Gang,
I'm back to my semi-regular project of trying to quiet a 1966 Starfire coupe. Any lessons here should be applicable to most other 65-70 Olds Cutlass/442/88/Starfire/98. I'm trying to understand GM's window sealing design with an eye toward eliminating water intrusion and minimizing wind noise. I'm hoping some of you might have experience that can guide me & perhaps the photos below show what _not_to_do_ as I go along in my learning.

There's nothing custom about this '66 Starfire, the door hinges are still sound (i.e. don't sag much). There's no chop top or anything exotic. Interior, trim, windows and rubber are mostly stock.

I'd like your opinions about whether these window are adjusted incorrectly. I've spent a fair few hours adjusting them over the years, but I'm not sure I've got them right. I understand the design in general terms, but I'd like to move beyond "good enough" and start measuring to 1/16"'s of an inch to really get the noise minimized.

So, first up, looking at the interface between the drivers side window and rear quarter seal, does this look wrong?:

Should the driver's front window rear edge be close to flush against the leading edge seal of the rear window?

I checked out a few cars online today and am arriving at the impression that this gap is too large. What do you all think? I suspect it's contributing more noise than it should. The passenger side generates more noise than driver's side, but I don't think driver's side is right either.

Long ago I shimmed my convertible roof rail rubber down to make a tight seal against the windows. Then I repeated the process on my hardtop. I'm beginning to wonder if that was just plain wrong. As in, maybe I cured they noise symptom, when the actual disease was saggy door hinges... Here's a shot of the down-shimmed drivers roof rail. It's tight, but to my ears, noisy.:

Have I gone too far shimming this seal down?

After so many (mostly failed) experiments, I'm leaning toward pulling the interior panels and getting the windows as close as I can then finishing up with adding factory rubber. Does that sound right? It could also be that my standards for quiet are just unreasonable for mid-60's cars & I need to lighten up. From what you all remember, were they quiet back in the day? Was it easy to hold a conversation at highway speeds?

Recall that we're talking about a Starfire/88, not a 442. I wasn't very old when these cars were new, so I don't know how quiet they actually were from the factory. All these years later, I'm sure sealing has gotten better and it's not fair to judge these older cars against modern standards. Still, I'd like them to be as good as they can be.

Part of the game with windows seems to be the inward pressure the window glass puts on the seal to keep out water and noise. Is there a good way to measure or set that inward pressure? For example, this driver's side rear window - I'd think it should have enough pressure to force that ear downward, am I right so that I should adjust the window, or just live with it?

Should I set the inward pressure of the window glass higher to keep out water & wind?

VentiPane Windows
GM got rid of vent windows in the late 60's. To me they're part of what a '66 big Olds should look like, but they certainly create noise. Yesterday I drove the Starfire at freeway speed with blue tape over these seals and it made no more noise than as you see them here without a cover. There was no noise difference between blue-taped over and as you see it here. Do these reproduction seals look correct to you all? I think they're right, but am not sure:

Reproduction seals don't leak & don't seem to make noise. Are they right from what you can see here?

Sealing the Ventipane window against the A-pillar
Olds left a lot of adjustment room for the vent window leading edges against the A-pillar. I'm not quite sure what the right settings are. I could snug this forward a bit, but am wondering if this looks right to you all:

Nudge this forward 1/8" to tighten the door-to-A_Pillar seal? Or does this look right?

Do more seals reduce noise?
I've been proceeding on the idea that more seals reduce noise. So what you see here are 2 non-factory oversize seals installed with the idea that seal-crush will reduce noise. Now I'm not so sure. Is it time to go back to factory default and start again?

Do additional seals reduce noise? These are oversize and there's one extra in search of minimum wind noise. Is it time to start fresh from factory?


Front / Rear Window gap

Is this too large?



Should I adjust the windows to make this gap a lot smaller?

Equally on my passenger side, I probably made the same mistake. Is this gap too large and contributing to noise?

Should the front window trailing edge sit more or less flush against the rear window leading edge?

I have lots of ways to minimize gaps - mainly shimming above the roof rail retention steel. But I don't believe that should be necessary. On the other hand, if I don't shim it, I'm not sure the windows can raise high enough to form a water/wind-tight seal.

At this point I'm thinking I want to go back to factory, adjust the windows with rubber out of the car as close, parallel and in/out snug as possible, then add rubber beginning with the SoffSeal reproduction. Do any of you have a better way to suggest?

Looking forward to you thoughts. I'm hopeful that whatever logic we arrive at will help not just the big car people, but also other GM-interested people who'd like to get these things as right as possible given almost 60 years of wear and diminishing memories of what they were when new....

Thanks in advance
Chris

 

You mentioned door hinges a few times. Have you ever replaced them? If you haven't replaced them this is where I'd start.

Also, make sure you're adjusting per the FSM/CSM. I installed new weather stripping in my 71 98 and adjusted the windows per the manual. Since I could only get it close, I took it to a window shop and they "dialed it in" for me.

 

Personally, I don't think you'll ever be able to get it to be as quiet as vehicles are today. These cars were built before there were wind tunnels. They were tested for water leaks and that was probably about it. The elimination of the vent windows was a cost factor and I don't believe it had anything to do with noise. Unless you are hearing whistling it's about as good as you're going to get. When I owned and drove in the 60-70's I don't remember being concerned about noise because the windows would be open to get a breeze and get the smoke out. and the radio would be playing music.
As far as adjustments, from what little experience I have, it can be tricky. It takes a lot of patients to get it right and then when it seems right the temperature changes and it's out again. I replaced the upper window tracks on mine a couple of years ago and last week I brushed up against one with my back and it came out of the track due to shrinkage. Another thing I found was too much inward lean causes the doors not to close right (need to slam to shut).
I hate "it's good enough" but sometimes that's all it can be. Just have to learn to live with the fact that they are old cars and they have quirks that it's just part of their charm. Drive it and enjoy.

 

Many thanks for your time & attention.

The door hinges are not bad at all, only the driver’s door even drops at all, it’s barely perceptible. The drop is solved when the lock latches the peg thing in the rear quarter. I checked yesterday and the passenger side has no drop at all. That’s the good news. Also the paint and body on this car is nice enough that I _really_really_ don’t want to pull the front end off to get at the hinges as I did on my 98…

Also I agree you have to learn to live with some of the limitations of the designs as they were, I’m just trying to make the best of what _was_.

My problem is I don’t really clearly recall how they sounded then because I was very small. And, oh yeah, windows (especially adjusting) takes patience & time. Digging into my past I last took a run at this car’s windows in 12/2020. I’m not unhappy with the noise.

But in true car-guy fashion, I’m trying to see if I can make it better with a combination of parts, time, understanding & ingenuity.

I’m on the road for a couple of days, but will get back at it on Wednesday or so. Just trying to put together a game plan while I’m away so I have a somewhat efficient process when I get back.

Comments and opinions are welcome. If any of you have handy pictures of your front to rear window gaps for mid60’s Olds, I’d love to see ‘em

Cheers
Chris

 

I have fought with glass adjustment on my 69 almost since the day I bought it. I have created a couple threads here over the years discussing it.

The first time I had the door panel off the drivers door I noticed a bunch of glass in the bottom of the door. I can’t help but wonder if somewhere on the past someone attempted window replacement without a clue of what they were doing.

Several years ago as a winter project I decided to replace all the worn out regulators with new power regulators, the adjustment is worse than ever. I’m seriously considering paying a body shop to do whatever it takes to get it right.

 

I read your threads back to when you first underwent this journey. I see you know how to make the adjustments so I don't need to go over any of that.

In your first picture it does look like it's too wide of a gap and in the third picture it looks like the window could go up more. Do you have enough adjustment in the front window to move it towards the back and the back towards the front? The same thing on the passenger side.
In the next two pictures it's hard to see where the edge of the glass is and where the edge of the seal is. I don't know how to make adjustments to the vent window glass within its' frame. Would it be possible to add a strip of rubber in the channel behind the seal so it pushes forward and have more contact with the glass? Where you point to vertical member do the same thing, add material behind the roof seal to fill the gap.

Did you glue your roof seals in? I think I'm going to have to do that to mine.

 

I suspect I’ll wind up shimming the full length of the door opening, perhaps this time with 1” x5/16”’s instead of 1” X 1/4” to get some reduced gap between front and rear doors, unless I can figure out a way in the window travel and placements within the risers (the horizontal pieces the glass bolts to) to get back to factory.

I tried getting my 98 convertible tight without shims and just couldn’t get there. This car has been running above-the-retaining metal shims for years now, but I stopped short of the A pillar and the C pillar to avoid creating a geometry nightmare since forward-back limited motion will also translate to up/down limited motion, but it may now be time to go full length. Not that anything’s really changed, I’m just trying to see if I can make it better.

I don’t expect this car to compete with modern standards, I’d just like to be sure I’ve done all I can up to limited “customization” to make it as quiet as possible.

I’ve been watching a few YouTube’s on caddies and impalas and the like. They recommend shooting a bit of paint on the “before” adjustment settings so you know what to go back to. They also recommend getting the windows centered on the in/out axis at the reveal molding with the windows down before moving onto other steps.

One interesting tidbit from an Chevelle window video was that the rear-most track on the rear windows adjusts the angle or “cockeyedness” of the rear windows. I’ll play with that since there’s a good 1/4-3/8”’s difference between tops and bottoms of my front/rear window seals. Something or other is not square.

At this point I’m probably going to shim the back side of the roofrail retention steel strips with 1x5/16”’s, then screw in the strips and measure for tightness consistency across the retention strip to create a consistent “gasket crush target”. Then I’ll start by installing (but not glueing) the Soffseal factory seals in to give me a consistent target to adjust the windows up to. Then it’s on me to adjust the fore/aft, in/out, up/down and any out-of-square cocking as best I can using the processes I’ve tried before.

I think where I might have gone wrong in the past was setting the windows up 1st, before installing the roofrail rubber which gave me no real target to measure window position against. In 2020, I think I got the window tops all aligned, got the front/rear gap too wide, ran out of steam, and called it good enough. Perhaps putting the roofrail rubber in first this time as I intend to run the car will help.

I’m still on the fence about adjusting the rear windows first or the front windows. I’m not sure it matters, but do any of you with experience have opinions?

I did rears first on my convertible on the idea that the fronts have so many more adjustments that it would give me more opportunity to fit fronts to rears. The other way to see it is get the tough ones first (fronts), then fit the rears to them.

If I can get to “get it through the car wash without towels” and hopefully a little quieter, that’ll be it for this iteration. Most of the time I run this car with the windows down and the radio up. It’d be great to have it quiet for longer road trips though.

Cheers
Chris

 

Best thing to do for your seals is coat them with Vaseline on a warm sunny day and leave them for the day soaking in the sun. They'll become much softer and seal so much better ! (wipe off the excess at end of day)

 

68post,
Interesting idea, never heard that one before.

Would you recommend the Vaseline & sunshine tip for aftermarket seals (like Steele & Soffseal), or does this apply more to factory parts? Also wouldn’t the grease make it harder to glue the seals in, or do you bypass the gluing like I have over past few go-rounds.

Thanks in advance,
Chris

 

Just use it on the glass side once the WS is in place. It basically rejuvenates old seals, but if your new seal leaks air this will help. I doubt it matters the brand. I've kept 8 yr old sunroof seals from leaking this way. Old seals get dry and stiff and this makes them like new again.
Apply it heavy and leave in the sun, then after several hours wipe off the excess.

 

After 2.5 days fiddling with windows, seals and regulators, I got my ‘66 Starfire wind noise down by 10-15%. It’s hard to measure the difference without equipment, but it’s quieter on the freeway and resists water intrusion better than it ever has.What’s below should apply to most mid-60’s GM big cars and may have applicability to Cutlass/442’s as well.

If you’re trying to seal & quiet your windows too, read on.

Background
I’ve had my ‘66 Starfire for about 25 years now. Every so often I try to make it a bit quieter.

I’m no pro, but I’ve experimented with all manner of closed cell foam seals, oversized foam rubber gaskets from Steele and so on. My last go was from 2020 and led me down a path of shimming the top side of the roofrail with a 3/16”’s x 3/4” adhesive foam tape with intent to force the roof rail rubber down tighter onto the window top edges. That wasn’t quiet enough so I tested slightly oversize seals from Steele Rubber as well.

This time I went back to the factory design and committed to adjusting the window glass and the seals at the same time. By the time I was done it was 2.5 days from pulling the interior to reinstalling it. Adjusting windows is a slow and very interative process.

Previously I’d tried to get the windows perfectly adjusted and then put the roof rail and rubber in as the last step. This time I had the roofrail track in and rubber on as I adjusted the windows. Having the rubber installed (loosely) gives you a target to adjust the windows against. I have not yet glued the rubber in in case I want to do more adjustments.

I tried to create consistent sealing pressure along the window top edges and at the seam between the front & rear windows. That meant I cleaned old goop off and straightened bent metal where I could. Here & there i used a digital caliper to get to consistent measurements across glass surfaces.

Tools
Since I don’t work at GM, I used 3M’s strip caulk to replace the old mastic sealant where needed - mainly the rain gutter underside against the body and the top of the steel track that holds the roof rail rubber. 3M’s accompanying solvent is strong and really helps prepare surfaces for a new clean, consistent-thickness new water barrier.
3M water sealing goop and a very useful cleaning solvent

A heat gun works well on stainless trim to help remove old GM mastic water sealant. It also works well to heat clean trim on installation of new sealant: once warm, the 3M goop spreads sort of like frosting on a cake.

A set of plastic trim tools helps you both remove trim and also to scrape the old goop off. I think I got these from Amazon for not much $. The main thing is they don’t mar or scratch finished stainless steel on removal or installation.
Trim removal tools to keep from marring stainless trim when removing or straightening.

If you want to get really picky, use a digital caliper to measure along the way. As my eyes get older my estimates are getting worse and worse.


Much happier about 1/8" vs the larger gaps from a few days ago.

GM’s window to body seal design
Rain Gutters
After the body of the car, the first layer of GM’s sealing design is the stainless steel rain gutter trim. At the A-pillar and C-pillar these stainless trim pieces wrap around the body and are supposed to be more or less clamped/glued into place with mastic sealant to form a water barrier.

I’ve put mine on and off a few times over the years - like for polishing - so they were a bit bent on the underside. I tapped them straight again using plastic trim tools and a few taps with a hammer against the trim tool. They also had varying amounts of GM’s water sealing mastic goop which I used a heat gun to remove.

Roof Rail Track
The roof rail steel track screws into the A-pillar trim, the underside of the roof and C-pillar trim with flat head screws. The screws go into slots on the steel track which allows some inward/outward adjustment of the track. That adjustment turns out to be important, so initially set the trim screws just tight enough to hold the track, but loose enough so you can nudge it in/out as you see fit. Initially set the track screws so that they are centered in their slots.

Like GM did, I sealed the top of my roof rail with the 3M goop. I also stuck on 1/8” of foam tape to have a clean visible edge & shim it down just a tick. Skip the tape if you want a factory look, but some kind of sealant is needed on the top of the roof rail track to keep water from coming in between the body and the track.

Once you have mastic sealer on the top of the track, it’s harder to move the track in/out to adjust it, I used a 1/4” thick plastic stick (like a paint stirrer) to nudge the track in and out.

Roof rail rubber
The roof rail rubber slips into the track. Slip the inside lip of the foam in 1st, then nudge the outside lip in. I work from front to back since the front ends are shaped and need to be in a specific place for their plastic retention pins. If your steel track is clean of previous glue or rubber cement, you can slide the rubber forward and back to get waves in the seal out, or to put a little more rubber in one section of the track to create some additional crush resistance.

Here are a couple of shots of the sealing sandwich. It's almost all factory excepting the Trimlok "P" seal which I'm testing to see if it helps or hurts.


GM's mid-60's sealing sandwich. The straighter and cleaner each metal piece is, the more consistent the sealing target will be for window adjustment.


A pillar seal parts from rear. I put 3M strip caulk between the body & rain gutter and on the top of the roof rail track.

There's more to say, but is this helpful to anyone but me?

 

Chris, your writeup, pictures and details are really great! I'm going to try some of your suggestions. Definately appreciated!

 

I'll just finish this out so I have notes to myself for next time. Hoping this helps you all too..

Adjustment Process
The Fisher Body manual isn’t too helpful about the process for adjusting windows. This time around I adjusted the rears first, then fronts, but all while the rubber seal was in the roof rail tracks.

With all the shiny glass and chrome, it can be hard to see exactly where the glass is tight & loose. For reference, I put some blue tape (curved slightly to match the glass shape) at 1/4” below the top of each window. This gave me a clear picture where things were out of whack and helped me see how deep into the rubber the windows were when raised.


Use a sharpie to put a few dots at 1/4" below the window top, then stripe the blue tape across the dots. Now you have a reference line you can see easily to make window adjustments where you need them. When done, wipe off the dots with acetone or your favorite solvent.

Since my windows were close enough to work, but not right, I started by getting fronts & rears square in the down position. If they’re square to start with, you can tweak them out of square at the top of their travel with the lower adjustment screws to get a tighter seal. You can also adjust the seal by pushing the roof rail track outward, but you’re probably better off adjusting windows to the seal rather than the seal to the windows.


Start adjustments by getting each windows squared to the body when down.

But to adjust the windows as well as possible, you want a good target, meaning you want the roof rail track screws centered in their slots and snugged, but not so tight that it won’t move. If your track has any old goop from previous owners, clean the underside, otherwise the rubber seal won’t lay as flat or consistently as it should and it’ll be more work to smooth it out to create a consistent target.


Typical roof rail screw. Get the tracks centered on the screws and snug them just tight enough to allow in/out movement. Don't forget the mastic on the upper side of the roof rail track to seal out leaks.
I adjusted my windows using what little I knew from before. See this post for the various screws, stops and bolts:
https://classicoldsmobile.com/forums...i-know-139823/

The big learning from this go was
1) start with the windows square relative to the body in the down position and
2) the rear window guide studs and nuts can be used to slight change the angle of the rear window from top to bottom.

Water Testing Midway
One of the bummer parts of this job is you only know if you made a noise improvement on a road test after the entire interior has been reinstalled. But I realized this time that I could water test my window seal adjustments with a hose and fix them in case they leaked without doing the whole interior in/out process

I water tested my adjustments with a hose jet shooting directly at the window tops. I wiped off the water on the outside of the windows and if there were drops, they were on the inside - indicating a leak from a loose seal. Gravity being what it is any inside drops fall directly down from the “loose” or unsealed spot. It kind of tells you exactly what & where to tighten up.

The first couple of times it leaked, then I realized I had to get the mastic sealant on top of the roof rail track and tighten the windows inward in a couple of spots. 3rd or 4th time was the charm and I got it to not leak. At least with the interior out of the car. Once the interior door and quarter panels go in, they move the windows outward just a bit, so you never know until you wash it...

Surprises
I thought maybe my car had been hit before I owned it since the A-pillar to vent window leading edge gaps had a bulge. Nope. It turns out GM cast the B & C body ventipane window frames slightly concave. Check yours with a straight edge.

I made up for this very slight cast-in curve by placing 1/8” thick foam tape on the body-facing side of the A-pillar rain gutter to get closer to a straight line. The tape is hidden and bulges the A-pillar rain gutter just a tiny bit to more closely match the shape of the vent window leading edge.

Still Testing & Fiddling with auxiliary seals (aka non-factory rubber)
A while back I got a roll of Trimlok “P” seals to experiment with. Basically it’s a “bulb” seal that crushes with a load pressed against the bulb. The side opposite the bulb is adhesive backed so it sticks well to car parts and it even resists mechanical loading pretty well - like opening & closing car doors.

This time around I installed the P seal on the door-facing side of the A-pillar interior aluminum trim to create an additional barrier between the door and the car body. I’m not sure it’s helping, but it doesn’t seem to have hurt either. The idea is the door closes tightly enough to squish the bulb and theoretically things are quieter. For some odd reason there was body-to-door gap at the top of my passenger side door. A P seal extending down 4” from the aluminum trim filled it right in.

I took the car for a road test after all that and it seems better. It's not worse & I'm hoping next time I wash it the interior will be dry. Anyway fun couple of days, but I need some Advil from all the stretching, bending and hunching....

Cheers
Chris

 

A little more detail on setting up the roof rail tracks to get the best seal



Start your roof rail track centered on the attaching screws, move in/out to make a consistent seal between the windows and rubber.