PontiacBonnevilleClub.com

Update to old thread:
http://www.pontiacbonnevilleclub.com/fo ... t=actuator

Cliff's notes:
-Driver's side A/C warmer than passenger's side (dual control)
-Actuator suspected, but seemed OK from external examination
-System pressure (low side, anyway) OK

After putting it off a year, I finally got around to tearing out the entire dash (surprisingly easy, BTW) to visually see what the hell's going on with the blend doors, etc.:


All the blend doors worked flawlessly. All the little temperature sensors in the ductwork measured the same ohms, and changed the same when put in the freezer. I literally could not find a thing wrong mechanically or electrically. Yet the driver's side A/C is still warmer than the passenger's side.

What to look at next? Should I take to a shop for a full pressure test (low side AND high side)?

You could try the cheap route first, and add a can of refrigerant. I did that last year, and though it didn't significantly raise the low side pressure, it did make a difference in the cooling.

I had the same issue just recently. I looked at everything and could not find a problem. So, I bought a can of refrigerant and dumped the whole thing into the system and haven't had a problem since.

Give it a try. Beware though and don't try adding anything if the system pressure is to high. Low pressure should be around 40-44psi.

Norm

Granted it was last summer when I last checked, but I tried a can of refrigerant then and low-side pressure was already at 40psi.

I'll see if I can dig up the old can-topper gauge and check it again.

I posted in another thread somewhere....Harbor Freight has a decent AC gauge set and it's not that expensive. http://www.harborfreight.com/cpi/ctaf/d ... mber=92649 Having the right tools can make a world of difference.

"Let's be careful out there" -- Phil Esterhouse

What I'm about to write may also apply to anyone who comes across this thread:
http://www.pontiacbonnevilleclub.com/fo ... t=actuator

So anyway thanks to HurstGN's suggestion--and a 20% off at Harbor Freight coupon I found on this site--I picked myself up the AC manifold gauge set over the weekend.
Sunday night: checked the 2004's pressures: 30psi low side / 100 psi high side...definitely low.

(Just to check my measurement technique, I checked the 1998's pressures: 45 psi / 200 psi, right smack-dab OK in the very middle of the FSM's diagram of AC pressures)

Sent the wife out to the auto parts store for a 14oz can of direct-charge R134a/PAG (about $17). Filled it in the low-pressure side while watching the high-side gauge. Pushed up to 225 or so psi almost immediately--then within seconds starting dropping...dropping; within 30 seconds high-pressure side was back down to 100 psi. Definitely a bad leak somewhere.

(On the good side, it still would hold some pressure...)

While she was in the driver's seat, she reported that the AC vent blew cold while the pressure was briefly high...and that she smelled a definite "chemically"/"anti-freezy" smell (probably PAG oil) while the pressure dropped off/freon leaked. Combine that with the fact that I could find no oily traces at any other potential leak points (hoses, lines, ports, connections, condenser, compressor), and I'm 99% sure the leak is somewhere in the evaporator.

Well, now I knew where the leak was, I didn't feel the need for a dye kit or to borrow a freon sniffer. I was either going to seal this baby with some magic-in-a-can, or get ready to rip the whole f**kin' system out.

So after a lot of net-research into sealers, last night (Tuesday) I ran down to the auto parts store and got Interdynamics Super Seal MRL-3 (cost about $23):
http://www.interdynamics-europe.co.uk/r ... .php?id=59


(Note that this is available in the US now, though not yet on their US site)

I got this for two reasons:
1) It is the only easily-available DIY product I could find that has sealers for both rubber (hoses, o-rings) and metal (lines, condenser, evaporator) in a single can.
2) It came with the can-tapper service port hose (would have been $13 alone) that allows me to use the cheap $8 cans of freon.

Apparently it seals metal by circulating some sort of moisture-cure epoxy that fills gaps at leak points where condensation occurs. Sounds good to me.

So I warmed up the car with AC on full, shot the Super Seal in, followed immediately by an 11-oz can of plain R134a, and let run for 15 minutes to circulate (as per directions). Pressures now at 45 psi / 200 psi, with both driver's and passenger's AC vents at ~52°F

I shut 'er down, let it sit for 2 hours, and ran it again--pressures still at 45 / 200.

Tested it again this morning, still holding at 45 / 200.

We'll see how long that holds up!

I'll keep my fingers crossed, and hope that it holds.