[DML] Re: AC blows intermittently

["content22207" <brobertson@xxxxxxxxxxxx>]

Do you lose the door vents at acceleration as well? If so, your vacuum
canister isn't holding vacuum -- either a bad check valve or a leak
somewhere after the check valve. The line from the canister to the
front of the car is hard plastic, just like an OEM clutch line (line
back to the heater core shutoff valve is hard plastic as well). Mine
cracked, creating a vacuum leak that ultimately melted my driver's
side spark plugs but mercifully not the pistons (see the pic in
#5939's photo album). The passenger side intake rail, which supplies
HVAC ductwork vacuum, also feeds the driver's side cylinders.

Use a hand vacuum pump to pull a vacuum on the HVAC plumbing
immediately after the check valve. It is holds, check valve itself is
bad (has a little diaphragm inside that can leak). If not, start
checking the plumbing at each junction forward. In lieu of the hand
pump you can pull a rudimentary vacuum by simply sucking on the hoses,
but not until after the canister (takes a fair amount of vacuum to
fill the canister). HVAC supply line runs under the console, inside
the passenger compartment (as does the little line back to the heater
core shutoff valve).

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "Greg Linstad" <glinstad@xxxx> wrote:
> After working perfectly last year in VIN #6214 (automatic trans), my AC
> now blows steadily at idle or coasting at any speed, but rapidly slows
> down to almost no air movement upon acceleration. It acts like old
> vacuum actuated wipers where going up a steep hill made the wipers stop,
> and you had to let off on the gas momentarily so the wipers would start
> again. The car runs perfectly, no obvious vacuum leeks or hissing sounds
> from the switch area, and no loose or disconnected hoses that I can
> find. And as I said before it worked perfectly last year. Additionally,
> it now only blows out the armrest vents, not the ones above the radio.
> This seems like it is a vacuum related problem, but I'm stumped as to
> how too find and fix it. When I first noticed this I did get the center
> vents to work by moving the mode switch back and forth between settings,
> but now no setting causes them to work.
> 
> Any ideas? 
> 
>  
> 
> Greg Linstad (my real name)
> 
> VIN #1216 (just got this 8000 mile car, sold my trusty VIN #3507 to my
> Brother Jeff)
> 
> VIN #6214 (11,000 miles)
> 
> 
> 
> [Non-text portions of this message have been removed]








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