I have a '93 240 wagon. My wife has asthma and I would like to retrofit a cabin air filter into our Volvo. Does anyone know a way to do this?

Robert

 

wild guess says, only with great difficulty. the heater box on those is deep under the center of the dashboard, the intake air comes from the cowling in front of the windshield into the top of the engine side of the airbox, right up against the firewall.. only way I could see to fit a filter would be to take the whole damn under-dash and center console apart, extract the heater box, then custom fit a air filter to the intake side, reassemble it all, and put the car back together. my son recently replaced the heater core on his 940, took him like 20 hours. oh, and when your nice new filter plugs up? repeat the experience :-/

 

What about a 1990 740GL? The interior is quite messy due to the dust+ that gets sucked in - I have not looked yet - what about a simple one? I'd live with 50% less airflow to have clean air (or better - carbon filtered air).

 

here's the airbox on a typical 940. late 740 is virtually the same.



the fresh air is sucked in from the cowl through '4'. it blows past the a/c evaporator 28, and if volvo put in a filter (they rarely did) it would be #29, then across the heater core #22 which is inside halves 23 and 24, and sent out various orifices via the distributor box #16... afaik, you access this filter by removing the blower fan (#13) and the lower fan/ac cover #21, this is all above the passenger footwell.

here's a different view showing how its connected to the ducts.


after going past the ac evaporator and the heater core (all inside #1 in this pic), floor heat goes out through #19, dashboard air through 10, 13, & 14, and defroster through 7. 22-27 direct some of the floor heat to the back seats.

the 740/940's ventilation system is much nicer than the 240's


ps. activated charcoal (carbon) filters A) block a lot more air, B) plug up a lot faster. I'd use a free flowing furnace style filter for this.



oh, hey. www.tascaparts.com has the *real* Volvo filter for a 1990 740 for $18! its P/N 1307522

 

Hmmm. First I thought, impossible! But looking at the top 940 schematic, it may not be too hard to adopt a filter to fit at #19 where the air actually is sucked into the system. You can remove the leaf guard grille, between the hood and the windshield, and fashion a filter box over where the air inlet is, right over the fan motor. This location is much easier to access since it is outside the whole system and there is plenty of room to work. The location is pretty much where later cars with such filters usually have them.

 

here's whats above that intake duct



the trouble is, I don't think you can take any of those cowl pieces apart, but apparently there's 'netting' in there, both #14 (right under the cowl intake vent) and #31 (above the fan inlet opening, under the rain cap). anyways, I think I'd stick with putting the filter in where it goes, #29 in my first picture paste, a few posts above.

 

The cover plate is held on by three bolts, and usually the netting falls down and has to be reglued with new butyl tape. There is a nice space there, where one can make a filter box to place over the air entry hole...

The other way, at #29 is not a good option as space is minimal (filter there is just a thin grate), labor wise it is a major problem, (heater core access), and what about replacements? You'd do it every 6, 12 months? You'd pretty much have to re engineer the car's interior for that option...

 

Thanks for all the detail Pierce and information Lev. I'l start at #29 and and see what condition the filter is in - I quite expect the factory filter to be finished.

About charcoal filter - I was behind a diesel truck at the Oakland Airport the other day in our 1997 E320 - and smelled NOTHING. We run the charcoal filter (its a button on the dash) all the time. Sure they are $90 to replace but we rarely smell anything - be it cow dung on I5 to LA, diesel, or some random stink. Its our first car with a cabin filter and we are hooked. Our previous family car - 1997 Pathfinder - would blow a LOT sand on us every now and then (we lived by a windy beach).

So we want to see what can be done for the Volvo in this regard - and at 235k I am open to re-engineering the interior.

 

This is not really a filter at #29, nothing like a cabin filter you are hoping to find! It's a thin grille and it's not even replaceable as a maintenance item-don't know why they even call it a "filter". Volvo did not offer a cabin filter in 740 0r 940 or even 960! Even accessing this (heater core) is the nightmare of Volvo repair-it is said that Volvos were built around the heater core... Shops charge 8 hours to change it.