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1965 Riviera - blocked or obstructed cowl vents ?


moran75
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Hi all 

 

Re. A/C I’m guessing the blower draws outside air in through the cowl vent…does the vent ever get clogged? Is that a common phenomenon ?

 

only ask as my a/c blows cold, fan motor certainly goes through the gears up to high - but air doesn’t exactly shoot out …I know all is old but instinct tells me should be a bit stronger….

 

I know it could be ducting behind dash but I’m not going to go there 😀…sounds like a can of worms …

 

which made me think of where air comes in to the blower….

 

if it is blocked is there an easy way to get access? I’m guessing not due to the wiper….

 

thanks in advance

 

kev

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2 hours ago, moran75 said:

Hi all 

 

Re. A/C I’m guessing the blower draws outside air in through the cowl vent…does the vent ever get clogged? Is that a common phenomenon ?

 

only ask as my a/c blows cold, fan motor certainly goes through the gears up to high - but air doesn’t exactly shoot out …I know all is old but instinct tells me should be a bit stronger….

 

I know it could be ducting behind dash but I’m not going to go there 😀…sounds like a can of worms …

 

which made me think of where air comes in to the blower….

 

if it is blocked is there an easy way to get access? I’m guessing not due to the wiper….

 

thanks in advance

 

kev

 

It is possible that it could be clogged with a mouse nest. The problem you are describing sounds exactly like the one I had with my 1963 when I first got it. I could hear the fan blowing like crazy but, not that much air coming out of the AC vents. My problem was solved when I replaced the vacuum actuator on the firewall. See the picture attached. Mine was bad and so the door to allow the air from the blower to flow was partially closed. Once that was replaced the door opened and closed fully so air flowed freely and forcefully like it should. Old Air Products sells them and that is a quick and easy replacement. 

 

The blower fan in the 65 is the same as my 63. It has a metal fan.

 

Bill

 

 

Riviera Firewall Actuator.jpg

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Yes, that actuator us shot but it’s propped open at the mo with a piece of rubber😀

 

but re cowl vent….do you think it’s also susceptible to being partially blocked over time thus reducing air flow into the blower? 
 

or does it just not happen ? Can’t find any reference to such a think in forum history ….

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1 hour ago, moran75 said:

Yes, that actuator us shot but it’s propped open at the mo with a piece of rubber😀

 

but re cowl vent….do you think it’s also susceptible to being partially blocked over time thus reducing air flow into the blower? 
 

or does it just not happen ? Can’t find any reference to such a think in forum history ….

 

Is it propped all the way open? Where air going into the heater box and the blower comes from is controlled by a door in the heater box which is controlled by the double vacuum canister attached to the bottom of the heater box. That door also aided by a spring that hooks on that door and to the top of the heater box through a hole in the top of the heater box. Depending on the position of the door inside the heater box you get 100% air from the cowl vents, 100% recirculating air or a combination of the two. Air flow can be restricted by an obstruction such as a mouse nest in the heater box. Remove the blower motor and you can see into the heater box for an obstruction, the condition of the spring and the position of the door. The spring will often break. If you have no obstruction you will be getting a full flow of air. Where the air is coming from depends on how your heater box door is positioned. I believe the 3rd picture shows the door in the 100% recirculate mode as it is closed and not allowing air from the cowl vents in. I believe the 2nd picture showing the spring, the door is all the way down allowing 100% air flow from the cowl vents.

 

Bill

 

 

Riviera Vacuum Actuator 001.JPG

Blower Motor and Spring 001.JPG

Heater Box and Blower Motor 001.JPG

Edited by Riviera63 (see edit history)
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6 hours ago, moran75 said:

Hi all 

 

Re. A/C I’m guessing the blower draws outside air in through the cowl vent…does the vent ever get clogged? Is that a common phenomenon ?

 

only ask as my a/c blows cold, fan motor certainly goes through the gears up to high - but air doesn’t exactly shoot out …I know all is old but instinct tells me should be a bit stronger….

 

I know it could be ducting behind dash but I’m not going to go there 😀…sounds like a can of worms …

 

which made me think of where air comes in to the blower….

 

if it is blocked is there an easy way to get access? I’m guessing not due to the wiper….

 

thanks in advance

 

kev

  No matter if the source of air for the blower is recirc or outside those sources don't just plug up. Bill's suggestion of a mouse nest or your own suggestion of bleeding blower volume via disconnected or leaking duct work come to mind first.

  If you have the controls on AC and the heater turned off there should be no blower volume coming out of the heat vents.   Easiest place to check is the vent in the console by the drivers right knee. If you feel blower volume at the heater vents then the door you have jambed open is bleeding blower volume to the heater system and not the AC vents.

  Are you sure you are getting high blower speed? This must be directed by the A/C blower switch. Your high blower relay is on the passenger inside fenderwell.

 

Tom

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Apologies , Forgot to say I will update situation next time I take car out …in the meantime I have tried the blower motor without starting car and it blew really well  … so maybe my initial impression taken while driving home on motorway was a tad unscientific and premature 😀

 

However i will double check all doors and vents as suggested when I get out in car again

 

1000 thanks 

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  • 2 weeks later...

Hi all

Finally got car out this week …so by way of update / happy conclusion please note the following - whilst in no order of importance / relevance / significance have combined to solve an issue , imaginary or real :

1)upon reflection,  my method of gathering evidence of a perceived issue was maybe not reliable - IE at 70mph on a motorway just by waiving my hand around in front of dash vents

2) I have revisited the rubber prop on the actuator and saw room for ‘improvement’

3)testing and evaluating,  after point two, in a stationary car showed blower was actually very good 😀

4) and no air coming out of heater vents, an additional check as suggested by Tom

 

so all is intact good - thanks all for input. I’ve also learnt a bit about cowl vents - though I’m surprised that although being open to elements they tend not to get clogged over time? .. that’s a rhetorical musing , no need to comment 😀

 

 

all the best

 

kev

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