Here is a step by step of how i replaced my heater matrix on my 1996 mk1 combo van.... unclip gear stick gator, will just unclip around bottom,leave this on the gear stick loose, use a pozi drive screwdriver to unscrew the screw under a small flip off cover in front tray of consul, push it forward until it comes loose them carefully manouver it whilst pushing the gator through the hole so it will remove. A 5.5mm socket to undo five small screw bolts on the bottom of the heater matrix surround,(three on right, two on left.)this will allow the two covers to be slid out into the passenger footwell(left) also there is two other screws holding a side cover,take this off too(drivers side uk) .
Next is removal of the two rubber hoses from heater in bulkhead under the bonnet, a pair of pipe grips will remove the clips, make sure you to slide clips well back, even around corners of hose, this will make pulling hoses off easier, (easy removal of battery and radiator resevoir makes it easier if you have time,) I had to squeeze copper pipes flat to get mine off as they were well stuck, careful not to damage rubber hoses in the process. Now the heater should flip down and out of its recess and jiggle it around untill both copper pipes are free of holes,this should be done from left hand side,(passengerSide..uk) refitting the new one should be the reverse, i would strongly advise fitting a genuine vauxhall heater(£102 on 2/2/2011) as previously to this fitting i had spent four hours fitting a cheap one(£28 inc p&p) from ebay,it was the wrong size and thickness and plastic covers wouldnt fit back together thus causing air from fan to escape resulting in inefficient air coming out of vents,the genuine one had the original sticky foam draught excluder which is also important, it also just popped in easily and i had it back together within an hour,so well worth the extra money...!! take your time as the job is easy, remember a nice pot to pop your screws in to keep them safe, nothing worse than losing screws....!!!!! Good luck...!!!!
John Hembry., February 2011