How to change the Heater Matrix on a 900 Series.
 

I just changed out the Heater Matrix on my 1996 940 with Aircon, and as i did so i took some photo's of most steps, so i thought i'd write a rough guide to doing this job.

It seems a daunting job but is actually not to bad a job just a few fiddly bits. Set aside about 3-4hours for the job.

Most of this would also apply to some 700's particulary those with aircon.

Anyway lets start, please note i took the pictures for this guide as i was reasemmbling it and i've also currently left my carpets out for the time being to allow the underlay foam further time to dry out properly, so thats why the carpets arent pictured.

Starting on the drivers side, remove the front 2 trim covers on the door sill panel and remove the 2 screws. There is also a screw that holds a plastic cover over the seat mechanism, remove this screw and the cover as well.

http://www.chesh.co.uk/matrix/1.jpg

This will then allow you to remove the ECU cover panel in the drivers footwell thats just under the bonnet release.

With that removed you can then undo the three screws that holds the panel just above the pedals.

*******PICTURE REQUIRED HERE******

Moving over to the passenger side, remove the front 2 trim covers on the door sill panel and remove the 2 screws. There is also a screw that holds a plastic cover over the seat mechanism, remove this screw and the cover as well.

http://www.chesh.co.uk/matrix/3.jpg

To remove the panel below the Glovebox, there are 3 trim screws, turn them 90 degrees with a flat head screwdriver and the panel should come off.

http://www.chesh.co.uk/matrix/2.jpg

Remove the 2 screws that hold the side kick panel on and remove the panel.

http://www.chesh.co.uk/matrix/4.jpg

Now hop in the back seats and remove the rear ashtray.

http://www.chesh.co.uk/matrix/5.jpg

With the astray removed, using a flat blade screwdriver prise up the 2 clips at the bottom remove the panel and disconnect the light bulb there. You'll now see the handbrake adjuster.

Moving back to the front of the car, Remove the Front ashtray and the fusebox cover.

http://www.chesh.co.uk/matrix/6.jpg

Then undo the 2 screws below the handbrake and remove the panel, Putting the car in 3rd gear will allow you to get the panel out, unplugging the heat seater switches as you remove it.

http://www.chesh.co.uk/matrix/7.jpg

Now open your centre consol up and pry open the two covers below. One will reveal the OBD connector if your car has one and the other 2 screws. Undo the 2 screws and the whole centre consol should be lifted out the way, you'll have to unhook the obd connector from the centre consol as you lift.

http://www.chesh.co.uk/matrix/8.jpg

With the centre consol removed, and the seats moved as far back as possible, you should now be able to remove both front carpets. The carpets are only tucked up behind the side panels off the transmission tunnel.

With the carpets removed and placed somewhere to dry we now need to remove the Glovebox.

Open the glovebox and prise off the 2 cover plates to gain access to the 2 screws. remove these screws.

http://www.chesh.co.uk/matrix/9.jpg

With those removed, at the bottom of the glovebox are 2 10mm nuts that hold the bottom of the glovebox in. Remove these 2 nuts and lift the glovebox out the way not forgetting to disconect the glovebox light wiring.

http://www.chesh.co.uk/matrix/10.jpg

Ok now onto the the removal of the cubby hole where the cigarrette lighter is. remove the cover and undo the 2 screws, unplug the wiring to the lighter socket and remove the lighter and cubby hole.

http://www.chesh.co.uk/matrix/11.jpg

Now we need to remove the trim around the heater controls. Using a flat blade screwdriver carefully prise if off around the heater trims and then it is then hooked in towards the steering wheel. (i've taken a pic with it off so you can see the clips) Disconnect the wiring to whatever switches you have fitted there.

http://www.chesh.co.uk/matrix/17.jpg

Now remove your Radio/stereo equipment from the panel. I have a aftermarket pioneer unit so with that removed i then had to unclip the adapator plate pictured below for single din size headunits.

http://www.chesh.co.uk/matrix/12.jpg

Now looking into the vacant place where the stereo equipment was there is two screws that hold the radio cubby hole in place. Remove these and the cubby hole.

http://www.chesh.co.uk/matrix/13.jpg

Now we can remove the 2 large panels either side. First remove the 12mm bolt in the footwell on both sides.

http://www.chesh.co.uk/matrix/14.jpg

Then the 2 10mm bolts near the seats on both sides.

http://www.chesh.co.uk/matrix/15.jpg

Then where you have just removed the radio cubby hole you will see another 2 10mm bolts on each side to remove.

http://www.chesh.co.uk/matrix/16.jpg

Now undo the 4 screws that hold the heater control panel and the lower bracket in place. You will have to disconectt all the wiring and vacumm pipes from it.

http://www.chesh.co.uk/matrix/18.jpg

Now press the two clips at the front of the fuse board and lift the fuse board out and move it to one side.

Undo the 3 nuts that bolt the White fuse board base to the transmission tunnell and remove from the car.

******Picture needed*******

You now need to remove the 2 centre vents above the heater panel. Its best to push these out from behind. They are a very tight fit, you will also need to remove the 2 pipes that distribute air across to the vents at either side of the dashboard.

You now need to remove the lower distrbution plastic part that sits on the transmission tunnel. You may need to remove the two pipes that go back underneath the seats to allow you to get it out. I loosened them and then prised them back and managed to slide the distribution unit out.

http://www.chesh.co.uk/matrix/19.jpg

With that now removed, you need to undo the few 7mm bolts that hold the front distributiion panel onto the main air mixing unit. That was what several of the top hoses went to.

http://www.chesh.co.uk/matrix/20.jpg

With it removed you can now see the main air mixing unit.

This is held on with about 10 7mm screws all around the unit. Some are very tricky and you will curse out loud quite a lot gaining access to a few. Specially the ones at the top.

With them all unscrewed. Disconnect the vacumm pipes on the side of the mixing unit, making a note which colour pipe goes to which vacumm switch.

http://www.chesh.co.uk/matrix/21.jpg

You will now be able to pull the entire mixing unit off and see your eventually goal the heater matrix!!!!

http://www.chesh.co.uk/matrix/22.jpg

The matrix is held in by two brackets that are held by some more 7mm screws. Remove these and then open the bonnet.

Undo the 2 hoseclips for the 2 hoses that feed the inlet and outlet of the matrix. Remove the hoses(use clamps if you don't wish to lose all your coolant)

Now you can simply remove the heater matrix.

http://www.chesh.co.uk/matrix/23.jpg

You can then go about fitting your replacement unit.

I ordered a brand new unit from http://www.vehicleheaters.co.uk/menucat.asp?alpha=Volvo

Mine was part number 020528 which according to them is 960 Only but as a late 940 is the same as 960 i can see why, but i did wait until the unit was out so i could measure up and order to be sure. With next day courier delivery the total cost was £75.20 all in. A hell of a lot cheaper than the £400!!!!!! the Volvo dealer wanted for the part.

Here's some pics of the New and old Units side by side.

http://www.chesh.co.uk/matrix/24.jpg

http://www.chesh.co.uk/matrix/25.jpg

The new unit was slightly thinner in core thickness but the endtanks were the correct size so it fitted back in the car a treat.

Refitting is just a reversal of the above stages.

Anyway thats it for now, i'll add the extra pics in when i can take them.

nota bad write up chesh.

Great stuff. I will copy this to Extra Stuff -> Articles later. The first pic - 1.jpg - was missing when I looked at it now.

Bob

Hi - my first post on this forum - a quote for this job in an oxfordshire volvo garage was £1,800 + vat, just shows the value of this post.

cheers

daws

Matrix replacement - tools?
 

Ches740R,
Great post.
Are any special/out of ordinary tools needed?
Thanks again
Ben

Brilliant Chesh. Many thanks
Just shows what a valuable resource this forum is.

Oh. My. God.

I will never, ever again whinge about what a PITA it was to change the matrix in my 850, by comparison it was nothing!!!

Great writeup Chesh.

Cheers,
John

Hi,
What other photos are required for this write-up to be complete??

My 1996 940SE looks to need a new Matrix as well, going by the steam I recently got in my cabin!!

I take it that the same matrix should be Of for me too - same car and year.. :)

Des. . . ;)

Great work Chesh. I think the matrix on my 1993 940 SE TD TIC estate needs changing. What is the best way to print a copy your instructions?
Padrig

Above 1st post, THREAD TOOLS -> Show Printable Version

Hi,
Or as above but use the Download PDF version, this can be saved and printed at a later stage or viewed on screen, thus saving paper.. :)

Des. . . ;)

wow thats amazing piece of dedication, great stuff, really impressed.

it LOOKS like my matrix. but how can i find out for sure...?

snorkel

Hi,
Remove yours and measure/check.
Check with a Dealer as to the part number quoted on the site (link above) for the part.

Des. . . ;)

MY WORD!!!! that's a job and harf! I too am glad the 850 is a bit easier to change.

Great post by the way. Well done. If everyone took a few photos on new jobs then no one would go into a job blind.

Hi,
I plan to do this on my 940 soon and am not looking forward to it too much..

The V90 is worse as the whle dash has to come out I believe.. :speechless-smiley-3

Des. . . ;)

Hi,

Have some extra photos for this which can be added later (when preped correctly! :))..

Comments on the process:
As you have a burst/failed matrix you will have coolant all over the place!
You will need to wash all the carpets and sound proofing, or in some cases replace some.
This presents an ideal opportunity to improve on sound insulation if required.
Everything that comes out will likely need to be washed. This to include pipes, ducts panels etc.. Give everything a good clean.
As above, you are removing things and working in areas covered in coolant. Expect your hands, clothes etc to get covered in coolant/anti-freeze!!!
Have water and soap/cleaner handy to wash your hands..
As this is an issue with a car and components that are WET. . .
DO THIS IN SUMMER!!! Your car will take ages to dry out after you have washed/cleaned the interior!!!

Des. . . ;)

Great writeup! I just did this job over the weekend. Pity I did not come across this earlier.

A question, is there supposed to be any sealant or grommet at the firewall where the hoses from the heater comes out? There's none on mine. Wondering if water or fumes can get it through it. There does seem to be some sort of foam in between the back of the firewall and the front of the heater housing but I don't think that is there to seal it.

Thanks

Hi,

As will be updated in my project threat which includes this process....

Removing the pipes from the engine to the matrix/exchanger pipes:
Easier said than done. They may have been fitted 10+ years ago. Welding has nothing when compared to removong these pipes. Prepaired to be seriously p155ed off!
It helps to remve the lead from the coil to the distributor. Not much, but it helps.
Have a big breaker bar handy!!!

Remove the matrix from the distributor box:
Slides out? No f*****g way!!
The holes through the firewall to accomodate the matrix pipes have a dense foam "grommet!" to prevent movement and vibration as well as seal the engine compartment from the cabin...
These, after the same 10+ years have been double welded into position around the pipes of the matrix!!!
So, while you have a springy movement when trying to pull the matrix out, you have little else.
Use of a breaker bar may help but may also damage the heater box itelf..

Just waiting to find out if there is a part number for these grommet type things....
Before I hack the thing/s to pieces!!! :lol:

Des. . . ;)

des

did you find a part number for the grommets? do you think expanding foam would do the job or even silicon as the bulkhead has been damaged where the pipes go through, (some butcher of a mechanic) and the original grommets would not seal properly. the reason i decided to change it was i found a swamp in the footwell and presumed the matrix but now i have removed it i am not so sure, the one i removed looks like a reconditioned one as it is the original type but painted black and the inside of the housing was dry, i presume the same butcher who damaged the bulkhead did not dry the carpets and sound proofing. i am going to put a new matrix in but want to make sure that there is a good seal at the bulkhead.

gary

Hi,
The "Grommet appears to be a large foam panel stuck to the firewall. You would need to remove the front part of the heater element box to be able to replace it.
I wrapped the pipes from the heat exchanger with the door foam I used to apply to the exchanger itself (to stop rattles).
The pipes from and to the engine fit near flust to the firewall so noise invasion is unlikely...

Maybe heating the pipe from the engine bay may help with their removal...
They appeared pretty well glued/stuck in place... :)

Des. . . ;)

thanks for posting ,I am just starting to a 940 classic p reg heater matrix and although it is slightly differant as it has no aircon all the trim is the same
does the whole unit have to come out to split it ?it has a series of clips round the middle and cant see any other way of getting the matrix out .
any advice would be helpfull ,thanks

Hi,
There is a guide on doing this job in a V90 and there the writer said he used a Stanley knife to separate the box in-situ...

I used a putty knife to initially squeeze through the gunk and then to ease the front of the box away from the rear...
Linky....

So, the whole box doesn't need to come out..

Des. . . ;)