Wanted: Heater Matrix & VEM

[aidanmorris]

Hello

My honeymoon period of 480 ownership appears to be well and truly over and after a trouble free few months I now find myself with no blower fan and puddles in both the foot wells, all within the same week.

Not sure if these issues are linked or just an unhappy coincidence!

Anyway having had a good read of posts on this forum I'm pretty convinced the puddles are down to the heater matrix having leaked. Am I right in thinking that this means replace or is it something that can be repaired? If its a replacement does anyone have one I could purchase? And is it an easy job to replace?

As for the blower fan it works fine on AC max but I get nothing on speeds 1-4. I've tested the switch and this seems to work fine so I guess the problem lies within the VEM. Does this tally with others experience? If so I'm guessing it is easier to replace the unit than it is to try and repair? So does anyone have a functioning VEM (aircon version) for sale?

Thanks for reading.

Aidan
1995 480 Celebration

[glasgowjim]

puddles on both sides and the car is parked on the level suggest it is not the matrix . It is easy to know or check for certain if it is the heater matrix.

To check a heater matrix :

1 remove the passenger side carpet section that covers the side of the central tunnel (the part that is at the heater vent about your right ankle on a rh drive car.)

2 it may be possible to just pull it up at the front.
like this

I had earlier replaced the rubber backed foam with carpet
3 pull down the floor carpet as far as possible and feel under the polystyrene foam footrest thats under the carpet.
4 then put your hand under the carpet and the rubber backed foam and check to see if the dampness there is coloured (freom the anti freeze if so the matrix has gone..
If not and its just dirty water then its not your matrix.

So my advice unless your loaded with cash check if you actually need a matrix first.

As for blower check your fuses first before buying a replacement vem.

I am can supply a replacement matrix but would prefer you to check first so you are certain.

Here is a photo of a stripped down 480 cabin with the rubber backed foam in position and in the right hand side a heater matrix lying where I left it after removing from the car.


oh the squarish centre hole is where the pipes go through to the cabin.

this is a photo of a heater matrix with its plastic braket and pipes still in place.


oh here are 2 pics of the vem by the way..



if you still need to get a heater matrix after checking then pm me

[aidanmorris]

Many thanks for the advice Jim

I've been and checked under the carpets and the foam backed mats on both sides. Drivers side was the worst and the fluid was a bit brown but on the passengers side it was clear. In both cases it was slightly greasy to the touch and smelled a bit fishy! I've heard that coolant can smell like that so I hung my nose over the coolant resevoir and this did have a similar smell and is the level was quite a way below the minimum.

This all leads me to think that the matrix is the culprit. Another thing is that having bought the car in May I hadnt used the heater until the other day when I got soaked in the rain and put the heating on full blast to try and dry out. Mind you, having said that, I did end up driving through some serious amounts of standing water that day.....

Am I right in thinking that replacing the matrix involves removing the whole of the dashboard? If so I guess I need to be 100% sure before going down that road.

Any other ways to check?

All advice gratefully received and much appreciated!

Aidan

[glasgowjim]

Hi Aidan

you dont need to remove the dashboard its not a difficult job to do allow an hour nmaybe an hour and a half for the first time. The heater matrix has a constant flow of water through it at all times its just looped into the coolant system. The fan is only exactly that. So the leak will be constant at all times when the system pressurises.

[aidanmorris]

Looks like I'm going to have to bite the bullet and replace the heater matrix and probably the VEM as well (I checked both the blower fan switch and its fuse and these were fine so a dodgy solder joint in the VEM seems the most likley cause)

Jim - are these items that you would have in your treasure trove of spares?

Best regards

Aidan

[glasgowjim]

Hi Alan dont have a vem but I do have a spare heater matrix. will pm you later this evening.

have you checked the fusebox , AND the heater resistor unit ?

worth a quick check before commiting to extra expenditure. Would post up a picture but typing this on daughters netbook.

[aidanmorris]

Hello Jim

How do i check the heater resistor unit?

Will give that a go before getting my soldering iron out and trying to follow the VEM repair "how-to"!

Also can you send me that pm about the heater matrix. Ta

Aidan

[glasgowjim]

The first 2 photos are of the resistor unit and the third is of the location which I have arrowed

[glasgowjim]

Aidan remember you also have an extra relay for the aircon check that as well.


you have a pm

[glasgowjim]

Got the address Aidan

will post out tomorrow (monday) first class.

I have included the connecting pipes and o rings as well this is because although the heater matrix is the same size no matter which model or date of manfacture they are NOT all the same. There are in fact 2 types and they differ by the shape of the inlet plastic. some have 2 lugs which connect into 2 slots in the connecting pipes the other type has no lugs and a shorter insert length.

This is not common knowledge .

So you will have no trouble swopping over use the pipes and matrix I am sending but keep your old pipes , o rings and brass connecting yoke they are handy spares to keep and when you look at the pipes I am sending you will see instantly what I mean.

Remove the pipes and matrix as one : this means draining the radiator system and disconnecting from the rubber pipes from the metal connecting pipes which run into the body.

[balto8]

Hello Aidan.

I'm having the same problem you had in this post in 2012.

When I turn the car on, neither aircon, vent or heating work, no matter if I turn the vent speed selector, but AC max works perfectly. Once I have run about 15-20 kms everything starts working correctly. Tried changing the VEM, didn't work. There's no leak under the carpet so the matrix seems fine.

What was your experience changing the resistor unit? Did it work for you?

Thanks

[glasgowjim]

check fuses .
the heater resistor can be easily removed and a visual inspection done

[balto8]

All fuses and relays double checked.

Seems all left to check should be the resistor. Is it possible that this resistor unit alone is causing all this trouble? Why does it start working after a while? Is it related with the engine vent starting to work once the engine heats? What a poltergeist for God sake!

Thanks Jim, you're allways of big help.

[travelman]

If you have water in both footwells have you checked the drain holes in the well that runs beneath the bonnet with the wiper arms in it and the entry for the air vents to heater.I was having trouble with wet and condensation and purely by chance found the well flooded with water which was sloshing into the vents and on into the car.Cleaned out the gubbins out of the drain at each end and no more problems.Pour some water in and see if it drains out,as rainwater will eventually evaporate from the engine heat and it will look ok.

[Alan 480]

you can easily tell if anti-freeze as it tastes 'sweet' if dabble fingers in it

note that the drains from the well that the wiper motor sits in often fill with leaves as they have a wee non-return flap on them.
i cut these off and since then no problems