How cold should ac blow--help
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 797
Likes: 10
From: Upper West Side, NY Very Downtown Houston, TX
How cold should ac blow--help
I have a question regarding the A/C.
I just got my car back from a tuner who had an A/C line break while upgrading my headers to a bigger primary diameter.
He replaced the line and charged the A/C, but maybe it’s just me, but the A/C does not feel nearly as cold when it is set to 74 like I always have it set.
I do not have equipment to verify the pressures on the high and low side, but when the A/C is set to reticulate and is on max (60 degrees), the coldest air blowing out is 60 degrees at idle after 5 minutes plus. Is this normal, or should it be blowing colder like 50 or 40 degrees?
The problem is when it is set to 72 degrees, it feels like it is not blowing cold enough to bring the cabin temp down to 72 degrees.
I need this information before I go back to the vendor. Thanks in advance.
I just got my car back from a tuner who had an A/C line break while upgrading my headers to a bigger primary diameter.
He replaced the line and charged the A/C, but maybe it’s just me, but the A/C does not feel nearly as cold when it is set to 74 like I always have it set.
I do not have equipment to verify the pressures on the high and low side, but when the A/C is set to reticulate and is on max (60 degrees), the coldest air blowing out is 60 degrees at idle after 5 minutes plus. Is this normal, or should it be blowing colder like 50 or 40 degrees?
The problem is when it is set to 72 degrees, it feels like it is not blowing cold enough to bring the cabin temp down to 72 degrees.
I need this information before I go back to the vendor. Thanks in advance.
Instructor
Joined: Feb 2007
Posts: 115
Likes: 9
From: Tampa FL
The AC output temp is a function of the input. In general, the warmer, and more humid the air, the less cool the output. For me living in Florida, driving down the road at 90F temp and 90% RH, and the recirculate inside air selected, I get an output temp of 40F.
I'm not an AC specialist or mechanic, so others correct as necessary.
I'm not an AC specialist or mechanic, so others correct as necessary.
Burning Brakes
Joined: Aug 2006
Posts: 1,217
Likes: 5
From: Stark County Ohio
Readings below are a small sample from the 2004 service manual. These are maximum output readings.
Readings taken from the center duct after about 5-minutes. Relative Humidity below 40%
66-75°F outside = 46°F
96-105°F outside = 54°F
116-120°F outside = 57°F (Relative Humidity below 30%)
P.S. - Set your temp lower to see the result. I live in Ohio and I set mine to 68 degrees. I have not as of yet tested the output temp.
-
Readings taken from the center duct after about 5-minutes. Relative Humidity below 40%
66-75°F outside = 46°F
96-105°F outside = 54°F
116-120°F outside = 57°F (Relative Humidity below 30%)
P.S. - Set your temp lower to see the result. I live in Ohio and I set mine to 68 degrees. I have not as of yet tested the output temp.
-
Last edited by timemender; Aug 27, 2009 at 12:21 PM.
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 797
Likes: 10
From: Upper West Side, NY Very Downtown Houston, TX
Thanks gents. The help on this forum is outstanding.
Anyhow, yesterday it was 85 degrees when I took the reading, not sure of the humidity. I will try again today and report back.
Anyhow, yesterday it was 85 degrees when I took the reading, not sure of the humidity. I will try again today and report back.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Sounds like it wasn't filled properly to me. Or it's at least possible. If he broke a line he probably should have vacuumed the system before adding new freon. Did he?
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 797
Likes: 10
From: Upper West Side, NY Very Downtown Houston, TX
I dont know. What is the downside if it is not vacuumed? Also aside from vacuuming does anything else need to be changed? Thanks.
Last edited by fallen; Aug 27, 2009 at 04:05 PM.
Safety Car
Joined: Mar 2005
Posts: 3,639
Likes: 8
From: Madison Wisconsin
St. Jude Donor '08
Many moons ago I was GM mechanic and at that time it was determined the air coming out of the vents should be around 30 degrees cooler than the outside ambient air, whatever that may be at the time.
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 797
Likes: 10
From: Upper West Side, NY Very Downtown Houston, TX
Thanks for the rule of thumb--was this on recirculation or with fresh air coming in? Thanks.
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Racer
Joined: Sep 2008
Posts: 414
Likes: 1
HI, How you doing?..I hope a lot cooler today. as far as your A/C goes.
Ok well i checked mine yesterday about 1:00pm, it was about 83 out side with about 40% humidity out and after my vette had the A/C on for like about 5 min. I checked the air temp coming out of the center vent. And it was blowing out air that was reading 46.
So i hope this helps you a little ok.. dbiddle
And it cant hurt just to go back to have him check it..And see what he comes up with..
Ok well i checked mine yesterday about 1:00pm, it was about 83 out side with about 40% humidity out and after my vette had the A/C on for like about 5 min. I checked the air temp coming out of the center vent. And it was blowing out air that was reading 46.
So i hope this helps you a little ok.. dbiddle
And it cant hurt just to go back to have him check it..And see what he comes up with..
Last edited by dbiddle; Aug 27, 2009 at 03:49 PM.
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 797
Likes: 10
From: Upper West Side, NY Very Downtown Houston, TX
HI, How you doing?..I hope a lot cooler today. as far as your A/C goes.
Ok well i checked mine yesterday about 1:00pm, it was about 83 out side with about 40% humidity out and after my vette had the A/C on for like about 5 min. I checked the air temp coming out of the center vent. And it was blowing out air that was reading 46.
So i hope this helps you a little ok.. dbiddle
And it cant hurt just to go back to have him check it..And see what he comes up with..
Ok well i checked mine yesterday about 1:00pm, it was about 83 out side with about 40% humidity out and after my vette had the A/C on for like about 5 min. I checked the air temp coming out of the center vent. And it was blowing out air that was reading 46.
So i hope this helps you a little ok.. dbiddle
And it cant hurt just to go back to have him check it..And see what he comes up with..
Racer
Joined: Sep 2008
Posts: 414
Likes: 1
Burning Brakes
Joined: Aug 2006
Posts: 1,217
Likes: 5
From: Stark County Ohio
Failure to remove all of the moisture will cause massive damage to the system components from corrosion – Corrosion from the inside out – throughout the entire system. Moisture mixed with Freon results in a corrosive compound.
Le Mans Master
Joined: Feb 2006
Posts: 5,267
Likes: 40
From: Phoenix AZ
Cruising down the highway at 70 mph with fan on 4th bar (med) ambient 112 with 14% humidity, mine blows 36 as measured with a digital thermometer. Any car that blows over 46 or so while in recirc on the freeway needs help.
Have not checked at idle.
The higher you set the fan speed the warmer the output will be. Most are measured on high blower, recirc, after about 5-10 min of operation.
Have not checked at idle.
The higher you set the fan speed the warmer the output will be. Most are measured on high blower, recirc, after about 5-10 min of operation.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Ask him to put his findings in writing and take that back to the shop that screwed it up and tell them you want them to cover the improperly serviced AC repairs.
I bet that the AC Shop will want to replace the receiver drier, orifice tube, vacuum the system and recharge. Thats the CORRECT way to repair it. Oh,,,ask him to add oil to the system, You probably lost some during the damage to the line. LOW OIL is BAD!
BC
I bet that the AC Shop will want to replace the receiver drier, orifice tube, vacuum the system and recharge. Thats the CORRECT way to repair it. Oh,,,ask him to add oil to the system, You probably lost some during the damage to the line. LOW OIL is BAD!
BC
Le Mans Master
Joined: Feb 2006
Posts: 5,267
Likes: 40
From: Phoenix AZ
Came home and grabbed the temp gauge......
Ambient 114 a
nd in the garage with no fresh air 11 outside.
At idle with 3 bars fan speed 43, with full fan speed 49-50.
At 1800 rpm 0 mph, 36 on full fan speed. Its even better when moving on the freeway so the condensor can get some air.
Never touched my ac and it rocks. I need to hook up my gauges and write down the optimal pressures its at just in case I ever need to recharge
Ambient 114 a
nd in the garage with no fresh air 11 outside.At idle with 3 bars fan speed 43, with full fan speed 49-50.
At 1800 rpm 0 mph, 36 on full fan speed. Its even better when moving on the freeway so the condensor can get some air.
Never touched my ac and it rocks. I need to hook up my gauges and write down the optimal pressures its at just in case I ever need to recharge
Safety Car
Joined: Mar 2005
Posts: 3,639
Likes: 8
From: Madison Wisconsin
St. Jude Donor '08
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 797
Likes: 10
From: Upper West Side, NY Very Downtown Houston, TX
Ask him to put his findings in writing and take that back to the shop that screwed it up and tell them you want them to cover the improperly serviced AC repairs.
I bet that the AC Shop will want to replace the receiver drier, orifice tube, vacuum the system and recharge. Thats the CORRECT way to repair it. Oh,,,ask him to add oil to the system, You probably lost some during the damage to the line. LOW OIL is BAD!
BC
I bet that the AC Shop will want to replace the receiver drier, orifice tube, vacuum the system and recharge. Thats the CORRECT way to repair it. Oh,,,ask him to add oil to the system, You probably lost some during the damage to the line. LOW OIL is BAD!
BC
I will get the sytem vacuumed. But isn't replacing the drier a huge job?
How come everytime I work on my car, I have no problems? I have done tons of crap including motor rebuilds, replacements, etc. But when I bring my car to someone I have HUGE issues!
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Although plenty of the vendors on here would probably treat it better than I would. Sounds like the shop you took it to wasn't so great.