850 Wagon 1995 - mildew odor in vents

My 850 wagon heat and AC vents smell of mildew any time we have a couple of
damp days in a row. I had the local volvo dealer replace the filter under
the hood and spray it a few months ago, and that helped a bit for a while,
but then the odor got worse again.

I bought a can of some sort of aerosol that claims to help. Where are the
vents I should shoot this stuff into on an 850 wagon?

Is there anything else I can do?

Thanks.

Charlie

 

The vents are the ones at the base of the windshield. To do a better
job, you can remove that plastic panel (5 screws, 2 hoses) and spray
directly into the air intake. While you're in there, you can change the
cabin filter if you have one, or put the kit on if you don't. While
this will not help your current problem it will slow down its
reoccurance.

If you're really serious, you can remove the glove box, knee bolster and
heater motor and spray the stuff directly on the evaporator.

 

Volvo also has a second level of treatment to clean out the inside of
the climate control system. They use this if the spraying doesn't work.

Volvo has solved this problem on newer models by creating the following
sequence after the car is shut off.

1) The AC is shut off or an extended time that seems to run from a
half-hour to several hours to permit condensed water to drain from the
system.

2) The AC fan is turned on to dry the inside of the AC unit of residual
condensate and general wet conditions that foster the foul odors.

I don't know how you could accomplish this on a '95 other than shutting
the AC off before you get where you are going and turning the fan up on
high.

 

I've never experieinced this problem with my 94 850 Turbo wagon. Is it a
problem only in high-humidity climates?

 

It sounds like water is getting into the system, or water is stuck in the
system. Does the AC drain water when its running? If not, that could be
the source of the problem.