92Q, 110K - seems like the A/C is not cooling enough - wife and kids have refused to sit in this car ... this is perhaps a blessing in disguise, but the AZ heat is difficult to bear w/o the AC system at its best.
I did the autonomic tests illustrated in the maual - the systems checks out okay (using the control panel switches - internal air passage doors appear to be working alright, codes come okay).
I took the car to a local A/c shop, he stated that freon is full. The A/C does cool the air, but does not make it comfortable for AZ mid day heat. Also, takes some long time to start feeling the cooling effect.
Any leads folks?
Thanks
A/C not cooling in AZ sizzling summer
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
You must provide Accurate ambient temperature and Accurate center outlet temperatures after the Q has been going 15 minutes at 60 mph.In 90 F ambient the center outlet should be 47-50-51F on highest speed recirculation closed [temp set at 65F] with 1 person on board. {each human body decreases the system capacity by 2%].At 110F it would be around 62F. This might result in an average 80F-83F interior temperature depending on car color and solar radiation index [clear non haze sky].
Generally if the R12 charge is a perfect 1.1 Kg, the root cause is decreased efficiency caused by dirt on the condenser, between the condenser and radiator, [things that decrease air flow] [auxillary fans not working , not working on high speed], An aged evaporator may be partially air blocked, a compressor may be worn affecting the pressures. There may be too much moisture in the system from not changing dryers every 60k or 4 years.
What you must do is install a high pressure gauge and tape to windshield to read and record the pressure in differing situations.
Kind of late to begin what happened to the annual test in April in preparation.
The system is designed to transfer 500 BTU per minute to the condenser air flow at 2,000 rpm [60 mph] at idle it is about 1/2 this amount.
Also it would be helpful if after what ever minimum the center vent reachs you pull over in park and log the temperature rise every 30 seconds for 10 minutes to build a graph [log the changes in ambient sensor readings at the same time.
These are the things/ways engineers approach the problem that AC techs ignore [never learned].The interior volume is constant and so is the fan speed so the temp rise tells us BTU of cooling.
Generally if the R12 charge is a perfect 1.1 Kg, the root cause is decreased efficiency caused by dirt on the condenser, between the condenser and radiator, [things that decrease air flow] [auxillary fans not working , not working on high speed], An aged evaporator may be partially air blocked, a compressor may be worn affecting the pressures. There may be too much moisture in the system from not changing dryers every 60k or 4 years.
What you must do is install a high pressure gauge and tape to windshield to read and record the pressure in differing situations.
Kind of late to begin what happened to the annual test in April in preparation.
The system is designed to transfer 500 BTU per minute to the condenser air flow at 2,000 rpm [60 mph] at idle it is about 1/2 this amount.
Also it would be helpful if after what ever minimum the center vent reachs you pull over in park and log the temperature rise every 30 seconds for 10 minutes to build a graph [log the changes in ambient sensor readings at the same time.
These are the things/ways engineers approach the problem that AC techs ignore [never learned].The interior volume is constant and so is the fan speed so the temp rise tells us BTU of cooling.
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AZhitman
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I concur. My Q sometimes gets too cold, even well over 115 degrees ambient outside temp.
The dark color may make a difference though. Also, I am thinking your condnsr is unable to release the heat into the atmosphere if the radiator is overheated (even by few degrees).
When was the radiator flushed and t-stat changed last?
The dark color may make a difference though. Also, I am thinking your condnsr is unable to release the heat into the atmosphere if the radiator is overheated (even by few degrees).
When was the radiator flushed and t-stat changed last?
hitman, the radiator was flushed (while doing the guides) last November/October. Tstat has not been changed in last 18 months (when was it changed last, I do not know).
The transmission cooler is next to the condenser - could this be a problem?
Would be difficult to see the condition of the condensor w/o removing the transmission cooler - but can be done I suppose.
What is involved and $$ in changing t he dryer - as suggeted by Dennis as a 40K interval requirement?
Thanks
The transmission cooler is next to the condenser - could this be a problem?
Would be difficult to see the condition of the condensor w/o removing the transmission cooler - but can be done I suppose.
What is involved and $$ in changing t he dryer - as suggeted by Dennis as a 40K interval requirement?
Thanks
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
You gotta give us the numbers so we can calculate the defficiency from normal.
AC is so simple, every car now has one, but you would be surprised that only 1 out of 20 shops really know what they are doing. Oh, they know how to change parts, but engineering is beyond them.............and rightly so since they just fix them.
Life extension is more a science and shops are never asked to do preventative maintenance.
Which is why we {I} get so much resistance about dryer replacement..........the other reason is they [the shops] only see the pressure values in the shop. They would never consider driving around in traffic [hood closed] with gauges attached [the real world situation.
Many Q AC system get funky after 20-30-45 minutes of operation [the tiny amounts of residual moisture in the system reduce the cooling action as the inside temperature drops]..........the difference in 47F vs 51F [10% decrease in performance]..........3,000 BTU/hr is enough to cool or not cool [compensate for] 5 large adults.
Sometime the evacuation machines don't have the capacity [can't vacuum the system down to the correct {torr/microns] to get the moisture to boil out completely, or they are rushed and don't leave the machines on long enough.
http://www.griffiths.com/porsche/ac/ice ... io...e.htm
AC is so simple, every car now has one, but you would be surprised that only 1 out of 20 shops really know what they are doing. Oh, they know how to change parts, but engineering is beyond them.............and rightly so since they just fix them.
Life extension is more a science and shops are never asked to do preventative maintenance.
Which is why we {I} get so much resistance about dryer replacement..........the other reason is they [the shops] only see the pressure values in the shop. They would never consider driving around in traffic [hood closed] with gauges attached [the real world situation.
Many Q AC system get funky after 20-30-45 minutes of operation [the tiny amounts of residual moisture in the system reduce the cooling action as the inside temperature drops]..........the difference in 47F vs 51F [10% decrease in performance]..........3,000 BTU/hr is enough to cool or not cool [compensate for] 5 large adults.
Sometime the evacuation machines don't have the capacity [can't vacuum the system down to the correct {torr/microns] to get the moisture to boil out completely, or they are rushed and don't leave the machines on long enough.
http://www.griffiths.com/porsche/ac/ice ... io...e.htm