Removing the heater matrix

[Andrew Chua]

Recently i've begin to smell coolant when i get into the truck in the morning and my water level was dropping all the time. Yes, i've temporary bypassed the heater matrix with a pipe to solve the leak for now.

How do i remove the matrix for checking? it looks like the heater box is all riverted up. do i need to drill them out? or is there an easier way?

once out, do i need to do a pressure test? are these matrix repariable?

Thanks

Andrew

[Lars L]

Yes, drilling the rivets is the way forward. Pressure test will show you where it leaks and it can be repaired by soldering. Then it's a matter of pop riveting the case together again.

[Ryan]

Depends - is it this type?

If it is, then the blower box definitely has to come out (the manuals don't tell you this, but there is likely to be a lot of swearing ). You'll need another pair of hands for the two nuts and bolts that go into the footwell. The matrix is held in place by two plates - one top and one bottom - which are held in place by little grub screws. Take both plates off and the matrix should just slide out. And as most manuals point out, refitting is the reverse of removal! Again, there is likely to be a lot of swearing while you try and remember the route the box took when you got it out....

[Andrew Chua]

yes, that's the one in the picture.

so i gather this if i heard your right, figure out how to remove the entire heater box by removing the 2 bolts and nuts that hold it to the bulk head. that means opening up part of the dash board? then proceed to undo the screws to finally get to the matrix. and when done, pray hard that you don't bend anything when you put it back or you'll have a leak again.

[Lars L]

This heater is of a newer variety than mine, so I don't really know how it looks in detail. But by looking at the pic it seems that it's possible to take the matrix out without removing the whole box. What happens if one drills out the rivets around the top of the matrix, can it then be lifted out?

[Retroanaconda]

yes, that's the one in the picture.

so i gather this if i heard your right, figure out how to remove the entire heater box by removing the 2 bolts and nuts that hold it to the bulk head. that means opening up part of the dash board? then proceed to undo the screws to finally get to the matrix. and when done, pray hard that you don't bend anything when you put it back or you'll have a leak again.

There are four bolts holding it in, two at the top which bolt into the bulkhead behind those wires in your picture. I believe they are either threaded or captive, but I didn't have to remove the dashboard.

The bottom two bolts go through to the underside of the top of the passenger footwell.

[sgnas]

You can drill the rivets and take the matrix out.

Drill the front and sides of the hump, then lever the rest to the back (you will not get a drill to the back)

With some jigling you'll get the matrix out.

Loads easier than taking the box out (for a start it's only a one man job this way)

Worth having a go even if you still end up taking the whole lot out as you still need to drill it ou anyway!

EDIT.

Whoops, Ryans pic is of the plastic matrix.

I'm suprised that does not come out if you just undo the screws

[Ryan]

Whoops, Ryans pic is of the plastic matrix.

I'm suprised that does not come out if you just undo the screws

It looks like it should but it didn't. I tried pulling it out from the top, but the plate on the bottom had to come off as well - I can't remember what it was holding onto, but it had to come off and you're only going to do that with the blower box out.

To be honest, if it is the plastic type like mine, you're not going to lose too much time if you try and get the matrix out with the box in situ. Be careful with those grub screws - there's only a couple of threads on them and you don't want to lose them down the back of the blower box!

[Andrew Chua]

okie, worth a try over this weekend. i'll try to unscrew and yank it out before attempting to butcher the entire box.

[stobbie]

I assume the plastic ones are not repairable?

My car was full of steam last week, I had to drive 800 km's back with all windows open and very little vision.....

Is the matrix a dealer part only, or do you think I can order one from paddocks?

I have a few older RHD heaters lying around, could I retrofit the matrix of one of those to my newer LHD heater?

[JimAttrill]

Just a tip - the reason the matrixes get holes in is that the plate that holds the matrix in wears through the matrix itself. Yet another bit of wonderful design. Best is to wrap the plate in lots of insulation tape or similar before refitting or else it will just happen again.

[Rick in Aldershot]

REFITTING THE HEATER UNIT 

Actually, on the military version of the 1987 Defender, you can refit the heater without the assistance of a second pair of hands. 

My 1987 NINETY is ex-military. It has a dummy air intake on the side of the front wing, adjacent to the heater unit. I've often wondered why it is there (simply assuming that Land Rover couldn't be bothered to make a wing without the cutout). But maybe it does have a purpose? If yours doesn't have this cutout, then your Defender may have some other access, but if it does have the cutout it's a godsend. 

Basically, when you're ready to fit or refit the heater unit, you'll put it into place over that wedge-shaped foam rubber sealing gasket and want to very-firmly compress the foam rubber to get the bolts to protrude through into the cab footwell. That's difficult unless there's some way to apply leverage to compress the heater onto its foam gasket.

IF YOU REMOVE THE DUMMY AIR INTAKE, YOU CAN PUT A CROWBAR OR SIMILAR THROUGH THE AIR INTAKE HOLE AND IT'S PERFECTLY LOCATED TO GIVE YOU LEVERAGE ON COMPRESSING THE HEATER AND GASKET ASSEMBLY WHILE YOU REACH AROUND INTO THE FOOTWELL TO POP THOSE RETAINING NUTS ONTO THE BOLT HEADS.

I was "shown" this trick by my haunted ex-military NINETY's friendly "guardian". A long story of how 56KG67's guardian has helped me keep her running, but that story is for another day.

Rick 

 

 

[paime]

i replaced the matrix in my TD5 recently and it's not too bad a job. You've got to take off the air intake under the wing which involves removing the grill, moving the washer bottle out of the way and then removing the retaining bracket that fits to the inner wing. After that you've got the 4 bolts holding it on to the bulkhead which are reachable with a bit of contortion and then you just remove the heater cables and hoses and you're good to go. The matrix itself is easy removed by undoing all the grub screws. Buy a new heater box - bulkhead seal before you start as it'll most likely have fallen to pieces.

[Snagger]

20 hours ago, Rick in Aldershot said:

REFITTING THE HEATER UNIT 

Actually, on the military version of the 1987 Defender, you can refit the heater without the assistance of a second pair of hands. 

My 1987 NINETY is ex-military. It has a dummy air intake on the side of the front wing, adjacent to the heater unit. I've often wondered why it is there (simply assuming that Land Rover couldn't be bothered to make a wing without the cutout). But maybe it does have a purpose? If yours doesn't have this cutout, then your Defender may have some other access, but if it does have the cutout it's a godsend. 

 

 

That side intake is there because somebody fitted a later vehicle wing panel.  NAD 90s and 110s like the MoD had (until the 300Tdi Wolfs) had no side intakes.