[vigsom]

A couple of months back, I wanted to do preventive cleaning of the Cabin Air Filter on a Pajero Sport.

I've done this on several of my cars and my friends' cars in the past; took the glove box off to access the Cabin Air Filter cover, but on this car, found a nice plastic panel which "shields" the ugly looking wiring and AC blower assembly.

I opened the screws on the plastic panel, removed the clip holding the passenger airbag coupler to this panel, removed the panel and what did I see in an expensive import? No Cabin Air Filter

Importance of the Cabin Air Filter

I don't need to elaborate on the health benefits of this filter, but purely from a reliability standpoint, just having a cabin air filter with a robustly built AC saves it from a potential service.

Some examples to support this:

1. My 2005 Type2 Corolla H5 which is now with a friend is still on the original AC with the original refrigerant - beat that if you can

2. My 2007 Grand Vitara AC is also stock

3. My 2003 Corolla H4 had a nightmarish AC because its evaporator core had leaked and it took several rounds of diagnosis to find that. The core had leaked only because the dust on the outside had befriended condensation to cake up and eat the core from the outside. Reason? Only a cabin air filter frame with no filter on the 2003 Corolla.

I would add - no AC technician that I know can ever restore an AC to its factory state w.r.t troublefree performance because there is some step in the process of recharge of refrigerant that isn't done properly e.g..vacuuming (evacuation) is done in 10 mins while good practices recommend 30minutes plus.

Alright, here's how I went about the cabin air filter. I used the opportunity to clean the system out to the extent possible.

1. Got a Cabin Air Filter made by Zip Filters; took approx 14 days to be delivered.

This is a plug n play filter and doesn't have a cover on the filter housing like in other cars.



2. Took the glove box off to reveal the plastic panel



3.Removed the plastic panel which is held in place with screws on the side and just one plastic pop button at the top center.

4. Unclipped the passenger Air Bag coupler



5. Using a sharp cutter, cut through the air filter frame to remove the sealed portion - it came off in 2 parts which looked convenient.







6. The inside was full of dust so I decided to remove the kick panel below the blower, remove the blower, and clean the entire duct out



- by opening the fresh air flap I could access the flap and a portion of the upstream from beneath the blower housing - not easy but not impossible either.

- cleaned the blower suction and the blower discharge duct too till wherever I could reach using a dry cloth then using cloth dipped in surgical spirit.



7. Cleaned the blower lobes using wet tissue - this took approx 45 mins to do. Using hi pressure water was an option but I wanted it to be a dry operation

There is a small hose below the blower through which the blower motor is cooled by air from the blower discharge.



8. Closed the fresh air flap, and installed the cleaned blower



9. Installed the cabin air filter with two flat head wood screws to keep the filter in place.



10. Tested the AC and found the air flow excellent.

11. Re-installed the plastic panel, with the airbag coupler clipped on

12. Installed the glove box.

Paisa vasool !!!

[GTO]

Mod Note: Thanks for sharing! Thread moved to the DIY forum.

[dhanushs]

Wow. Thats a neat installation. Especially in India no cabin filter is not really happening and the evaporator gets clogged up.

Thanks for the update. I'm sure it'll help fellow owners.

[Ravi Parwan]

I remember doing a similar installation in my 2010 MS Dzire VDI. that came with a single piece panel which I cut from only 3 sides and used the third side (top) to retain the panel as a cover for the air filter element. That fix was done within 6 months of buying the car and the car's AC continued to perform splendidly (with regular filter changes) till we sold her off in 2018 due to the NGT rule.

Another thing I generally do is take out these filters every couple of weeks and dust them by gentle tapping against a flat surface. you will be surprised by the amount of dust that collects within 2 weeks, even on recirculate mode.

[ruzbehxyz]

Thanks for sharing.
I too clean and change the cabin filter in my Endeavour. I recently purchased a Bosch cabin filter of same size and replaced it with the OEM filter. However when I start the AC, there is a dull/dampness smell initially which last for a few seconds and then goes. I have used various AC filter foam cleaners, but these are mainly like perfumes which last for a few days/weeks. I think I am missing something.

[vigsom]

Originally Posted by Ravi Parwan

I cut from only 3 sides and used the third side (top) to retain the panel as a cover for the air filter element.

you will be surprised by the amount of dust that collects within 2 weeks, even on recirculate mode.

That's a nice jugaad - to use the fourth side as a filter cover. I am sure a stock fit cover would have been available.

Dust collection on the filter in recalculate mode is a function of how dusty the car is. I keep my cars (mats especially) as clean as I canIn all my cars, I've cleaned the filters once in 3 months, but have never replaced any of the filters because it wasn't needed.

Originally Posted by ruzbehxyz

However when I start the AC, there is a dull/dampness smell initially which last for a few seconds and then goes

The dampness is because there is always some trapped moisture with a little dust inside the ducts, and on the evaporator (cooling coil).

Once the compressor starts, the smell would go away; nothing to worry about.

[ruzbehxyz]

Originally Posted by vigsom

The dampness is because there is always some trapped moisture with a little dust inside the ducts, and on the evaporator (cooling coil).

Once the compressor starts, the smell would go away; nothing to worry about.

Exactly. The smell goes in seconds after starting the AC.
Thanks for clarifying.
First I thought it happens mainly in the monsoon season, but this happens in the dry season as well.
Since I like to keep my car in A1 condition, is there anyway I can get rid of the dampness ?

[vigsom]

^^ There are some commercially available foam cleaners like 3M. I haven't tried any of them but they would only be partially effective, as you've mentioned.

A majority of the dust is trapped in the evaporator fins, and that cannot be removed by foam.

If you're game for an experiment, you could try this :

1. Remove the filter to be able to see the blower

2. Start the blower only

3. Spray a little cleaning foam onto the moving blower. It will help transfer the cleaning foam into the duct.

4. Repeat step3 using a shot spray every 20 seconds and see if you're getting dirty liquid from the evaporator drain (under the car).

5. Continue till you see the colour of liquid at the drain getting better

Once this op. is over, put the filter back, and put the AC into normal operation for a while with windows open before setting off.

This isn't a substitute for regular service but will definitely help.

[Ravi Parwan]

Originally Posted by ruzbehxyz

...when I start the AC, there is a dull/dampness smell initially which last for a few seconds and then goes. ....

you could also combat the damp smell by switching off the AC 1-2 min before shutting the blower. that would help in drying out the evaporator so that you don't get the smell next time.

Originally Posted by vigsom

That's a nice jugaad - to use the fourth side as a filter cover. I am sure a stock fit cover would have been available....

but at the time the thought just struck, I tried it out and it worked very nicely for the next 8 years...

Originally Posted by vigsom

...Dust collection on the filter in recalculate mode is a function of how dusty the car is.

I can do the hygiene at my end, but kids and wife don't bother so much. and I stopped reminding them once I realised the futility of doing so...

[ruzbehxyz]

Originally Posted by Ravi Parwan

you could also combat the damp smell by switching off the AC 1-2 min before shutting the blower. that would help in drying out the evaporator so that you don't get the smell next time.

Thanks.
Well noted. I will try it like that. Just a question. Should I switch off the AC in recirculation mode or fresh air mode ?

[Ravi Parwan]

Originally Posted by ruzbehxyz

Thanks.
Well noted. I will try it like that. Just a question. Should I switch off the AC in recirculation mode or fresh air mode ?

Recirc should be fine. the point of switching it off is to reduce the condensation effect on the evaporator. as the hot air continues to blow over the no longer cooling evaporator, it brings the gas in the evaporator to the ambient temperature, which in turns prevents more condensation forming on it once the AC is switched off.
Lo and presto, no more damp smell.

[ashvek3141]

Originally Posted by ruzbehxyz

However when I start the AC, there is a dull/dampness smell initially which last for a few seconds and then goes. I have used various AC filter foam cleaners, but these are mainly like perfumes which last for a few days/weeks. I think I am missing something.

Originally Posted by vigsom

The dampness is because there is always some trapped moisture with a little dust inside the ducts, and on the evaporator (cooling coil).

Once the compressor starts, the smell would go away; nothing to worry about.

I too have noticed this off-late in my Creta (after 5 years). However, in my case, this happens only once in the morning during the first start. Post that, even if I keep my car parked for the entire day and restart the blower say in the evening or so, no such smell occurs.
I was a bit apprehensive about this primarily due to the foul smell and also considering the hygienic perspective with regards to the current situation. But going by the comments here, I think this is normal phenomenon seen in slightly older cars. However, can a quick steam cleaning of the A/C vents can help to eliminate this problem?
I was planning to get the interiors done for my car which includes the sanitation / steam cleaning; so was thinking if that'll help to eliminate this smell.

[scorpian]

For the damp smell, turn the heater to max and let it blow hot air for a while that helps in removing all dampness and smell. I have had good success with spraying Ac foam throught the vents and letting it drain from below.

You could try the same. A long pipe helps in pushing the foam right over the coil.

[vigsom]

A cabin air filter helps keep the blower, the evap core and the air path clean

Originally Posted by vigsom

1. by opening the fresh air flap I could access the flap and a portion of the upstream from beneath the blower housing - not easy but not impossible either.
2. cleaned the blower suction and the blower discharge duct too till wherever I could reach using a dry cloth
3. Closed the fresh air flap, and installed the cleaned blower

After over four and a half years, I repated the air path cleaning and inspected the blower, and this is what I found - almost clean blower with negligible dust pick up on the vanes.

I'd last cleaned the cabin air filter about a year ago, and this time although the filter was reasonably clean, I found that a rat had brought in a lot of foreign material and that was deposited just above the fresh air intake flap. When I opened the flap, this fell down through the blower casing, and it was thus cleaned. I then inspected and cleaned the flap through the blower opening and it looked good, except that the sealing foam is now disintegrating. Anyways, that is a task for a later day.

Jun-2020 | Dirty blower before cabin air filter installation


Jun-2020 | Blower cleaned when cabin air filter was installed


Feb-2025 | Blower condition after over 4.5 years - had barely picked up any dust thanks to the cabin air filter and a reasonably clean cabin. Cleaned the blower nevertheless


Foreign material that was deposited by Mr.Rat above the fresh air flap. I always keep the flap closed, but even had the flap been opened accidentally, the stuff would have been blocked by the the cabin air filter


Fresh air path (as seen through the blower casing) after opening the flap and after the foreign material was removed - some dust and a few small leaves were all that needed to be removed


Kick panel below the blower - found clean

[man_of_steel]

Originally Posted by vigsom

Foreign material that was deposited by Mr.Rat above the fresh air flap. I always keep the flap closed, but even had the flap been opened accidentally, the stuff would have been blocked by the the cabin air filter

I too regularly find these collectibles by Mr. Rodent on the cabin air filter. I am considering closing the fresh air duct just neat the wiper motor with a metal mesh or permanently as I do observe some outside smell inside the cabin especially smoke and harsh smells. Have you observed the same?