Write-Up: HVAC Assembly

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.  Have 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

Thanks for the info. I had a similar problem a month or so ago with my AC. My AC also needed to be charged. Weird how it will still blow cold on the passenger side and not the drivers with a low charge.

I had taken out the center console this winter to fix the cracked wood around the shifter and I also encountered the same broken clips on the ash tray. It's a bad design as the plastic isn't thick enough to be pulled on. It also doesn't help that my car is almost 20 years old. I just put some hot glue on the back of the pieces to keep it from rattling, so I didn't need to buy another one. I don't use the ash tray anyway. I also had to fix a couple of cracked plastic pieces in the center console with some epoxy, fiberglass tape and some nails for added strength.

Putting in a new actuator cant line up the shaft in the hvac  with the new part it  does not turn it is set all the way to 1 side should a new one
be in the middle position thx for help steve

Inside the actuator is a synchronous motor (moves exactly some distance given certain voltage input over certain time, think analog clock) and some gears.

What worked for me: I opened the actuator (look at it real hard, you'll figure out how the case unsnaps) and reposition the gears so you can install it.  When you get things back together, cycle the HVAC (not too quickly)  through all the air flow and temperature settings to allow the actuators to correctly reposition.   Nervous about this? I don't blame you -- just open a *broken* one first, to see how it all goes together.

Thanks Albertj  I took it apart all u have to do is lift the gear up and it disconnects motor and I put it in the middle.I had all 3 bad on drivers side OUCH

The actuator you pictured has a broken gear around the large black plastic hub.  It will *probably* work once assembled as-is but only until the gear breaks someplace else, which it will pretty soon.  I had an actuator I "repaired" but did not have an extra large gear like that so I put it back together with a gear that looked pretty much like what you have pictured.  It worked for a while, I am thinking 5 months, but I had to repair it again because it finally failed, the big gear split and came off the hub.  

OK, so here's the cool thing -- GM's got great engineering but not so much variation when it comes to hard parts like this.   If you get any of their similar HVAC actuators and open them you will find similar - most likely identical - gears inside.  

At a pick-and-pull, either at the entrance desk or customer service or what have you they will usually look up the cars for you that have the same or similar actuators you can pull from.  A bunch of cars match up to one or another of the Riv actuators.  So... you let them give you the list and hopefully the places those cars are in the lot and you just pull the actuators off the ones that are not too hard to get to.  They are so cheap at the yards you can pull several and you'll most likely get the parts you need, and now that you know how to open them you can pop them apart in the yard and check...

The other thing you can do is get *just about any* of the older (mid 80's-mid '90s) GM actuators, the older ones had metal gears and those metal gears never really did break. You can swap many of the metal gears into your actuators with good motors/bad gears and wha-la, you have ready-to-use repaired actuators. It will take some guesswork to find the cars that have actuators with metal gears.  Thinking about it, I wonder if I pulled actuators off cars older than what's listed on the Hollander.  I don't recall.  Also it occurs to me that someone with the right skills and equipment could *3D print* those gears.

Thx for the tips

71stagegs wrote:

Thx for the tips

You're welcome. I found working on the HVAC to be a bit much and don't mind sharing what I learned. Sitting on my head under the dash was fun for my spouse to watch and not fun at all to do. And those controllers... once you take a good look inside, they are not tough to fix.

LOL I took the seat out takes 10 minutes when u lay down you can get your head in there still a nightmare

I got heat! put all 3 in today all the air flow directions work #3 in pic is rough the front bolt is a nightmare u need a universal and long extension to get it out then trying to start it is crazy I took it back out and put some clay around bolt and reinstalled it and the bolt stayed there then u have to get the universal going to get it started but at lease its in position.I took my seat out only way I could get in there.Rock Auto had Delco's for $75 I'm going to do r/s next I'm sure they are cracked too. those r over a $100

71stagegs wrote:

I got heat! put all 3 in today all the air flow directions work #3 in pic is rough  the front  bolt is a nightmare u need a universal and long extension to get it out then trying to start it is crazy I took it back out and put some clay around bolt and reinstalled it and the bolt stayed there then u have to get the universal going to get it started but at lease its in position.I took my seat out only way I could get in there.Rock Auto had Delco's for $75 I'm going to do r/s next I'm sure they are cracked too. those r over a $100

...again, I've had good luck with junkyard pulls.

I suspect the ones with plastic gears had already been replaced in the donor cars, and so were not that old.

VegasScott wrote:

99Rivman wrote:

This is the vent part that someone had removed!

Anybody know how to remove that piece he is refering too?  

My console is still in the car, and I don't want to take it out if I don't have to.

Thanks,
VegasScott

How do you get this duct out?

I've had a problem with my HVAC system for awhile. With temperature set to minimum (60*), the air on the driver's side and center vents is noticeably warmer than the air coming out of the 4 passenger side IP vents. It isn't warm or even hot, just warmer than what comes out of the 4 passenger side (round ) vents. The passenger side vents are nice and cold, it's just the driver's side. That has to be one of the 3 actuators on the driver's side I'd think. Anyone know which one? Also, I have the same question as VegasScott and TampaRivGuy in the post above this one, how do you get the vent piece (pictured) out? Does it pull out? It blocks access to the actuators.

All I can remember about that vent is that I broke a tab pulling mine, but when I had it out I figured out how to do it without breaking anything. But that was so long ago, I remember nothing more. I've noticed no ill effects from the broken tab though.

LARRY70GS wrote:

I've had a problem with my HVAC system for awhile.  With temperature set to minimum (60*), the air on the driver's side and center vents is noticeably warmer than the air coming out of the 4 passenger side IP vents.  It isn't warm or even hot, just warmer than what comes out of the 4 passenger side (round ) vents.  The passenger side vents are nice and cold, it's just the driver's side.  That has to be one of the 3 actuators on the driver's side I'd think.  Anyone know which one?  Also, I have the same question as VegasScott and TampaRivGuy in the post above this one, how do you get the vent piece (pictured) out?  Does it pull out?  It blocks access to the actuators.

Double check the setting of the passenger temp control on the passenger door.

The big gear in the drivers side blend door actuator is probably wack.

What worked for me was to pull the actuators, it's not that bad once you get to the first ones, and open them and check the gears. You can overhaul them with junkyard parts *or* Dorman now packages gear kits for rebuilding the actuators *or* just do a search on eBay or Amazon and replacement gears will appear.

I don't remember how to get that vent piece out but there was something in the factory service manual. I don't remember having to get the vent piece out to work on the actuators.

Thanks Albert, I have some 4 season actuators I bought from Rock Auto. I took a look at the area and it looks like that vent piece kind of blocks the whole area where the actuators are. I'll see if I can get it out. My friend Steve (71stagegs) told be that it snaps out but you have to depress a button or something. If I figure it out, I'll post how.

LARRY70GS wrote:

Thanks Albert, I have some 4 season actuators I bought from Rock Auto.  I took a look at the area and it looks like that vent piece kind of blocks the whole area where the actuators are.  I'll see if I can get it out.  My friend Steve (71stagegs) told be that it snaps out but you have to depress a button or something.  If I figure it out, I'll post how.

Ha!  I guess the reason I don't remember having to get the vent piece out to work on the actuators is that it hurt so much and I chose to forget!  Must have snapped out.

In hindsight, putting those metal gears into the actuators that I got from the junkyard pieces was clever ehough -- I have not had to work on the HVAC since doing those swaps several years ago.

98riv wrote:

I was looking at gmpartsdirect.com and was looking at the parts diagram for the hvac and it lists a filter for the hvac system.  Part number 6 is the filter and part 7 is the filter retainer.  http://www.trademotion.com/parts/1998/BUICK/RIVIERA/?siteid=214858&vehicleid=1303322&diagram=AD95066 I always heard that we didn't have an HVAC filter on our system.  Is that a different filter than what I am thinking of?

https://www.ebay.com/p/gm-oem-cabin-air-filter-52472209/658905886?iid=322513575960

albertj wrote:

98riv wrote:

I was looking at gmpartsdirect.com and was looking at the parts diagram for the hvac and it lists a filter for the hvac system.  Part number 6 is the filter and part 7 is the filter retainer.  http://www.trademotion.com/parts/1998/BUICK/RIVIERA/?siteid=214858&vehicleid=1303322&diagram=AD95066 I always heard that we didn't have an HVAC filter on our system.  Is that a different filter than what I am thinking of?

https://www.ebay.com/p/gm-oem-cabin-air-filter-52472209/658905886?iid=322513575960

Looks like typical cut to fit home A/C filter material. That's a huge rip off, you can get a much bigger piece at Home Depot and just cut it to fit.

LARRY70GS wrote:

albertj wrote:

98riv wrote:

I was looking at gmpartsdirect.com and was looking at the parts diagram for the hvac and it lists a filter for the hvac system.  Part number 6 is the filter and part 7 is the filter retainer.  http://www.trademotion.com/parts/1998/BUICK/RIVIERA/?siteid=214858&vehicleid=1303322&diagram=AD95066 I always heard that we didn't have an HVAC filter on our system.  Is that a different filter than what I am thinking of?

https://www.ebay.com/p/gm-oem-cabin-air-filter-52472209/658905886?iid=322513575960

Looks like typical cut to fit home A/C filter material.  That's a huge rip off, you can get a much bigger piece at Home Depot and just cut it to fit.

Yes, I'd be careful that it was not made of a unique polymer but odds are it is standard HVAC permanent filter material.

It's interesting that the subject of cabin air filters just came up because I was on another forum earlier for GM pick ups and some pre-2003 vehicles came with them from the factory but they are burird deep in the passenger side just before the evaporator.
Then GM stopped installing them until something like 2013 models.
But  guy did a write up with pic that showed the plenum on a non-filter equipped year and it had
molding/casting marks in the same place that the filters would be installed.
So he took a dremel to that area and carefully cut the same section out, just before the evaporator
and found a retrofit kit from Dorman that fit perfectly and had the piece to cover what needed to be cut out as part of the kit.
For more money you can get the individual pieces from GM as someone posted the part numbers but no pic's. But the Dorman product fit like it belonged there and even the cover plate had insulation to seal the plenum back up.

If my back wasn't so screwed up I'd be ordering the dorman kit with charcoal filter for around $40.00 shipped, maybe a bit mor but less than $50.00 from what i remember.

For you allergy sufferers you may want to have a look at the HVAC box and see if there are molding impressions just before the evaporator and cut it open to install a charcoal filter from GM and then make a cover that can be removed and re-installed.

Rickw wrote:

It's interesting that the subject of cabin air filters just came up because I was on another forum earlier for GM pick ups and some pre-2003 vehicles came with them from the factory but they are burird deep in the passenger side just before the evaporator.
Then GM stopped installing them until something like 2013 models.
But  guy did a write up with pic that showed the plenum on a non-filter equipped year and it had
molding/casting marks in the same place that the filters would be installed.
So he took a dremel to that area and carefully cut the same section out, just before the evaporator
and found a retrofit kit from Dorman that fit perfectly and had the piece to cover what needed to be cut out as part of the kit.
For more money you can get the individual pieces from GM as someone posted the part numbers but no pic's. But the Dorman product fit like it belonged there and even the cover plate had insulation to seal the plenum back up.

If my back wasn't so screwed up I'd be ordering the dorman kit with charcoal filter for around $40.00 shipped, maybe a bit mor but less than $50.00 from what i remember.

For you allergy sufferers you may want to have a look at the HVAC box and see if there are molding impressions just before the evaporator and cut it open to install a charcoal filter from GM and then make a cover that can be removed and re-installed.

so... you could actually install a door in the Riv to get to that filter? Hmmm.....

I'll try and post a link to that thread on the other forum. Everyone says its a pain in the back to gain access to it and then lay under the passenger side of the dash while you cut the rectangular opening.
There was also a mention of the crap that falls out of that area once you remove the plastic piece you just cut off. Apparently there is quite a bit of different things that get caught in inlet side of the Evap Coils when you don't have a filter. Over time it affects the efficiency of the evaporator as well as being a reason for the moisture drain to get clogged up.
The bacteria that is present after years of moisture in that area should be treated with something also.

I could use some help on my actuator install (yesterday).

I replaced all 3 drivers-side actuators, now I have this THUMP when changing the air blend.  Is there  a trick to setting the actuator in place on the flap axles?  Should I re-run calibration?  Not sure what to do.  Please advise.

Albertj

By re-run calibration, do you mean you already did it? it wouldn't hurt to try again. Are you sure you have the right instructions for the calibration procedure?

I don't remember there being any special tricks to installing the modules. I don't have one on hand, doesn't the output shaft have a half-moon design so it only goes on one way?

Surely you couldn't have flipped the actuator door over?