What is the purpose of the vents between the rear window and trunk lid on a Riviera

On the Riviera, what is the purpose of the vents inbetween the back glass and the trunk lid. If you look in the trunk, the vents are covered by a pan, which catches anything that falls in, and directs it to two tubes. One tube on each side. The tubes go down through the trunk compartment and exit through the floors.

When these tubes get clogged up over time, water has nowhere to go when it rains, and runs out near the trunk seal, causing this area to rust out. This is what happened on mine.

Can I just close the vent holes back and weld them shut? I don't really understand the whole purpose of this systems original design.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

I never really thought about why the vents are there.The designers at GM must have had a reason for it other than atheistics. Mine has a screen under the panel that stops most stuff from getting in there. I read another thread recently that mentioned someone that had covered it with flat metal.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Flow through ventilation (Circulaire as it was marketed) was a selling point in 66. With just the vent on air would flow through the passenger compartment and out through the vented portion at the rear of the package shelf with little resistance. Behind the package shelf vents are about 4 or 5 long slotted holes in the metal that lead into the rear cowl area. Covering these holes is a 30" long or so thin rubber flap that works as a check valve so air can flow out but not in. Once the air flows past this, of course it goes back outside.
Depending how/where a car is stored over the years those drain tubes can get clogged up but usually not so bad that they would overflow before draining.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Like Z. man sez. The louvered 'Circulaire' flow through vents are only applicable to '66-'69 Rivs, the red headed '70 step child Riv has a flat closed panel. Vinyl top cars had a simulated vinyl pattern embossed right into the metal panel, and it was painted to match the vinyl top color along with provision for the vinyl top trim stainless molding. Non vinyl cars had a smooth metal panel.
The rubber trunk drain tubes in the system, that Brian, and Jason referred to, could very easily over time, be clogged with debris, usually an accumulation of fall leaves, or pine and spruce needles that fell through the large mesh filter screen, and clogged the drain tubes.
If you close off the drain holes Brian, water may accumulate in the well below the rear window and seep past the trunk rubber seal.
I think you would be better off, just flushing out the rubber tubes with a good cleaning !! :TU:

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

The flow thru ventilation works too.
When I was younger, a smoker, and had my '66 I used to show off how at speed you could fire up with all the windows closed and the cabin wouldn't fill with smoke.
God, can't believe I did that now.
ou:

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Its the same principle as the 71 trunk louvres - see ventilation in the owners manual if you have one.
here's 71 page

full 71 manual at http://boattail-riviera-by-buick.com/library/owner%20info_manuals/owner%20info_manuals.php

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Thanks. Now that I understand the purpose of it, i'll keep it. I never paid much attention to the package shelf enough to notice the vent in the back of it.

Also, the drain tubes.. Are they rubber or hard plastic? Mine feel like really hard plastic. There's clips on the ends, like it was a rubber hose, but I cannot bend or flex them at all. Maybe they dried up and hardened over time?

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

They are thick walled, rigid, molded hard rubber that has probably got a lot less flexible with age. The lower portion where the drain outlet is located has a thin flat flange with a delicate metal insert (...that is also prone to rusting), and it fits flush to the opening in the raised portion of the trunk floor pan. I used some RTV silicone to seal the flanges where they meet the trunk floor. The upper portion of the tube is held in place with a large spring type radiator hose clamp. :TU:

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

My T-bird has the same thing, but goes as far as having a lever on the dash that controls a vacuum diaphram that opens and closes the rear vent. Has similar looking drain tubes too. As mentioned, at speed it works pretty good. I laughed when I read in the manual that it was designed to let you smoke with the window's up =D

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Yeah, smoking in the car was encouraged back then LOL times have changed as well as cars. I get a kick that my car has 5 ash trays and 4 lighters but no cup holders.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Thats a good one! I never pondered that fact!:beers2:

Come to think of it most old Rivs I've bought whether parts cars or good cars had remnants of old matches, cigarette butts and stained ash trays hiding in various areas. In this day and age even finding an old match pack is intriging. All the restaruants and businesses gave out free matches with their names on for advertising.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Mine Riv had a small metal clip glued onto the dash
I found aftermarket pipe holder with magnet that attached there. (also found a 71 Trojan box, and the missing radio knob after buying another set)
I did smoke in it on its initial drive home -windows closed cause it was raining most of the way the ventilation was superior to anything else i have driven, smoke cleared windows didn''t fog.
No more smoking allowed after I cleanup the yellow on the rear panels ( peral white interior and pipe smoke just dont go together.

Smoking apparatus was a big marketing tool - most dealerships gave out matches, and sold lighters etc - I have a cigarette case, ashtray, lighter,money clip set with Buick logos Late, came in my 89 Park Ave, not sure if they were from the dealership.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Where are the vents on the package tray located?(Duh on the package tray) no really, I looked and I see no sign of any type of vent there and no way of air from inside the car getting into that luvered area.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

66 and 67 Chargers had flow through ventulation as well. very helpful in those long fastbacks with the windows open.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Good question Steve, often wundered that too !! :TU:
On '66 cars I think there were moulded slots in the centre rear plastic package tray, and then they just disappeared from '67 on - maybe just a good idea gone bad, and too expensive to retool the parts, or maybe the slots weren't needed anymore ? o No:

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

heres the 66 fisher body service manual.
and ventilation page from the 67 owners manual






If your looking at your 68 I dont have the pubs - it would like the Toronado second page from body manual and/the 71 (owners manual page up higher in the thread) and air flow would go under and up behind the rear seat.
If these not readable - send an email and I can send you larger ones - or set a download for the whole book if you wish.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

All cars have some form of flow thru ventilation - most don't have louvres in back, - just vents in the door jams, and intakes on kick panels or thru dash.
The 71 Riv system runs the fan at very low speed all the time - don't know about the others.

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

I've been thinking on why the grills went away after 66 and they went to below the seats - My guess, and its just my guess.
Is rear window fogging - if the air going thru the passenger compartment its going to pickup moisture especially in winter with snow off boots and what not. That moist air would condense on the rear glass on it way to the package tray vents. also the e bodies used a blower rear defogger if the air was going thru the rear package tray the blower air would too - instead of up the glass.
If it goes under the seat the air across the rear glass or from the blower would get dragged up the window better and come down on rear seat passengers.
Make sense ???

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

I have the '68 Fisher Manual Rob, and they very conveniently posted an illustration of Cadillac 'E' body and further mentioned that this system was similar to Pontiac 26657, Chevrolet "F", and 16647 Styles. However, they do mention on the Oldsmobile and Buick "E" styles, air comming up from behind the rear seat back flows into the rear plenum chamber and out the exhaust grill located behind the rear window. The rear window defogger was an option, and not all Riviera "E" models had one, on those that do the blower system is self contained, and just moves the existing air in the car. :TU:

 

Re: What is the purpose of the vents between the rear window and trunk lid on a Rivie

Rockstarr...those drain tubes should be soft rubber. I'm guessing the water you are getting is from splits in those tubes, at the bottom of the tubes, especially. Then, water draining into that plenum goes into trunk, at forward ledge, versus down the tubes, onto the rear axle, or thereabouts.