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Thread: 1995 Silverado Heater box mode valve removal

  1. #1
    Join Date
    Oct 2000
    Location
    stanfield,n.c. , usa
    Posts
    8

    Default 1995 Silverado Heater box mode valve removal

    I have a 1995 Silverado 6.5 TD that I was getting noise from the heater box / air distribution case when air was going through it. Turns out that the problem is there is a gate inside of the heater box at the floor where the air comes out called a mode valve operated by the mode motor/actuator which by what ever position it is in determines which vents the air comes out at, AC, Floor or defrost. The rubber seal that is on the edges of gate or valve is shot and making the noise. My question, is there a way to replace just the gate/valve without totally removing the whole heater box which looks to be a major job?
    Banjoron...95 Silverado 6.5 TD 2WD Automatic

  2. #2
    Join Date
    Apr 2003
    Location
    Michigan
    Posts
    138

    Default

    If you can get to the shaft and remove the actuator lever (one screw) you can put an o ring over the shaft to stop the noise. I believe you can do it from the driver side floor, see the shaft and the actuator. Felt works good behind the o ring also. Some good old fashioned rigging from the mechanic days. Hope this helps.
    Slim

    1995 Chevy 2500,4x4, 5 spd, 6.2 .040 over, 18:1 ceramic coated pistons, Ported 6.5 turbo heads,6.5 high pop injectors, Gm-8 turbo ported turbine housing, custom intercooler, gm dual thermo, 130 gph water pump, 3 to 3.5 turbo down pipe to 4 inch exhaust. Custom electronic adjustable waste gate (got the idea from the Honda guys, Thanks), custom frame mount FSD cooler.

  3. #3
    Join Date
    Oct 2000
    Location
    stanfield,n.c. , usa
    Posts
    8

    Default

    The noise is coming from the air whisteling around the rubber seal that is on the outer edge of the mode gate/valve being messed up an partially missing. You can yiew the gate by taking 1 screw out of and removing the plastic schroud that supplies air to the floof. I have a new gate in hand but just have to figure out how to install it with out removing the whole heater/Dist. Box.
    Banjoron...95 Silverado 6.5 TD 2WD Automatic

  4. #4
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
    12,282

    Default

    I hate to be the Harbinger of bad news but I am pretty certain that the box has to come out so you can seperate the halves to get to the control doors.


    Yup Ma General did not do us any favors with the HVAC stuff.
    Steering column has to be dropped and the dash loosened and lifted up so the HVAC box can clear sand come out. Coolant has to be dropped as well as the refrigerant dumped off the system.

    Not a pleasant thought I know

    Robyn
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  5. #5
    Join Date
    Apr 2003
    Location
    Michigan
    Posts
    138

    Default

    I used to do a lot of dash work in the dealer ship in my later days. New guys do grunt work old guys do clean work. So that being said we did some pretty wild things to beat the time on most jobs. Never had come backs either, FIX IT RIGHT the first time,or it cost me money the second time.

    Look at the heater box and SEE IF YOU CANT SHORTEN THE TIME. The repair manual procedure was dreamed up by an engineer: (no offense) but hey we know they only deal in the actual not the practical. OK enough slamming, and (my brother is an engineer: we have had many enlightened conversations) so don't bash me for the comment.

    Look closely and have a few cups of coffee and look some more then you may have an epiphany (Idea) on how to make it work. It gets old hearing how tuff everything is going to be, most jobs are just time consuming and not hard.

    Hell theft work in the dealership was gravy money, I dam near retired on that type of work. The worse it looked the more money I made.

    Good Luck
    Slim

    1995 Chevy 2500,4x4, 5 spd, 6.2 .040 over, 18:1 ceramic coated pistons, Ported 6.5 turbo heads,6.5 high pop injectors, Gm-8 turbo ported turbine housing, custom intercooler, gm dual thermo, 130 gph water pump, 3 to 3.5 turbo down pipe to 4 inch exhaust. Custom electronic adjustable waste gate (got the idea from the Honda guys, Thanks), custom frame mount FSD cooler.

  6. #6
    Join Date
    Oct 2000
    Location
    stanfield,n.c. , usa
    Posts
    8

    Wink

    O.K It can be done without totally removing the heater box. The section of the heater box that houses the mode valve/gate is a two piece part held together by four clips. You can get to the front clips to take them off but not the rear ones. Once the front clips are removed you can open the side towards the interior of the truck, and pry it open just enoulgh to work the plastic gate down through the hole at the floor where the air comes out. Then in reverse order put everything back that was taken off. The two case pieces are kind of keyed so be sure all joints are back fitting properly before the two front clips are reinstalled. Everything works and cycles the way it is supposed to now without the air sound. Thanks to all who replied to my problem.
    Banjoron...95 Silverado 6.5 TD 2WD Automatic

  7. #7
    Join Date
    Apr 2003
    Location
    Michigan
    Posts
    138

    Default

    Great news, that is why I like this forum so much.
    Slim

    1995 Chevy 2500,4x4, 5 spd, 6.2 .040 over, 18:1 ceramic coated pistons, Ported 6.5 turbo heads,6.5 high pop injectors, Gm-8 turbo ported turbine housing, custom intercooler, gm dual thermo, 130 gph water pump, 3 to 3.5 turbo down pipe to 4 inch exhaust. Custom electronic adjustable waste gate (got the idea from the Honda guys, Thanks), custom frame mount FSD cooler.

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