Finally got the old matrix replaced today. As foretold, what a sh*tty job!
Took advice from lots of previous posts and forum wisdom.
A few things that worked for me on this RHD car:
Removal of old matrix
- Clamped both the 22mm heater feed pipes in the engine bay, with flat mole wrenches (jaws padded with some gaffer tape, to prevent hose damage). This cuts down system draining (my coolant was new) and reduces the drain-off at the matrix to about a litre.
- Steering column raised to highest position.
- Parking brake pedal pushed down as far as it will go.
- Unclipped the temperature sensor from the lower matrix pipe.
- After removing the clamping screw for the pipe unions, and sliding the figure-8 block back out of the way, I found the pipes were stuck firmly in the plastic matrix ports, with no apparent separation movement possible of either the matrix, or the pipes! At that point, I had a conversation with John (interrupting his breakfast), who helpfully reassured me that the two alu pipes would move away from their matrix seats, but tended to be held in place by the thick grommet in the firewall. No amount of shoving the pipes produced any movement, so I did the following:
- Clamped the lower pipe lightly with a circular-jaw mole-wrench, pipe protected with duct tape, with the mole jaws about 1.5cm from the plastic port mounding (to avoid risk of distortion to the pipe jointing ridge). This allowed a stout screwdriver to be inserted in the gap, and the joint easily opened up a tad, just enough to allow slow draining of the residual coolant into a funnel and runaway pipe. When drained, repeated with the top pipe. Pipes pulled back to clear, and pushed upwards for extra matrix clearance.
- After removing the two retaining screws, and pushing back the four holding clips, the matrix could be pulled out, but its plastic port moulding firmly hit the steering column mounting bracket (which isn't removable), and no amount of levering or pulling would get it past. Decided to demolish the port moulding, and did so by breaking lumps off it with a mole. When thus shrunk, the matrix could be pulled clear, inflicting plenty of damage to its fins on the way out.
Fitting the new matrix
- Pipe ends cleaned up and solvent cleaned.
To slide the new matrix in, without damage, I found the following worked:
- Lift the two pipes upwards with a short length of timber, stood on the floor. This keeps them out of the way of the forward side of the matrix, preventing damage there.
- I took up Dean's very helpful suggestion of protecting the matrix faces with a thin plastic sheet (I used a pvc document wallet, taped on at each end), but found it still wasn't possible to get the unit in, as it seriously fouled the steering column. I "dealt with" the front edge of the matrix cavity, not by cutting part of it out, but by making three short saw-cuts at right-angles to its long edge. This allowed the edge to be pulled back in sections: the plastic bends without breaking if you do it slowly, and helpfully stays back!
- This allowed the new matrix to be pushed in. The plastic protector sheets were then pulled off.
- !!! At this point, I found that the new Nissens matrix, although absolutely identical in size to the original Valeo unit, refused to fully push home. It was coming up against something very solid. Out it came again, and I found that these units are fitted with a plastic end cover, clipped to the U-pipes at the opposite end to the ports. Very cosmetic, but it hit against the far end of the matrix housing. Cover discarded, and unit re-fitted: sorted. (The OE Valeo unit did not have this cover.)
- Matrix left loose, to enable wriggle, and pipe ends brought down from their wooden perch. Hylomar* and two 21x2mm O-rings fitted to the pipe ends, and inserted into the ports. Followed John's advice about the need to line up pipe-end notches with the (now invisible) half-moon keys, but as nothing had been rotated, it went into place ok. *Would recommend some gasket goo here, not least to provide some lubrication for the joint as it is brought together.
- Circular mole wrench again used on the pipes to help pull them into engagement. The final pull-down done with the clamping plate and its screw, and a gentle squeeze on the plate with the moles. Important to check that the clamping plate remains parallel to the face of the port moulding, and that its positioning lugs don't 'ride up' on the plastic, but sit astride it. Wiggle room needed for this, hence the suggestion to leave the matrix loose in its housing.
- Found that even with the two 2mm O-rings on each pipe, the clamping plate nicely pulled down into position, with a very tiny and equal gap all round. Final tightening of the plate screw closed the gap up, against obvious O-ring pressure.
- Re-fitted the two matrix retaining screws, and bent front-edge housing plastic back into position. Filled the short saw-cuts with a hot-glue gun.
- Removed engine-bay hose-clamping moles, and checked for leaks. Topped up coolant, started engine, and ran up to temp for a bleed. All good.
- Re-attached the temp sensor and trim.
Must say, this job is no fun. Took about three hours, and a good bit of contortion.
Obviously gets easier if done an a regular basis. I have no intention of doing that.
Big thanks to everyone who pitched in advice.
Seasons Greetings!