What should the A/C temperature be at vents?

[m3f_smithk3933]

A/C doesn't seem to cool as well as it once did. I measured the temperature at the center vent with it set on max cool and re circulation. The temperature measured 62 degrees. By contrast, my 2012 MDX measures 46 degrees.



What is normal temperature at full charge? I checked my Bentley but couldn't find a spec.



Thanks.



Keith

[m3f_MMMGP]

Good question, I'm in for responses.


What did you use to measure the temp at the vent? Had the car been sitting outside on a warm day causing the interior/plastics around the measurement area to warm up? How long did you run the AC before measuring?

[m3f_smithk3933]

Car had been in garage and allowed to run for 10 minutes until temperature stabilized.

[m3f_white-hot]

When I first got the coupe the AC system had been opened to atmosphere for several months, so had to get it all back together with a new dryer. After reassembly, vacuum and recharge it was kicking some serious ass. The tech used an infrared temp gauge to check a few places, and the back of the center vent showed 42 at one point and stayed in the 40's for half an hour during testing. I would suggest if you are running 62 then it may be time for a service where a vacuum is pulled and then it gets a recharge. I would also get them to put some dye in with the refrigerant to see if you have any leaks in the system. If the system has never been apart it might just be as simple as topping it off, but I would get a vacuum pulled anyway.

[m3f_enderw88]

I get in the low forties as well.


Make sure that your aux fan is working. That is the only thing driving flow over the condenser if the car is stopped.

[m3f_dkegel]

I have been told mid to low 40s.



Dave

[m3f_Dano98m3]

I read somewhere that is around 40 degs lower then the ambient outside temperature. I did mine with a laser thermo when it was around 80 outside and the center vent was in the low 40s. The other day it was 108 outside on the highway and the air coming out didn't feel nearly that cold 60?ish

[m3f_enderw88]

I read somewhere that is around 40 degs lower then the ambient outside temperature. I did mine with a laser thermo when it was around 80 outside and the center vent was in the low 40s. The other day it was 108 outside on the highway and the air coming out didn't feel nearly that cold 60?ish

It can take a long time to cool down the ducting in the interior. If the car sat in a parking lot heating up, it can take 15-20 minutes before it has cooled the interior down (I live in Tucson, I get to experiment with this frequently) Then the outlet temp will be in the forties, and can hold its on against up to 112 degrees in my experience.

[m3f_Coop920]

I recently had my whole ac system changed and the guy ran the infared thermometer on my main vent and was getting 42 degrees. Granted, this is when my compressor is working (i believe my compressor is a dud from the parts supplier).

[m3f_dkegel]

I read somewhere that is around 40 degs lower then the ambient outside temperature. I did mine with a laser thermo when it was around 80 outside and the center vent was in the low 40s. The other day it was 108 outside on the highway and the air coming out didn't feel nearly that cold 60?ish

I don't think that is correct. That would mean 30 degrees when it's 70 out. It would never be that cold. Also, it should be in the 40s even if it's 100 out. The car would take forever to cool off if it were only 60 degrees coming out the vents.



Dave

[m3f_ed007]

I consistently measure 42 - 45 with the infrared thermometer at the center vent regardless of the outside temperature.