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Is this the same as you posted a month or 2 ago? Asking because I don’t recall seeing anything about an air valve assembly in the bottom of the doors nor have I seen that in a square before.
I’m fuzzy about the different types and when they changed as well. Adding to the confusion I can confirm The Car and Truck Shop has it wrong in their catalog as they showed my model year 1 piece and they are 2 piece. (And they have good prices but suck for returns)
Me neither ,i figured the vents were just there and they grabbed air from the imperfections in the sealing of the door from the windows. But the valve is there, apparently mostly to not let air ambeiently pass into the cab(exhaust)
The tsb was likely issued in 85 and 83 the valve showed up. so it may have went further. Maybe only silverados etc. But the 1980s gm was BAD about updating TSBs to include new models (like now a days they do)
The bottom door vents on the inside of the doors vent out the vent on the back of the door, outside the seal. Air rushing past the doors creates a strong negative pressure pulling air out of the cab.
I always figured they allowed the cab to expel air when the door gets shut. Not that most old truck cabs are air tight anyway
Im guessing baffle to make it less noise and less a direct path. the mod appears to change the operation since it was too restrictive
| Number:90-130-10 Section:10 Date:January 1990 Corporate Bulletin No.: 961004 Subject:FRONT C/V WINDOW WINDNOISE Model and Year:1987-90 R/V TRUCKS TO:ALL CHEVROLET DEALERS Wind noise into the cab area, in the area of the C/V window, may be experienced in some 1987-1990 R/V models. If this condition occurs, a redesigned ventilator assembly is now available. The part numbers are listed below: Left assembly wfth clear glass(P/N 15634471) Right assembly wfth clear glass(P/N 15634472) Left assembly wfth tint glass(P/N 15634473) Right assembly wfth tint glass(P/N 15634474) Parts are currendy available from GMSPO. 1990 R/V vehicles built after the following VIN breakpoints have the new ventilator assembly installed: FlintChevroletLF119088 Figure No. 1
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The relevant change on the new C/V assembly was to the vent seal which now incorporates a double lip design. This difference is shown in Figure 1, and a brief description is listed below. Installation The installation instructions called out in the appropriate light duty service manual remain the same with the exception of the following: The inner lips "A" (Figure 1) are to lay inside the sheet metal while outer lips "B" (Figure 1) are to lay outside over the sheet metal. Additionally, after the assembly is installed and adjusted, look for a gap between the run channel (the vertical support of the vent window) and the outer weatherstrip, which is located at the base of the main window. If a gap exists, Figure No. 2
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slide the outer weather strip forward until it contacts the run channel in order to seal the gap. See Figure # 2. IMPORTANT:If the vehicle experiencing wind noise is a Suburban, Dealer Service Bulletin Number 89-275-10 on "Opera" windnoise should be referenced. |
| Number:89-275-10 Section:10 Date:November 1989 Corporate Bulletin No.: 961003 Subject:REAR DOOR OPERA WINDOW WHISTLE/WIND NOISE Model and Year:1977-86 C, K TRUCKS 1987-89 R, V TRUCKS Figure 1
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Figure 2
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TO:ALL CHEVROLET DEALERS Some 1977-1986 C, K and 1987-1989 R, V Suburbans may experience a whistling sound around the stationary glass (opera window) in the rear side doors. This condition may be corrected by replacing the rubber seal surrounding the stationary window identified in Figure 1. If the whistling condition is found to occur, the rubber seal should be replaced with revised rubber seal (PN 15646933). The difference between the two seals can be identified in Figure 2. The cross section shows that the revised seal has a much larger lip which will decrease the overall level of wind noise. Vehicles built after the following VIN Breakpoint have the new seal installed. KF195886 |
