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I have noticed a small amount of Antifreeze in the passengers footwell of my TR7 Coupe. I believe this means that the heater matrix is leaking and will need replacing which looks like a nightmare of a job. Has anyone encountered a similar problem?

No my problem was different. The first time I took my current 7 out on the road, & up to a reasonable speed, the ventilation outlets started spitting green water at me. The matrix was leaking into the airflow. In my climate it was an easy fix, I simply bypassed the heater with the cooling water. I did not really find the idea of removing the entire dash all that attractive.

It may be simply the rubber blocks holding the pipes causing your problem, but I think replacing them is still a dash out job.

Hasbeen

Do the whole thing while the dash is out. Separate the contacts and clean each one, clean bulb contacts and test with ohm meter, clean bulb sockets, clean instrument pod contacts including circuit board, lube any moving parts on heater controls. Fix,repair clean anything else you can see or think of under there. Makes pulling the dash more worthwhile and most likely will prevent that electrical problem the will happen in a driving rain squall the will happen next summer.

Hi,

It's unlikely to be the matrix itself but the rubber seals to the matrix. There are 2 mild steel pipes that take the water into and away from the matrix. These are a push fit into the matrix itself, the rubber seals acting as sleeves around the pipes.

The mild steel pipes eventually rust beneath the hardening rubber sleeves breaking the seal and hence the leak. Mine let go with a violent escape of steam enveloping the cabin. A few years ago the fix was to install replacement pipes in stainless steel and new old stock rubber seals. The rubber seals then became unavailable. A new matrix with rigid metal tails is the latest fix.

Unfortunately the matrix is buried in the heater box which in turn needs the whole dashboard and console to be removed. It is a long job that's more fiddly than difficult but if you search the forum there are several contributions including one from me and another from Beans.

Short term for the Summer you can bypass the heater in the engine bay by forming a "u bend" with some copper pipe between the rubber hoses that pass through the bulkhead. I did this successfully for several months.

Hope this helps,

Adam

Over the winter I replaced my ageing matrix but instead of paying over a hundred pounds for the 'updated' version available I used a VW Jetta Heater Matrix no 73940 which came in under thirty pounds and is a direct fit/replacement which has tubes for the pipes to be secured onto no leaky seals involved ! with a modern matrix and works really well.
John

That sounds like a good deal. I did the stainless pipes and new rubber seals before they became unobtainable and paid over twice that. However, I didn't have to drill out all those rivets to replace the matrix as the original stayed in place.

Adam

Thanks for the input - I will bypass the heater for now as suggested - the longer term solution sounds like a winter project.
Thanks also for the tip regarding the VW Jetta matrix.
Cheers

Hi John,
Thanks for your tip re the heater matrix for a VW Jetta. Do you know which model it comes from? I have found on eBay a matrix which seems to cover all Jetta models from 1983 to 1991 with a part no 93701. Do you know if this will fit?
Thanks Trev

Hi,

After many minutes trying to get the ' search thingy ' to do what I want it to do finally found what I was looking for, I could remember moving it in a previous life to the Workshop Section..... have read of this -

viewtopic.php?f=20&t=21010

Cheers John

Hi john,
that's great - thank you.
Cheers
Trevor

Not a difficult job just take your time. Takes lots of pictures as you go otherwise the rebuild will be quite a challenge. Here is one of my images.

Hi Steve,
Thanks for the photo - hopefully a case of "looking worse than it actually is"
Trev

Regarding your ebay part number query I used a local motor factors and the part number I have quoted refers to a 'nissen' manufactured radiator matrix and the other post showing fitting mentions a number of small mods but mine went straight in and a really snug/secure fit.....no messing....which is good ! If you go down this road I have detail from Nissens to show the correct 'IN' and 'Out' ports that should be connected so flow matches the new Matrix.....no venting / bleeding issues then.... just let me know if needed

cheers

John

Hi John,
Yes please if you could - the Nissan option sounds a simpler fit.
Cheers
Trevor

Here is the diagram for the Nissens part hope this works otherwise if you send me a message I will email to you fingers crossed here !