Reason for asking as starting to remove mine to replace heater matrix ,keep searching but no real sound info on removal for my car ,presuming its more like doing a Mk3 which I have done 1 before , mk2 is rather easy compared and have done one of them . Questions related to fixing on the firewall ,I have found 3 by moving the heatshield for the exhaust is that all ? , to bolts under the wipers hold the dash top ,harder to remove the dash than the mk3 for sure as lots of hidden screws and different ways to attach heater vents which so far have been a PITA . Any idea's will be helpful cheers and TIA.
It’s not too bad to do, there are quite a few threads of people changing them, and Rubjonny has a guide, you can do it without removing the heater box, plan for refurbishment of the flaps inside while it’s out. Dash under trays, center console out, remove steering wheel, dash surround, clocks out (fine time to replace the 3 bulbs) then 4 x 8mm head screws 2 either end & 2 just either side of the centre console, 2 10mm head nuts by wiper linkage and the dash will be ready to come out, careful with the wiring as you pull it out. Disconnect the heater hoses now 3 x10mm nuts on the bulkhead for the fan and heater box. Be careful splitting the heater box as the tabs are quite brittle now, clean up the heater box, refoam the flaps and rebuild in the opposite direction It’s 2-3 hrs to do being careful, but I’m sure you can find other stuff to clean up while the dash is out!
I left my upper dash in place. Dash off though is better as you can properly sort out any wiring bodges by the wiring butcher. Screw near plenum air intake; My fine threads in engine bay were rotten on one, what had to do was just unscrew the thread from the plastic body. Then glued it back in later with some perforated stap wrapped over and more hot glue to secure. If you can find an old bicycle spanner or make a thin 19mm spanner this will help a bit. I washed all plastic parts before doing as John stated adding in closed cell foam sheets over duct foil taped flaps. What you may have to deal with;
Thanks guys ,great info ,got the heater unit firewall nuts undone easy ,dash top nuts were a pain but removed the wiper drive and got that one,other side I disconnected the plug of the ignition control unit and sorted that ....easy bit on the dash till I was overwhelmed byy the "hidden screw " design you can't see them but you find them by feel or lying under with a led torch and swearing even more than usual lol. After that I pulled all of the loom fastening off the dash inner ,then found the dash support was in the way on the drivers side so just removed that with loom still attached ,not that hard unlike getting the glovebox out...ran out of idea's but Corrado forum sorted that ,there no delicate way and used brute force as many suggested and will do the mod to make refit and removal easy ,but atlest I got it out . Have the heater box out today (14/10/24 ) and pulled the old matrix and found a huge crack in the plastic flange , recieved a new core with the car and it is correct type ...had it since 2012 and never bothered changing it. Will report further as I go ,cheers .
Heater box flaps done and next job is to replace the foam seals on the blower trunking and vent pipes to the box ,have to do a repair on the heater box as dropped it while working on it on a less than ideal bench ..no big deal as just broke a corner off one of the flanges . Didn't put the foam around the matrix as it was too tight going in as it was ,perhaps slightly bigger that the stock Valeo one but same part number ,recycled the firewall seal is it was in great condition ,hope to get it back in today but need to clean up all the old foam rubbish and clear tools out of the way . Certainly a job I would like finished but the dash top will take a while as I have meters of old wires to remove from the cellphone receiver I found and repair and tidy up previous hacks from previous butcher jobs . Cheers.
Not sure if worth doing, I filled my matrix with cooland and bunged it before locating it in ducting. My thought was less air locks. Its a crappy job to do.
Got the whole assembly in after a bit of a struggle simply because it has to go back dead square to the firewall otherwise it hangs up on the long mounting studs ,once lined up using the fan end as a reference in pops in . The main section of the ducting to vents is distorted where it mounts to the heater box so going to make a thicker seal from some closed cell foam I have and hopefully close the gap up ,hoping the get the matrix hoses on today but appears I need to get the coil out of the way to get the "bastard clips ' on the hoses ,there is certainly not a lot of room to work in this area and the pipes of the matrix don't protr ude that far into the engine bay. In regards to the matrix being prefilled with water ? and didn't do it on the mk3 one I did but let the system get warm and found the system pressure took care forcing the air out of the matrix ,still takes a while however.
Replaced seal for main vent trunking pipe and did a temporary fit to the heater box to check ,as mentioned this area of trunking was very distorted from heat and had shrunk inwards ,the foam strip was simply too thin almost all the way round the edge ,purchased 10mm thick roll and fitted that and got good contact to heater box flange. Did the same to the defroster trunking as the seal is straight on to the cardboard of the inner dash and that was distorted also ,carried out repairs to my dash and fixed various butcher work . Hooked up things to make it run and warmed the engine and checked for air flow which was great ,reved the engine a bit and last of the air in the system released back to header tank ,added a small amount of distilled water ,real pleased with the result ,now the fan is turning nice and smooth with all to foam and crap I removed from it . Cheers.