Knowledge Base

Picture how to on changing the heater matrix the easy way

This is a different way to replace your heater matrix in your MK1. The normal way is to remove the entire dash which takes a good 3 hours, remove the heater matrix slot the new one in then spend another 3 hours putting the dash back together and wondering why you still have a pile of screws.

As it happens after taking my entire dash out the first time round to get to a good condition matrix, I realised the the matrix simply slots into the back of the heater housing with just a couple of retaining screws that hold it in. So i figured that why not cut a hole in the front bulkhead and simply pull out the heater matrix through the bulkhead, slot the new one in and sorted!

Firstly i disconnected the hoses and then marked out where i would need to cut the hole in the front bulkhead.

Then armed with a 4" grinder i set about cutting out the hole. Its a bit tricky in places to do and you need to get the fusebox and vacuum piping out of the way first, but after chewing on a few hot filings the hole was cut. I should point out that because the heater matrix currently in situ was no good i tended to bend the pipes according to where i needed to get the grinder. The metal isn't that thick and the grinder goes through pretty easily. There is some sound deadening and stuff immediately behind the bulkhead but it doesn't seem to catch fire and handily the the heater matrix itself is a good 2-3" behind the bulkhead so there's no way you will damage the housing.

I wouldn't say its the neatest hole tbh and i probably cut it slightly bigger than i needed to, but really i followed the contours of the bulkhead.

And just as i thought undo the two retaining screws, one holding the matrix into the housing and the other around the left pipe and it pulls out. Slot the new one in, connect it up to the pipes and away you go.

In all honesty you could do it in 20mins if you are good. Would say 30-40mins is more realistic only because the hoses are a bit of a pain to get off the pipes.

Refilled the system ran it up to temp and hot air! [Smile]

all i need to do now is make up an ally plate to go over the hole. The crappy plastic trim totally covers it so its not like its highly visible really.

Pics:

as you can see i cut the hole a bit bigger but you can see how far the matrix is behind the bulkhead.

Here you can see the matrix coming out.

The heater matrix housing.

New (well good condition) matrix now in. As can be seen by the heater pipe on the left, you need a bit more cut out that side to allow you to get the matrix in as once it starts going into the housing slot you can't wiggle it that much.