A/C charging issue resolved.

[Ed Lijewski]

You know, my friend, I have a doubt that your vent flaps are not marginally inhibiting air flow. Years ago I raided 2 or more JY Scorpios for various parts including vent motors, flaps? And even the behind dash vent housings. And I own two Scorpios. Almost all vent flaps were torqued (twisted) at least slightly or more.

I've posted before that the Scorpio's vents position is a compromise that is fine for HVAC 9 months of the year but when a/c is really needed the center dash position reduces passenger sense of humidity reduction and cooling. There is no esthetically correct fix for that, although adjusting vent blades to direct air upwards makes a difference.

I get good cooling effect by: setting temperature to 00, setting air flow to only Center vents (footwells will still benefit from cool center air falling towards them), adjusting vent blades to direct air to driver-passenger, setting fan speed to Low while idling then to Medium when underway.

I have window sun shades on each inside door window. I have a near full sun shade on the inside hatch window. I have reflective sun shade lain on the trunk shelf to deflect rays back to the glass. I have a 3" plastic film sunscreen at the top of the inside windshield.

I never park in full sun. Ever. Anywhere.

And I've never run R134 refrigerant because it doesn't cool well in stock Merkur systems.

Would rear seat passengers be comfy cool.in my Scorpio? Underway, yes. Stuck in traffic, may not so much.

YMMV

[brokencase]

Sure, we can all agree that parking in the shade is mandatory with the Scorpio. But often one does not have a choice in this matter.
It is under these circumstances that the inadequacy of the a/c system is revealed.

On my original Scorpio I had some pretty dark (75%?) tint on the side and rear windows. This helped but was problematic because cops would pull me over and give me warnings. For some reason I think that today cops would not care because I have seen a lot of vehicle's around with pretty dark tint.

On my current Scorpio I installed 15% tint, but it is special "IR blocking" tint. I tested the IR blocking capability of the film before I installed it by placing it between a large halogen lamp and my hand. It really does block the radiant IR. However in the real world the Sun has strong output in all wavelengths, so I don't feel that this works as well as the really dark tint did.

My neighbor has a late model Buick Sportswagon. I can't remember the model, but it is actually a re-branded European Opal. This vehicle has the same issues as the Scorpio, dark leather interior, lots of window glass, etc. Anyway, from Europe he bought these really neat custom fit side window shades.

They have a really thin and narrow metal frame that is stretched over with this finely perforated shade material. The frame is sized to the vehicles window openings and fits into the inside of the frame of the window via little spikes that bite into the fuzzy track around the window. You can see through them perfectly from the inside and you can leave them in permanently. Windows can still go up and down.

I sure would like to make a set of these for the Scorpio, including one for the rear hatch glass. I don't like the idea of applying window tint over the defrost grid.

Anyway, shade/tint issues aside...

This morning I was looking at RockAuto and checking out blower motors across various vehicles over the years. The Scorpio blower motor was the same as used on certain BMW models in the 80's and 90's. However in most cases the squirrel cage fans fitted to the BMW's are much larger than those fitted to the Scorpio. Makes me wonder if they ran into a size constraint when designing the air box for the Sierra series of vehicles.

As you move forward in time it looks like most manufacturers migrated to a single and much larger squirrel cage fan. I suspect that the flow probably increases with the square of the diameter. So that single large fan can move much more air than the small dual fans and it probably does not have to spin as fast. Not to mention when you have two small fans you have "doubled up" inlet and outlet turbulent losses.

When you turn the Scorpio fan to high it is noisy as all heck. That rushing noise is turbulent flow. It is not smooth flow. That turbulence is at the fans or through the duct work and vents. Conceivably, if you could reduce the turbulence you would increase flow and reduce the noise.

Finally, Ed, I don't notice any difference in the cooling capacity between R12 and R134a. I took the car out this evening to the Burger joint about 3 miles away. On the way back I was seeing about 37 degrees at the vents. It was about 80F ambient. The seats were still warm from sitting in the sun prior to the drive so I suspect the vent temp would have dropper further had I continued to drive longer. On my old Scorpio I had run both types of refrigerant and noticed no difference as well.

[brokencase]

Ed, Here are the same type of side window shades my neighbor installed on his Buick.
https://quiksnap.us/

I was thinking about purchasing some material like this to make my own shades for the Scorpio.
https://www.ebay.com/itm/182007075075

Just need to locate some thin stainless steel strips that I can tack weld to make the frames.

[Ed Lijewski]

Thanks.

I'd buy a set...if I could get the website to work; the "If I can't find my car" hotline didn't work (for me).

YMMV

Re: https://www.ebay.com/itm/182007075075

I have a very large roll of that kind of mesh which fell off a truck on a nearby road several years ago. Been using small sections of it for odd uses-covering the leaf collector e.g.-but there's ~90% left. You're welcome to as much as you need, just pay postage.

YMMV

[brokencase]

As far as I can tell nobody makes a shade set like that for the Scorpio.

If I could find a source for the metal strip to make the frames I don't think it would be too hard to make a set. I reckon 0.30-.040" thick by 1/4" stainless would do it. The fabric is inexpensive.

[brokencase]

BTW, Tomorrow I'm going to take my borescope camera and inspect inside the dash vents and maybe see if there is any crude obstructing the intake side of the evaporator core fins.

[Ed Lijewski]

Some debris there is always a possibility.

Would love to see verification photos of your Unicorn still-in-fine-shape three vent doors.

YMMV

[brokencase]

Looks like the center vent door is OK.

The USB camera is a bit low res. A little hard to make out things.

The foam seal is intact and I don't see any evidence of the "torque twisting" you indicated earlier. Keep in mind Ed, my Scorpio is around 87K and a well cared for Oregon car.

The driver's side door appears to be closed so it was difficult to discern things. But I know it opens because I get flow out of it when the A/C is on.

I'm looking at the Helm's manual now to see how to remove the deflectors. I'd like to observe then vent doors in action while adjusting the EATC.

Center, left side

center_Left.jpg

Center right side

center_right.jpg

Is that "Unicorn Pristine" enough for you?

[brokencase]

The manual is not clear in section 45-61.

I understand how to remove the vent deflector on the driver's side. I removed that one before (out of curiosity) when I installed remote door lock unit under the driver's side lower dash panel

How do you remove the wooden surround on the center/right side of the dash?

[Ed Lijewski]

Center panel unclips easily with a thin screwdriver prying at 2-3 points.

YMMV

[brokencase]

OK figured it out. You just gently pry the panel and vents out.

So... Vent doors are in good shape.

..and now I see what you mean regarding the poor design of the vent doors. They are not very streamlined in the open position.

However when I cycle def/panel/floor on EATC I notice that there is no movement of the driver's side vent door.

It is stuck in a half way position, so I suspect it has a broken gear in the door mechanism. I think the good news is that the driver's side vent door motor assembly is the easiest one to remove. In a way this is fortuitous, as I always wanted to take one apart and make a 3d model of "the gear that breaks" so I can 3d print them going forward.

I also now have a vent deflector in hand. Which means I can reverse engineer it and 3d print my "low restriction" version.

[Ed Lijewski]

TMK and IME there is no factory way to remove/reinstall a vent door intact. I tried.

With persistence you may find a material or combinations that provides needed rigidity but possibly also malleability in the direction needed to insert both the drive (motor) end and drone end into the vent housing.

Ideally you should attempt this on a removed housing on your work bench. I have one (center section) you could use if you were interested in that.

But you should just remove those vent doors and go on enjoying Scorpio Bliss instead of pissing away valuable time.

YMMV

[brokencase]

So you don't think I can R & R the driver's vent motor assembly? Please elaborate.

Are you indicating that you have totally removed your motorized vent doors?

I guess I should clarify, I do not intend to design and 3d print new motor doors. Although I like the idea of doing this - but its just is too much work pulling the center and passenger side motor units. IF I WERE TO DO THIS - I would streamline them and print them in polyurethane, with the edges tapering thin so as to form a flexible seal and thus eliminate the foam.

Instead I intend to 3d print new vent deflectors that are less restrictive. (see below)
They will probably not make too much of a flow improvement, but I'm running on the assumption that every extra little bit will help.
The opening is larger, the fins are 1mm vs. the originals that are 2.5mm, elimination of the obstructive side to side mechanism, and there are less fins.

The model is parametric so I can change the side to side angle. I'm guess about a 20 degree angle for the center vents.

Since they are symmetrical, I thought I would add a little pull on one side so if you wanted to flip the direction, you could pull the vent out and flip it around and snap it back in. This way you could point both center vents at the driver.

compare.jpg

frontside.jpg

backside.jpg

[Ed Lijewski]

You can remove the motors; I've done several. Nothing special to it (dash removed first of course). Tight working spaces, but manageable.

I was referring to the vent air deflectors. If you 3D print one that is flexible enough to install, I expect the motors will crank on it to a point of distortion when closing all air flow. From.observation when the EATC powers the motors to close air flow current doesn't cut off immediately on deflector touching the housing and continues for a few seconds. That's why/how the deflectors warp or break.

I think your experimenting on printed vent door material would be easier done on a bench using a motor of course and a vent housing. You can remove a vent housing from your car, just a couple nuts (or screws, can't recall which). The center vent housing contains two vents with power from one motor, so your replacement doors there would work in tandem, with the material you use holding up to the additional stress on full vent closures.

Yes, I totally removed all vent doors. I didn't disconnect the motors as that would set an EATC code. So now the EATC sends power to the motors on start up and continuing for a set time, seems maybe 15-20 seconds. That seems programmed in the EATC as sufficient time to adjust a vent door to whichever preprogrammed position. But the preprogrammed "closed" position is the one that eventually damages the vent doors by powering them too long. Is that a function of a broken gear tooth? I didn't find that to be the case, rather that the EATC continues power to the motors a few seconds longer after doors touch housings than needed.

If your deflector design improves air flow it could only be at the margin IMO.

YMMV

[brokencase]

Certainly removing the motor vent doors will increase air flow. That probably made a big improvement with A/C performance with your setup.

However your problem now is no flow to the front defroster in the Winter time.
What do you do? Close all the panel vents manually?...or worse...stuff your old socks into them?

I think polyurethane would address the "over torqueing" problem for the motor doors. In other words the central region of the vent would be printed thicker (and would be stiffer) but would still have enough give to prevent breakage. But the edges would be thin (about a half millimeter) and would flex and seal like the foam did.

But I don't plan on printing the motor doors, except I may attempt for the drivers side motor vent. Despite your caution I will probably pull that unit out and try to repair.

FWIW, I have observed in spare EATC units blown out vent motor drivers chips. I was able to purchase the driver chip and replace. I think I have about five spares of these driver chips. Could this be the reason for your non success in vent motor repair? In other words your repair was actually good, but you did not realize the driver chip was blown?