Sometime last week I set out on a mission to make my AC blow colder (I have a 2003 Sport XLS with the 3.5L). The AC has always blown cool, but never cold enough to make me comfortable on a hot day.

So I got a loaner set of guages and a vacuum pump from Autozone. Pressures were actually normal. Because (from what I understand) the US models never came with cabin air filters, I suspected that the evaporator fins may have gotten gunked up and perhaps that was causing the less-than-ideal temps. In fact, last year - not long after I got the car - I installed a cabin air filter (had to actually cut into the cooling unit to install). I remember taking a skinny vacuum attachment and sucking out what I could of the crap that was in there, but couldn't get to all of it. Now, a year later, I wanted to do a better job cleaning in there.

Well, long story short, I got the system discharged so I could pull the entire cooling unit out. Plus, I had noticed frothy bubbles in the sight glass of the receiver drier. If there was air or moisture in the system, I wanted to get that out anyway. Turns out, the evaporator wasn't even that dirty. A quick blow off with an air hose and it looked good as new.

For good measure, I put in a new expansion valve (I doubt there was anything wrong with the old one, but I was fooling around with it to see how it works and ending up taking the set screw and spring out. It didn't occur to me that I now had no idea how far to screw the set screw back in to set it to the correct pressure, so I just bought a new one) and I put in a new receiver drier as well.

Before I put everything back together to pull a vacuum, I noticed something:

I had the **** for the air mix turned all the way to cold but the damper that closes off the heater core wasn't closed all the way. I guess, over the years of moving it back and forth, the throttle cable coming off the **** started sliding forwards in the clip, keeping it from fully closing the damper. I thought perhaps this was the real reason my AC wasn't blowing as cold as I'd like (though it wouldn't account for the bubbles in the sight glass).

So, I fixed the cable, installed the new TXV and receiver drier, pulled a vacuum on the system, made sure it held said vacuum, then recharged it, making sure to add some PAG oil to make up for what I had lost (note: here is one of my mistakes. A nice mechanic discharged my system for free, even brought me over to the machine to show me how much oil came out. I completely forgot to make a note of how much oil came out! So there was some guesswork involved when I put oil back in. 70ml for the evaporator, because I blew out all the old oil in it for good measure. I just poured it right in the suction line before reassembly. Then I added 20ml while recharging, 10 for the R/D, and 10 for the suction line, as stated by the manual. I hope this is close to matching how much came out during evacuation, but I don't know for sure).

Finally, the system was recharged. Put in 24oz of R-134a, which is what is printed on the hood. Pressures were good. Felt confident the AC would be ice cold. Aaaannnddd...

Nope. It may have gotten a little colder (probably thanks to the damper fix) but it's still not comfortable enough for me. What is interesting though, is that according to the service manual, the temps I'm getting are actually normal. Here's the chart they give:


It was about 75 F while testing, full cold, recirc on, and I was getting around 42-46 coming out of the center vent, same temps coming right off the evaporator. According to this chart, that's right about where they should be. But I took it on a drive for about 30 minutes or so and I just never felt comfortable, even though temps stayed around 42-46. Out of curiosity, I tested my mom's suburban (which I know gets plenty cold even in the heat of summer) and it's around 42 coming out the vent!!!
What!!!??? How come my car feels so much hotter in the cab despite the discharge temps being so similar?

There must be something I'm missing. What are your guys' AC temps like? Does it actually feel cold enough in the heat of the summer?