Write-Up: HVAC Assembly

LOVE the color of your car!  PLEASE tell me that it has a nice red interior instead of my "Medium Neutral" interior...

98RivOwner wrote:

Yes, plastic hub gear cracked per picture in my post on 9-1-23 @3:10pm

Sorry Eldo, its the beige neutral color.
I actually don't mind the beige, Im not that picky with colors.

Thanks for the comment

My car needs a paint job soon.

Better than grey.

The problem today is unless you buy a Rolls or something else expensively bespoke, you can't get any interior colors EXCEPT beige, black or brown...  My God, in the 70's you could even buy a Nova or Pinto with matching or contrasting interior to go with the paint, not to mention that even THOSE cars could be had with a matching/contrasting VINYL TOP!

Eldo wrote:

The problem today is unless you buy a Rolls or something else expensively bespoke, you can't get any interior colors EXCEPT beige, black or brown...  My God, in the 70's you could even buy a Nova or Pinto with matching or contrasting interior to go with the paint, not to mention that even THOSE cars could be had with a matching/contrasting VINYL TOP!

freedom of choice is what we want, freedom from choice is what we got...

It's been many years since his post, but I want to thank Tajis for his confirmation that - once aGAIN - the FSM is mistaken...  It will definitely be easier to get to the middle motor for my blend-air problem than the 'front one'.

Tajis wrote:

Success! I now have air coming through my middle vents!

For the number 2 motor, get a thumbwheel ratchet and feel for the bolts. Attach the ratchet and twist the bolts off. Keep in mind you're basically doing this blind due to the vent being in the way. This is the motor that mixes hot and cold for the driver's side.

Number 3... That's the one that is a PITA to remove. The bolt furthest away from the driver's seat on the number 3 motor is easy to remove. The thumbwheel ratchet will fit right on and have it off in no time. The one closest to the driver's seat is hard to remove. Remove the hard to reach bolt first, since if you don't the whole actuator will be wobbling and trying to get in the way.

I ended up getting a six inch long, quarter inch wobble socket extension. You cannot do this without a wobble socket. This let me flex the 7/32 connector down onto the bolt (with several tries). You will have to run the extension through the open middle of the nearby support arm thing. The socket will not get an easy grip, but it WILL come loose with enough persistence. I ended up holding part of the extension down so that the socket remained angled correctly.

Also, if you have a helper it helps if they hold a flashlight toward the main set of vents over the shift stick. It's the easiest way to get a light on where you're aiming.

Once this is off you'll be able to either replace the part or otherwise manually route the air back up to the vents!

I hope this helps someone not have to go through the trial and error process like I did.

Thank you a LOT Doc!  

It's just criminal how many mistakes are in this one section of the Factory Service Manuals!  
The paper manual has insanely brief instructions generalized for all FIVE actuators, while my GM electronic service information FSM has more distinct instructions BUT fewer diagrams than the paper one, and mislabels the Driver's #3 motor as the blend-air door instead of the floor/dash diverter...  #2 makes more sense both from the extra diagrams in the paper manual as well as the relative position of the passenger blend-air on the other side.  Plus, the eSI manual says you have to pull the entire entire freakin' dashboard carrier back from the firewall!  
As far as the Console, that's child's play compared to the other things they want us to remove...  Yes, all those top screw-holes are insanely breakable, but hell, the whole thing just sits inside of the outer unit and I've always been lucky with the ashtray/CD unit clips.  

[Besides, if it makes it easy to remove the DS ducts and replace all 3 motors in one operation, this would also be a good time to replace the aluminum heater core... though that does require a remote, cable-operated hose-clamp plier.]

Speaking of paltry instructions, can you tell us how to disengage that "internal clip" in the driver's upper duct?  

EyeDoc1 wrote:

OK...actually 48 hours went by and happy to say that I was able to get the ductwork back together WITHOUT resorting to removing the console.  Having broken off one plastic tab on the ductwork actually made it easier to re-install, as I only had to push down on the slot on the upper part of the pre-existing ductwork to slide the tab into place and then push up on everything to seat the clip.  Took about six minutes of laboriously working my hands around a very tight spot, but it can be done.  I recommend putting the seatback all the way down, get an old pillow for your head or take 3 ibuprofen from the back-neck strain you're gonna be feeling later.  Once you get the piece of ductwork back into place, you can then install the other piece of ductwork that's about a foot long and one side has that corrugated rectangular shape and that's a breeze compared to the other.

In fact, avoid taking the console apart at all costs, as I sure as heck broke the plastic tabs that hold the ashtray in, so that another junkyard piece I'll need to get...down the road.

Looks like the weekend will be made for a intake manifold gasket replacement on the firewall side.  Always something.

Christen

98RivOwner wrote:

Also, I noticed my Riviera does NOT cool as well as I remember it cooling, but I haven't used the A/C in a long time, but the last time I did it would run you out of the cabin, not as cool today...I will see about a refrigerant performance check.

Hello again.  Besides asking you how to disengage that "internal clip" in the driver's upper duct - after pulling the console & center registers - I just recalled something that I wanted to remind you of.  

When comparing the outlet temperature of your A/C at different times, you have to remember that our cars use the V5 compressor with variable piston stroke instead of cycling the clutch on & off.  This is great for no cutting in & out at stop lights, virtually no power & fuel penalties in the winter for defogging or on mild cooling days, and essentially infinite clutch life.  
However, there is one tradeoff: unlike the cycling-clutch compressor that is controlled by the electronics, the piston-stroke is controlled internally by the pressure in the return line, which varies based on how hot the incoming air is...  Thus, it can freeze you out of the car driving down I-24 at 99°, but if it's only 75° outside and the car has been parked in the sun, you can't get the same ice-cube outlet temps.

Well, now that the latest problem has been conquered, I wanted to share another bit of ECC/HVAC info with y'all...

After I tried squeezing down there and feeling the center motor, just the torque of my hand caused a tab somewhere in the duct that feeds the floor to break.   After that, the duct dropped an inch or two and the middle actuator was actually accessible.  With a 1/4-inch "screwdriver-handle" and about 6 or 8 inches of wobble extension, my slim buddy with a non-arthritic spine was able to master the removal of the 'middle' driver-side actuator (the blend-air door that is sometimes mislabeled) by just reclining the seat-back all the way and tilting the front of the seat all the way down - and putting a towel & pillow on the floorboard...  In fact, because of the second thing I must share, he became so proficient that he could swap one out in 5 minutes!    

The reason we changed it 3 or 4 times is that I had bought 2 different brands of actuators, which proved to be identical regardless of one being a no-name $25 unit and the other a $50 Four Seasons one...  BTW, there have been at least 3 different outer shells for these motors, the originals having actual screws, and both of these had the thin latch-tabs where one of them breaks the first time you try to open it up.  However, the big "BUT" is that contrary to almost everything you read on the web - and the fact that the manuals are written for Tech II owners - pulling fuses or even pulling the plug from the Programmer under the RH side of the dash, as I did, did not make the actuators find their correct position on the first try, or even the 2nd or 3rd!

Unlike the bad actuator, the new ones did move whenever the temp was changed, but the driver's side stubbornly remained warmer than the passenger side...  Sooooo, we then tried the other new motor, which yielded the same result. Then I opened up the 1st one & manually moved the gear a few teeth toward Cold.  The results were the same, the computer was still setting it too warm.  We eventually put the first one back in, had the same result, and shut it down.  After about 15 minutes we started it again and still had imbalanced temps.  While topping up all our tires we burned another 20 minutes and started it up again. This time we both thought that the driver's air was a little colder.  After he went home and I cleaned up the garage, I started the car to put it back inside.  By the time I parked, I realized that I was actually getting cold air on the driver's side!  

So, even thought cutting the power definitely triggers the 'learning' mode (Auto, 75 degrees & Passenger Control lit up,) it takes several separate ignition cycles afterward for the thing to actually decide where the ends of its travel are...   Now my problem is that despite a gauge that refused to move higher as I added Suva, I think I've overcharged it and it's not as cold now!