M
Mike Bender
Hi all...
After the weather started warming up here I began noticing that my
'03 Forester's AC wasn't blowing cold (barely below ambient) and an
annoying hissing sound was coming from behind the dash. Suspecting a low
refrigerant charge and not wanting the compressor to eat itself I
disconnected it until I was able to borrow a manifold gauge set and check
things out. The last time I worked on a car AC system was back when R12
was still legal and a recharge meant checking the site-glass for bubbles
while you put in a can or two of refrigerant. Anyway, I figured I'd try
my hand at an R134a system and hopefully not break anything. When I
hooked up the gauges I found low pressure on both sides of the system (in
fact the low pressure side would pull a vacuum when the compressor ran).
Figuring a low refrigerant charge was the issue, I put in a can of
refrigerant/lubricant/sealant. After this the vents were blowing air in
the temperature range I thought they should. When I checked with the
gauges the pressure was better, but I'm still not sure it's right. The
low side would read upper 20's (psi) and the high pressure side would
read about 175 psi with the engine running, but the compressor clutch
disengaged. When the compressor would kick on, the low side would drop
down to about 10-15 psi and the high side would get up to about 220 psi
at which point the compressor would cycle and the pressures would
rise/drop to their initial values. So I have the following questions for
anyone with more experience in this area than myself:
1) Is what I'm seeing with the pressures normal? The shop manual I have
didn't say anything about the pressures being either steady or varying -
just provided a range (18-28 psi low side, 213-242 psi high side). Do the
pressure swings on the gauges indicate a problem somowhere? At this point
I'm thinking the system is touch low of refrigerant but am reluctant to
tap another can just to top up the system. Could leaving the charge a
little low cause problems?
2) When I first removed the screw cap from the high pressure side of the
system, there was a small gas release and the inside of the fitting was
wet with oil. Is this normal or do I have a bad schraeder valve? The
paranoid side of me is wondering if the last time I had it in the shop
for a non A/C matter if someone there vented my refrigerant charge as an
attempt to drum up future business. If a little leakage of refrigerant
and oil through the high side valve is normal, then I can straighten my
foil hat and get on with my life.
3) Is refrigerant leakage from Subaru air conditioning systems like this
normal? Should I just plan to periodically recharge it or do I need to
have it checked out by a pro?
Any information would be appreciated.
Ad<thanx>vance
- Snuffy -
After the weather started warming up here I began noticing that my
'03 Forester's AC wasn't blowing cold (barely below ambient) and an
annoying hissing sound was coming from behind the dash. Suspecting a low
refrigerant charge and not wanting the compressor to eat itself I
disconnected it until I was able to borrow a manifold gauge set and check
things out. The last time I worked on a car AC system was back when R12
was still legal and a recharge meant checking the site-glass for bubbles
while you put in a can or two of refrigerant. Anyway, I figured I'd try
my hand at an R134a system and hopefully not break anything. When I
hooked up the gauges I found low pressure on both sides of the system (in
fact the low pressure side would pull a vacuum when the compressor ran).
Figuring a low refrigerant charge was the issue, I put in a can of
refrigerant/lubricant/sealant. After this the vents were blowing air in
the temperature range I thought they should. When I checked with the
gauges the pressure was better, but I'm still not sure it's right. The
low side would read upper 20's (psi) and the high pressure side would
read about 175 psi with the engine running, but the compressor clutch
disengaged. When the compressor would kick on, the low side would drop
down to about 10-15 psi and the high side would get up to about 220 psi
at which point the compressor would cycle and the pressures would
rise/drop to their initial values. So I have the following questions for
anyone with more experience in this area than myself:
1) Is what I'm seeing with the pressures normal? The shop manual I have
didn't say anything about the pressures being either steady or varying -
just provided a range (18-28 psi low side, 213-242 psi high side). Do the
pressure swings on the gauges indicate a problem somowhere? At this point
I'm thinking the system is touch low of refrigerant but am reluctant to
tap another can just to top up the system. Could leaving the charge a
little low cause problems?
2) When I first removed the screw cap from the high pressure side of the
system, there was a small gas release and the inside of the fitting was
wet with oil. Is this normal or do I have a bad schraeder valve? The
paranoid side of me is wondering if the last time I had it in the shop
for a non A/C matter if someone there vented my refrigerant charge as an
attempt to drum up future business. If a little leakage of refrigerant
and oil through the high side valve is normal, then I can straighten my
foil hat and get on with my life.
3) Is refrigerant leakage from Subaru air conditioning systems like this
normal? Should I just plan to periodically recharge it or do I need to
have it checked out by a pro?
Any information would be appreciated.
Ad<thanx>vance
- Snuffy -