Aircon clean out / pollen filter

conaero

Forum Owner
Messages
32,467
As the better weather starts to come round again, be prepared this year and not have water dripping on your open toes in you Jesus creepers, clean out your pollen filter and aircon drain:

You will need a new pollen filter (DESMO B838 £20-40) as you old one will be soaked and not usable.The drain tube that goes throught the transmission tunnel just by the drivers left foot gets blocked and then the water backs up into the matrix, then the pollen filter and then over to the blower motor on the passenger side, leaking out of the seals in the motor or where the wiring for the fan unit is.

Quick Fix
There is a big black drain tube that runs from the middle of the tunnel top to where the foot rest is for your left leg. Remove the tube by pulling it up and out and the unit should dispense all the water on to the carpet, so have a cloth ready. Where the tube entered the tunnel there is a square rubber surround with a funnel end that goes to the outside of the car, remove that and you will probably find its blocked where it narrows at the bottom. This is to stop stuff from coming back into the car from outside. I cut the end off mine to stop it blocking again, much easier. Replace the square funnel, check the rubber tube is not blocked by running the fans (in econ mode) and you should be able to feel air pressure thought the tube. If all well then refit the drain hose otherwise check that the tube is not kinked or blocked.

If water has got as far as the passenger foot well then you are going to need to clean everything out and probably a good idea anyway as the original blockage looks to be caused by a small build up of decaying matter from either the internal vents or the outside vent. First off make sure you have a replacement pollen filter DESMO B838 although most motor factors have them listed from the cars make and model. Remove the middle wiper arm with a nut and a small amount of prying. Remove the scuttle panel (lots of screws) only unscrew the top screws a few turns as they have square block connectors that should pull out and will fall off it you unscrew too much. The scuttle panel hooks under the windscreen so gently ease it out. Disconnect the washer jets or just place it out the way. There is an additional panel with four screws on the passenger side that revels a mess covering the air intake for the fan, remove all this and clean out the leaves and vac out fan motor to make sure there is no leaves in their. Water was visible in the bottom of the fan motor. Next remove the wiper arm motor (two bolts) so that you can move it out of the way enough to access the centre panel. Remove the Allen key bolts in the centre panel and the cover which will then allow you to access the pollen filter. The pollen filter is held in place with two bolts and then you need to move the wiper arms in order to get the filter out. Mine was soaked and again full of water and leaves. Clean all of that out (we used a Henry wet and dry vac with a thin hose attachment) and fit the new pollen filter. We also ran a blower into the fan motor area to dry out the area before refitting everything in reverse.


Shot of car once you have removed the wiper cover and intake grill. The metal cover for the pollen filter can be seen on the left of the photo.


Shot looking down inside the fan motor where water can been seen collected in the base of the unit. Left there and it will rot the electrics for the car.


Shot of engine bay with pollen filter cover removed, note the removal of the wiper motor required to allow you to lift out the pollen filter.


Shot of inside the pollen filter housing, swimming in water and leaves that have worked there way past the fan motor.


Shot of the large black drain tube easily accessed by the drivers left leg foot rest. Check out the wiring loom and the silver a/c collant pipes that can sometimes get condensation on them.


Shot shows the drain tube working back towards the centre of the a/c unit and the circular, remove the drain tube from the rubber surround and then remove the surround.


Shot of drain tube removed and blocked with gunge and the famous words "Made in Italy"


Shot of drain tube cleaned and modified by removing the restrictive end.


Removing all these parts and cleaning out all areas should be a mandatory thing for all owners to do to prevent future issues.

Hopefully this should be enough to help people work it through.
 
Last edited:

Klive

Centenary Club
Messages
721
Great post Conaero. This type of thing should have it's own section.
 

Parisien

Member
Messages
34,914
Yup, good useful stuff......indeed invaluable!

Don't we have a fixes section already......combine the thread?


P
 

Paul L

Centenary Club
Messages
471
Hi Matt,

Just to let you know I used the above on the 3200 of mine to be sure of no leaks and blockages causing the condensation. A clean bill of health for me,

Many thanks for the posting, extremely useful!
 

jamesc69

Junior Member
Messages
494
I followed the above detailed instructions and cleared what seems like gallons of dirty water and leaves.
No more wet passinger carpet, and best of all no labour charges !
what a fantastic resource sportmaserati forum is!!
Thanks guys
 

Parisien

Member
Messages
34,914
Good stuff.....as I live at the back of a small wood, I suspect I have 4.5 kilos of leaf litter accumulated this year...must get it done next week!

Cheers James for the reminder...and Conaero for getting his hands dirty!


P
 

BennyD

Sea Urchin Pate
Messages
14,379
Matt, can't you just take out the rubber drain tube and surround (from underneath) to clear it out/modify it? That would save a fair bit of dismantling "up top".
 

conaero

Forum Owner
Messages
32,467
You can indeed Benny but it backs up so much all the way to the pollen filter and once that is wet it has to come out as that will leak too.

So best to spend an afternoon and do the job properly.
 

2b1ask1

Centenary Club
Messages
18,184
Guess what I'm doing tomorrow....

Driving mine today in Jesus creepers and got a wet foot! Commented to Jeanette who said yes I had that last week..... Duh!!! Air-con is struggling at the moment so It's a fair bet it is going to be full of water; I'll report back what I find... One less job to be done at the service now!
 

dunnah01

Member
Messages
648
It may be worth reading for any error codes if the air con is not quite right. Turn ignition on but don't start the engine, after a couple of seconds push the 'recirc' and 'econ' buttons at the same time - you should see AA appear on the dash readout where you normally see the outside air temp. If any arrors are stored then a number will eventually appear which indicates the error - if 00 appears then there are no faults stored so happy days.
 

2b1ask1

Centenary Club
Messages
18,184
Ok so Scuttle off (centre wiper first); must add to Matt's excelent commentary at the head of this thread that only the middle three top scres are retaining finger clips and should each be undone only 3 or 4 turns.

Took the guard off the recirc/fresh air intake and removed half a pigeion (got that one last week!) and much of Thetford forest!!!, removed the two bolts holding the wiper motor and the cover of the filter, the retaining screws and lifted out the filter..... BONE DRY!!!!! Also very dirty so not changed for a very long time!

I fashioned an extension tube for the vacuum out of some 22mm Hep2o I had laying aboutand cleaned out the rest of Thetford forrest including a near complete female stag beetle! Cleared out rghe corners of the scuttle bay and multiple drains.

moved inside and removed the carpet and accessed the supected blocked drain to find it too was clear! I guess what I have is just condensation on the pipes...

Couldn't get a replacement filter on a sunday so I banged out the old one, & blew the dust back out with my airline and reassembled (I'll get one in the week).

Spent the rest of the day washing away the detritus of the last couple of months and waxing... took it for a blast (with issues) but got a good feeling now!
 

rossyl

Member
Messages
3,273
moved inside and removed the carpet and accessed the supected blocked drain to find it too was clear!
Just to check, does the carpet come away quite easily? I've just been out to try and have a look at this but obviously it's rather dark. Goes the plastic foot guard come away, or should I be looking above this?

Thanks
R
 

2b1ask1

Centenary Club
Messages
18,184
Rossyl, it is actually a very easy removal, couple of self tapping cross head screws I recall but then it is just slipping it forward enough to clear the centre console and the drain pipe is easily spotted and you can wriggle it out with a couple of fingers round it! kneeling beside the drivers seat on the ground gives very good access, not more than a 5 min job.