760 Cabin Air Filter

Hi all,

I am now the proud owner of a 1988 760 GLE.

And, of course, I have a question: not long ago there was a thread
here regarding blocked-up filters that were meant to clean the air
that was drawn into the passenger cabin (pollen filter?). Does the 760
have such a filter? I ask because the heater fan can be heard working
but nothing is coming out of the vents so I suspect this filter is
clogged shut. If there is no such filter then any advice on where I
might start looking would help.

I figure if something crawled in and died in the months the car was
sitting I'd be able to smell it.

Thanks,
blurp

 

No filter in the 760s. Is that the Automatic Climate Control (ACC), with a
"calibrated" temperature wheel and a mode selector lever? If so, you can
expect it to be a vacuum problem - either the vacuum source is not giving
you vacuum or the controller is haywire... uh, hay-vacuum hose.

Mike

 

Check for vacuum leaks from the servo pipe junction to the air conditioning
inside the car. There is also a pipe that goes to the temp sensor in the
central roof light housing. There is no pollen filter as such but if the fan
is rotating but air is getting nowhere then check the vacuum modules and
valves in the air con unit (this is why air con costs a lot to maintain).

Cheers, Peter.

 

The cabin air filter was not introduced until the 850 series in 1993
as an option and standard equipment after 1999 on all models. It was not
available as a retrofit for the 700, 200, or 900 series. The
heating/air-conditioning system is set to default to defrost mode if the
controller is not functioning properly.

 

Based on your suggestion I was able to track down the attached
diagram. Because I can hear the Recirculation Shutter (36) open and
close I know that vacuum is being supplied to the Solenoid Valve Bank
(21) and conclude that the vacuum connection from the Bank (21) to the
Vent Shutter (35) is damaged.

I don't have a Haynes for this car yet so I'm hoping someone can tell
me the location of the Solenoid Valve Bank so I can start tracing the
line. I didn't see it under the hood so I'm guessing a footwell...

Thanks,
blurp

PS Found that diagram on the Volvo Club of Thailand board.

 

Referring to the previously attached diagram...

I have tested more thoroughly what works and what doesn't (in a quiet
place off the road) and have determined that the Solenoid which
controls the distribution of the vacuum is working on several fronts:
- I can hear it open and close the recirculation shutter (36)
- I can hear it open and close the Defroster and Floor shutters (33)
- I even think can hear it open and close the Bi-level shutter (34)

So this means that the Vacuum Check Valves under the hood are working
properly (31) and supplying adequate vacuum to the Solenoid. Also, if
there was some vacuum failure in the line to the interior temperature
sensor it would starve the whole system of vacuum. Does this sensor
(25) then give electrical feedback to the Solenoid (21)?

At this point it seems one of three things is likely the culprit:
1. The vacuum line connecting the Solenoid to the Vent Shutter is
leaking (or the Vent Shutter Bellos is damaged)
2. The Interior Temperature Sensor has somehow malfunctioned and is
not telling the Solenoid to open the vent
3. The Solenoid itself is faulty.

So my questions are as follows:
1. Where is the Solenoid located exactly?
2. Where is the Interior Temperatore Sensor located exactly?
3. Where is the Vent Shutter Bellows located?

I have to go order a Haynes today but it started snowing today and I
figure I need to getthis working really soon. Any advice/diagrams
would be greatly appreciated.

Thanks,
blurp

 

Hi Blurp, make sure that you get the later (UK) version of the Haynes (Blue
cover, Haynes number 1258), as it covers to 1991 (not diesel or 16-valve
though). IPD stock them usually.

Cheers, Peter.