Outlet temp. range for A/C vents

[radcon]

I know that there are plenty of people here with A/C and refrigeration experience. This is not Porsche related, but has to do with my wife's new car. She took it back to the dealer yesterday to get the permanent license plates put on and get a complimentary detailing. We noticed since day one that the A/C was cool, but definitely not as cold as it should be, especially since we live in Hawaii with 85 degree temps. She told them to check it out and of course they told her the vent outlet temp was within specs at the high end of the range(she was thinking that the high end was good), so she went on her way. She shows me the service printout and it says the outlet temp was 58 degrees. Shouldn't the temp be somewhere in the 40's. Bear in mind that this is a new car, the A/C was on recirc with the fan on high and parked inside a garage. I could see the outlet temp being this high if the car was sitting out in 100 plus degree sun. So to finally get to the question so I have some ammo when I ***** to the service department, are there any professionals who can give me the approximate temp range for a properly operatin A/C system?

[fred cook]

On my 1980 911SC coupe, the A/C outlets will usually measure
about 50 degrees F. on a 100 degree day. A drop of about 45-50 degrees below the ambient temp is not too bad for a 22 year old car. Your new vehicle should be 10-15 degrees cooler.

Good Luck

Fred Cook
'80 SC Coupe

[gr8fl4porsche]

I was wondering why someone was asking about a/c when I'm getting ready to go for a drive and wondering how warm of a jacket to wear. I absolutely love Hawaii, we rent a house every year for a couple of weeks, usually in Maui.

My new Mountaineer has the digital temp control and the temp goes down to 60 deg. I assume to get a large vehicle to an internal temp of 60 on a hot day that the outlet temps should be lower than 60 and lower than 58. Tell them it is unacceptable and have them check the factory install - could have a small leak at an o-ring. My 98 Subaru had a factory a/c leak.

[Jack Olsen]

That's pretty outrageous, for a modern car. Whatever their 'spec' is, I'd think you'd get an easy resolution for this by moving further up the service hierarchy.

My 911's AC (with a few mods) puts out 37 degree air on an ambient 85 degree day.

[stlrj]

Most a/c technicians like to see a 30* drop at the vent as compared to inside cabin temp.

Jose

86 Carrera

[radcon]

Thanks for the feedback guys. I was thinking that the temperature differential between outside temp and vent outlet temp should be around 40 degrees at least. For the A/C system of a modern car to only be able to cool down the air by 25 degrees or so sounds ridiculous. Particularly when the A/C systems in every old piece of crap I've owned could freeze me out.

[stormcrow]

Your system temp should be at 40 F regardless of what the outside temp is if it is a newer vehicle. Sounds to me like it is low on refrigerant.

Take it back and have them check the charge. Sounds like they took advantage of the situation because it was a woman who was asking the question. Ask them to put the gauges on and check the superheat on the system to determine if it's low. Also ask them to check the sight glass to see if it's clear (no bubbles). If you see bubbles, then it's low on refrigerant.

Steve

[Jadams1]

I get 48 F on a 95 degree day with mine running R-12.

[jmohn]

Any well functioning automobile AC system should be putting out about 42-46 degree air at the center-most vent with control on full cold and the fan on a medium speed setting. The newer AC systems (using 134a) are very sensitive to the amount of "charge" in the system. Assuming the system is intact and functioning properly (they should check that the heater valve is closing properly and not mixing in heated air), your system could be either slightly over or undercharged. The correct way to "fine tune" these systems is by reading the air temperature at the vent and adjusting the amount of charge to reach optimum cooling. In a modern car 58 degrees is not acceptable, heck it wasn't acceptable 30 years ago.

Jerry M
'78 SC (48 degrees at the vents at 90 degrees ambient)