Thread: Remove pipes from heater matrix D4

It’s a common global problem with all of them. At least RHD driver is warm.

I’ve tried to reverse flush unsuccessfully also. Sometimes it works or you need to take a risk on pressure or cleaning solvents.

There’s write ups or videos online on people changing just the core and joining pipes at the crimp. You can dremmel the restricted side access to allow the core to slide out and avoid 3 levels of complex console disassembly. This dremmel attack is covered and out of sight once the upper kick panel is refitted.

Here’s a matrix change guide;

RRSPORT.CO.UK • View topic - 06 4.4 HSE Heater matrix question....

Flush technique but save the pain and join into the pipes at the airbox not firewall

Land Rover LR3 Heater Core Flush - Ep. 7 - YouTube

LR017030 Heater Nissens Repair Kit JEZ500020 JEP500020

Thanks very much. Decisions...

I noticed today once it was back together if I cruised around with the heater off, both in and out pipes on the side of the matrix were hot as hell. Then, turning on the heater to full, a warm blast comes out of the vent replaced very quickly by cool air. Soon after, the inlet pipe on the side of the matrix remains hot and the outlet becomes cool.

Guessing once again but it seems to be a further vote for partial flow through the matrix.

I might cut the pipes, replace the matrix and join the pipes with radiator hose. That will satisfy curiosity at least.

As an alternative is anyone aware of a good guide removing the dash?

At least I now know to remove the console and centre dash easily - from there though it gets a bit wild...steering wheel and stalks, (steering column too?) instrument cluster, frame under the steering column, glove box, the dash itself - anything else?

Originally Posted by Bananas

Thanks very much. Decisions...

I noticed today once it was back together if I cruised around with the heater off, both in and out pipes on the side of the matrix were hot as hell. Then, turning on the heater to full, a warm blast comes out of the vent replaced very quickly by cool air. Soon after, the inlet pipe on the side of the matrix remains hot and the outlet becomes cool.

Guessing once again but it seems to be a further vote for partial flow through the matrix.

I might cut the pipes, replace the matrix and join the pipes with radiator hose. That will satisfy curiosity at least.

As an alternative is anyone aware of a good guide removing the dash?

At least I now know to remove the console and centre dash easily - from there though it gets a bit wild...steering wheel and stalks, (steering column too?) instrument cluster, frame under the steering column, glove box, the dash itself - anything else?

No need - read the matrix change link I provided above. The matrix is accessed pretty easily from the drivers footwell. Remove the drivers seat for additional elbow room.

Thanks PerthDisco. I took a look.

The challenge I have is the matrix in mine has the pipes crimped on to the matrix, not clamped, and the pipes are continuous up to the firewall with no joins. So it seems I need to remove the matrix and pipes as a whole unit, uncrimp the pipes at the base where they join on to the matrix or cut the pipes.

Or wear a jumper.

An otherwise easy job made hard. Perhaps the designers were trying to solve the leaking o-ring problem of clamps and joins, perhaps this assembly was cheaper to make and install. Perhaps they wanted to punish future DIY-ers.

Originally Posted by Bananas

Thanks PerthDisco. I took a look.

The challenge I have is the matrix in mine has the pipes crimped on to the matrix, not clamped, and the pipes are continuous up to the firewall with no joins. So it seems I need to remove the matrix and pipes as a whole unit, uncrimp the pipes at the base where they join on to the matrix or cut the pipes.

Or wear a jumper.

An otherwise easy job made hard. Perhaps the designers were trying to solve the leaking o-ring problem of clamps and joins, perhaps this assembly was cheaper to make and install. Perhaps they wanted to punish future DIY-ers.

Short hose connections sounds plausible with clamps same as what’s in the engine bay.

Anything to avoid dash removal.

I always thought that the crimp connections on these pipes were like those of the EGR pipe work which could be disconnected and reused?

Originally Posted by Bananas

I might cut the pipes, replace the matrix and join the pipes with radiator hose. That will satisfy curiosity at least.

If I was pulling the matrix out I'd do the same thing.

Looking at the coolant routing, the matrix is supplied through the EGR coolers. The EGR coolers have thermostats on their outputs, so there's another thing to look at when considering a reduced coolant flow.

My thought is if the matrix was blocked you'd still be getting warm water out because of the restrictions preventing the rejection of much of the heat. The fact it's taking all the heat from the coolant sounds more like a reduced flow.

The main thermostat also has a bypass valve that works to push as much heat as possible through the core, so it may be worth checking the thermostat also.

As a test you could disconnect the hoses down by the battery box and shove a garden hose in one of them. The flow from that should be severely restricted if it's a blocked matrix. Mine was completely clogged on the passenger side, but still flowed enough not to restrict the hose output. Even with that blocked the return coolant was still warm.

As for the little ratchets, I have several of both of these. The first one is a little ripper with a ratchet on each end. 1/4" drive and 1/4" hex. It also has a very fine ratchet action, so great for restrictive spaces with not a lot of swing.

The Kinchrome set is great too. The ratchet is tiny and fits almost anywhere.

Thanks guys.

@Perthdisco: Oh how I wish they were. I was expecting to see clamps when I first pulled it apart. Take a look at the image in my first post. It shows the 4 point factory crimping. I believe the genuine replacement units are supplied in one piece too: LR015348 - CORE - HEATER | LR Parts

@BradC: Great tips thanks. With the same setup is in this vid; Land Rover LR3 Heater Core Flush - Ep. 7 - YouTube I get good flow through the core, but that could be only through a few of the paths leading to localised heating only of the core which could be quickly dissipated as soon as the fan hits the whole core. All total guesswork. Circulating hot water in this setup makes the inlet, outlet and end cap very hot to touch, but I did not try the fan blowing on it with this setup. With the hoses connected back to the coolant lines (and the coolant vac filled) and coolant at temp after a good fang around the block, both pipes and end cap are very hot to the touch with the heater off (no fan on the matrix) then with the fan on full bore (temp set to HI), the outlet pipe becomes much cooler to touch whereas the inlet pipe stays hot as hell. The cooling of the outlet happens in seconds. It's really quite impressive. That of course does not rule out anything upstream as you suggest. Slow flow on the inlet would probably lead to a similar outcome once the fan starts blowing.

A new twist is that after all the fiddling around on Sunday to check the operation of the lower 2 blend motors, now when I select the centre vents at any fan speed I get air out of only 3 rear facing dash vents. The one to the left of the steering wheel barely utters a fart. Shifting down to the footwell, its a hurricane in both footwells and then shifting up to the vents on top of the dash, there is full flow through all of these vents. Just this one vent refuses. I think this is a new development although I cannot say for certain that it was or was not behaving this way before I started taking bits off. WTF??

I feel I have little to lose. I'm going to bypass the heater this weekend and pry off the crimps so I can remove and dissect the current matrix. I will be crossing my fingers and toes to find it is 90% full of cement. From there I'll decide on whether it's the chop and graft approach with the NISSANS core or the dash out, single piece genuine one in. Since I've had it apart on 2 consecutive weekends already I'm leaning toward the former.

The upside is that in 2 weekends, despite not actually fixing anything and potentially buggered something else, I feel like I've gone from being totally intimidated by the big black plastic engine cover to an apprentice bonafide Land Rover owner:

Google Image Result.jpg

I don't own crocks yet but I am willing to give them a go if they help.

@ BradC
That looks even more useful than the one I got in that you can get it into even tighter spaces.

I'll keep an eye out for one. This is the one I found to be pretty much a sanity saver on Sunday:
11 PIECE RATCHETING OFFSET SCREWDRIVER SET - Trojan Tools