Where did all the air go?

[Toby Arnot]

I am having air delivery issues with my "new" '81 Malibu Wagon. I can hear the blower and it sounds like it's moving a lot of air. When I switch on the A/C, I can hear the damper/valve opening and get some air flow out of the dash vents. Not much,but some,and not very cold "sorta' warm. I had the R-134 vacuumed and refilled.
The question holds. Where did all the air go? Trash in ductwork? Leaking ductwork? Thought about the heater control valve, but problem is volume of air.

 

[ssn696]

Is it coming out of the heater duct below the radio? Could be a vacuum line has popped off or broken so the air is not routed through the evaporator?

 

[Ribbedroof]

Sounds like the blend door is not working.

The OE service manual has a diagram of the vacuum lines and where they go. I'll look around to see if I have a pic of it.

And, I'm sure the ductwork is leaking as well. The foam tape used to seal the joints has probably disintegrated by now. When all the ducts are clean and properly sealed, it does make better airflow, but it's never going to be as good as newer stuff.

Also, I have found that a lot of these cars have a pretty fair amount of "gunk" on the evap core in the heater case. You may need to pull the top off and clean it out.

 

[Bonnewagon]

I have a wagon too and when I used the AC, little came out the dash vents. So in summer I jam some rolled up towels into the bottom most big duct that dumps at the floor to force the cold air out the dash ducts. There is a splitter on the very bottom that divides the air to driver and passenger sides. I had to remove that anyway to fit my Firebird console so that left just the big duct with the door. I know it's a hokey fix but it worked and I am not up to removing and resealing all the ductwork at this time.

 

[axisg]

another thing to check is under the hood. Where the 2 AC lines go into the HVAC box the original foam is often rotted or missing. This allows a lot of air to blow into the engine compartment instead of the car. I filled mine with a sealer they use in electrical work. It comes in a small brick and the consistency of plumbers putty. Wont dry rot shrink or grow mould. I think I have seen it a HD in the electrical aisle

 

[Longroof79]

I'm wondering if spray foam is sufficient to use to seal the HVAC box? I know they usually come with some type of sealer around the evaporator lines. I probably could've done a better job sealing the duct work. Oh well, I'll find out once everything is in place.

Axis, what is the product called that you used?

 

[axisg]

Its in the electrical aisle, Called duct seal or electrical putty. Small brick about 6" x3" x 1". It was like $5.00

 

[Longroof79]

Its in the electrical aisle, Called duct seal or electrical putty. Small brick about 6" x3" x 1". It was like $5.00

Thanks man, I'm going to check it out. So it remains pliable then...much like plumbers putty...cool!

 

[pontiacgp]

Thanks man, I'm going to check it out. So it remains pliable then...much like plumbers putty...cool!

if it's $5 in Canada it'll be pocket change for you...haha

 

[Longroof79]

if it's $5 in Canada it'll be pocket change for you...haha

What a deal... 🙂