up on the 93. kinda sux cause it is sooooo clean inside. and only has 125k, but the black one i bought is fuggin gawjus
 
Well I'll be. I have always dealt with the cap as a secondary seal even with the rubber seal be it R12, R22, and the rest of them. Always used a bit of leak lock on the threads just in case.
 
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