Please help to remove cowl vent, 1941 Oldsmobile

[Doctor's Pontiac]

I need help to remove the cowl vent lid of my 41 Olds sedan to clean it and check what may be causing some loose play on one side. No specifics in the shop manual and found only minimal information on a Fisher body manual regarding procedure to remove it. The only clear instruction is to first disconnect the linkage under the dash. There are other hinges that are not accessible from below the dash because there is a big box there for the heater and not from above because there is a screen in front, and I can not remove the screen either. I can not imagine the large heater box has to come out for this job.

 

These photos show what I have. I hope to get some suggestions what steps to follow.

 

 

 

View from the L side, can see 2 screws, one in the center and one on the extreme L side attached to the screen. I removed them and no way the screen will come out as there is no clearance on the front part despite the lid already reaching its highest possible position plus this "rivet" shown in photo.

 

 

 

 

From the R side, the screw is missing on the end and again I see this smooth round head that don't know what it is but seems also holding the screen in place.

 

 

I looked carefully at the screen and there is a lot of stuff INSIDE the screen. Debris and bugs are supposed to be stopped OUTSIDE. Is this a filter element or is what seems an abandoned nest?  The interior was in very good condition when I bought the car with no traces of pest having nested inside. There is no odor. It seems to stop any flow of air inside so I presume this is a previous unwanted guest. The dried up cracked gasket visible.

 

 

 

The linkage that connects the cowl with the handle under the dash is easily visible and ease to disconnect with a small bolt with a nut shown in photo. Presumably, this will permit the cowl lid to be pulled upwards once the other hinge bolts are removed. That is what the instructions state without telling how to remove them!I

 

I hope to have input so I can continue the repairs. Thank you very much,

 

Manuel

 

[Oldtech]

Not up on 41 Olds specifically but on most 40's cars that I worked on the vent has to be unfastened under the dash either at the pivots or the complete hinge mechanism. I think the rivets you point out only fasten the screen on. 

[Doctor's Pontiac]

Made no progress. It is impossible to see the cowl from below dash because is covered by big heater box. There must be a way to access from the top once the screen is removed. That is where I am stuck.

 

These are the instructions from the Fisher  manual and schematic of parts book:

 

 

 

HOW CAN I DO STEP # 2 ? Bolts are hidden. 

 

 

 

Thank you 

[JFranklin]

I think it is expected to have the area cleared before doing step 2. Many cars back then weren't equiped with a heater.

[Oldtech]

Bu the picture it looks like the hinge arm pivots (10.310) need to be disconnected. I don't see them in the picture but they could be farther back, I am thinking, like Franklin, that the heater may have to come out.  

One other idea. That seal needs a new one anyway. Pull it out and check that there are no screws under the seal. 

Edited November 2, 2022 by Oldtech (see edit history)

[JFranklin]

Maybe that is a era primitive cabin filter.

[cron1984]

Here are some pictures from my ‘38, not sure if they’ll be of any help. If it’s anything like mine, I wouldn’t try to remove the screen on the vent as you’ll still have to get to the screws holding the brackets to the riveted swivel brackets attached to the body. My vent was spot welded on, yours may have some spot welds hidden underneath (unless someone previously took it off). The cowl vent body will still block access to those screws I believe. 

 

[Doctor's Pontiac]

On 11/2/2022 at 7:34 PM, cron1984 said:

Here are some pictures from my ‘38, not sure if they’ll be of any help. If it’s anything like mine, I wouldn’t try to remove the screen on the vent as you’ll still have to get to the screws holding the brackets to the riveted swivel brackets attached to the body. My vent was spot welded on, yours may have some spot welds hidden underneath (unless someone previously took it off). The cowl vent body will still block access to those screws I believe. 

 

 

Thank you for the very clear photos, I appreciate it. Seems the design of mine is about the same. The back of the vent is always hidden from access given that the vent opens up to the front and is pivoting on the back. I see in your photos that there are 2 hinges, one on each side in the back of the body of the vent that can only be reached from under the dash/cowl.  I wanted to explore as much as possible how this is built so I attempted to disassemble as much of the vent as possible to study the case and I show my findings below.

[Doctor's Pontiac]

I made some progress and at least I could get access to what is going on behind the screen and have room to replace the gasket that is in terrible shape. The cowl vent itself still can not be removed. These are the steps I followed. Please comment if you have suggestions

 

First step was to remove a bolt and nut that connects the cowl handle to the linkage. Hard to reach in my car as everything that could be installed is already there and not much room for anything.

 

Picture shows both handle and linkage separated. I placed a green tape as a reference to the notch that provides tight seal of the vent once it is closed. Interestingly, after linkage was free there was significant play of the cowl vent and appeared will come upwards. I played with it in all directions until it came up enough to expose the entire front screen as shown below

 

 

Had to place a wrench to hold screen in place. Now have access to the screws holding the screen. I was hopeful that behind the screen may be access to rest of hardware that is connected to the hinges so started removing the screen.

 

 

Screen came out only by tilting to the passenger's side and lifting sideways. It was hard but came off

 

 

Now I can confirm that the material seen behind the screen is a type of additional filter that is secured with a metal mesh behind and a few brass paper fasteners. I presume this is not original and hope some of you will be able to comment. The bad thing is that behind the screen there is nothing at all that can be loosened up or removed to get the cowl vent out.

 

 

The linkage is riveted and welded at the top under the lid. The cowl lid has a lot of play and free movement at the passenger's side and does not appear to have anything holding it on that corner.

 

 

Passenger's side shows nothing. Close to the center of the anterior aspect of the cowl body there is a slotted screw that I don't know what is for and can not access what is behind. I did not want to remove this screw in case is connected to the hinge because I will not be able to reinstall unless I totally dismantle the dash, which I don't feel like doing at this time.

 

 

The driver's side has the Z linkage that goes down to under the dash through a rubber boot. When pulling the vent upwards there is definitely something on that side holding in place. If there are hinges on both sides I expected some resistance also on the passenger's side but this seems more to the driver's side only. With tremendous difficulty I introduced my hand and touched the rubber boot trying to feel any nuts or bolts but could not. All I get was pain and scratches all over from very sharp edges.

 

So this may be the end of road to remove the vent, at least for now. I am sure many Forum members have done similar jobs and I would like to hear any suggestions. Meantime I will work on cleaning old gasket and see if I can install a new one. This is also challenging because there is no access to clean the seat of the gasket in the rear section of the vent, where the lid hinges, and which provides only about 1/4 inch space between the lid and the edge of the opening. Will see, thank you for any comments. Manuel

 

 

 

[EmTee]

6 hours ago, Doctor's Pontiac said:

Now I can confirm that the material seen behind the screen is a type of additional filter that is secured with a metal mesh behind and a few brass paper fasteners. I presume this is not original and hope some of you will be able to comment.

That mesh filter and the perforated backer held by a brass screw sure look original to me...

[JFranklin]

4 hours ago, EmTee said:

That mesh filter and the perforated backer held by a brass screw sure look original to me...

So I accidentally hit the truth in my last post above, what do you know? It should be able to wash the filter to put it back in good order.

[Doctor's Pontiac]

Yes, you are right, it is a dust filter. Found this drawing in the parts manual under “accessories” and it mentions the dust filter but no part number. Evidently what I have is from factory. This illustration also shows the cowl vent lid on top of heater and the flow of air but provides no information on the location of hinges. I will study the heater and see if I can handle removing it. Another winter project!
 

[Doctor's Pontiac]

I started this post because my cowl vent lid seems loose when fully open and I wanted to adjust it and because the cowl vent gasket needs replacement. It is now evident that I can not make any adjustments unless I have full access to the hinge under the cowl which I won't do because requires removal of heater, is a major job. Therefore, I decided to replace the cowl gasket "in situ" without removing the lid. The shop manual has one line stating that it can be done without providing specific instructions and therefore I had to explore the process to follow. This was my first time doing this job.  I took many photos to document the process and decided to post in case someday may help other enthusiasts who like me have no previous experience.

 

All the initial steps were described earlier in this post and I follow from there.

 

1. Removing the old gasket and cleaning the gasket channel. The shop manual's language gives the impression that you just pulled the old gasket and it will come out easily. I presume they never imagined it will be still attached to the car 80 years later to the point of being fossilized into the channel, hardened like a rock and requiring hours to remove it given lack of space in the posterior channel where the opening to work is only 1/4" and in a very uncomfortable angle

 

The rear of the lid is the big challenge. The more open the lid is, the more posteriorly it tilts preventing the insertion of any tool into the channel for cleaning it. This photo taken after the bulk of the gasket was already removed

 

 

The front of the lid is very accessible to remove old gasket and begin cleaning the channel. It gets complicated on both ends, R and L and is virtually impossible on the rear part of the lid. Had to keep lid open at the exact best angle all the time - which usually requires an extra hand that I did not have - to reach the channel

 

 

 

This is the only tool that effectively worked to remove dried up cement and old rubber from the posterior channel. You can appreciate how narrow the space is, which hardly accommodated this hook pick. It got stuck all the time in this hardened crusted material to the point that one of the picks broke down trying to extract debris from the channel. I tried several plastic upholstery tools but they don't fit in. Used a 3M adhesive remover as recommended by Steele Rubber to soften up the old material until eventually most of it was removed.

 

 

Channel is getting cleaner.

 

2.  Installing gasket. I used a gasket sold by Steel Rubber, which is the exact size of the original and appears very accurate reproduction.

 

 

I placed a "dark cross" on the upper aspect of the old gasket as a reference and compared side by side with same spot on the reproduction. This step is necessary to know which side of the gasket is up and which is down.

 

 

This is the bottom of the old gasket compared with the new one confirming which side is up and which is facing down.

 

 

Now came the messy part of the job. I applied masking tape to protect all surrounding area from getting the nasty rubber adhesive..

 

Getting preparation done before applying the weatherstrip adhesive.

 

 

 

The only tool that fit in the narrow 1/4" gap. I placed the gasket adhesive in a piece of cardboard, picked it up with the brush and applied to the gasket channel and to the bottom of the rubber seal, waited until getting tacky and then applied it into the gasket channel beginning with the rear side of the lid, which is the most difficult, and then coming forward on the corners and eventually to the front area which was the fastest and easiest part.

 

3. Adding the screen and filter. The filter is basically a dried vegetable, looks like hay or some type of grass and is packed as a sandwich between the metal screen in the front and a backing plate behind. Very delicate material that can not be cleaned effectively because it falls apart when disturbed. Best cleaning method is to place in hot water with the backing plate holder attached. I left in a sink for 30 minutes and a lot of powder was removed (shown below).

 

Only safe way of cleaning this dried vegetable material. I submerged entire piece in hot water and let it sit there for a while.

 

 

The dust filter is attached to the backing plate with a couple of staples that I did not notice until after cleaning. It helps to keep the unit complete. I added 2 staples toward the center in addition to the 2 localized on each end. The material is then applied loosely to cover the staples and are not visible. 

 

The dust filter is then attached to the screen in front using "paper fasteners" that were described at the beginning of this post. The screen body is now ready to be hooked to the cowl vent lid and is secured with 2 screws as shown in the last photo below

 

The gasket is visible and looks good

 

4. Completing the job. Last step - which I still did not finish fully - is to clean debris of gasket sealant and apply touch up paint to edges of the cowl lid. 

 

Sorry for the long post. Hope helps somebody

 

Manuel

 

 

[GARY F]

Great job and looks good.