+1 for removing the left hand instrument cluster bracket - very easy and makes life a lot easier.
The o-rings can be replaced without removing the infamous air duct but is very tricky unless you have small hands and has mostly to be done by feel. If you decide to cut and remove the duct to do the o-rings then access to the blend motor is also much facilitated.
Some advice:
DO NOT switch on the ignition without the instrument cluster connected - a whole new world of pain awaits down that path,
DO NOT ‘muller* the o-ring clamp screw head - drilling out a butchered screw will be ‘challenging’ to say the least. Use plenty of penetrating oil, let it soak properly and, very, very carefully, try to tighten the screw very slightly to just crack it before unscrewing it. Very long (min 12”) shank No2 cross head screwdriver required for this job.
DO NOT overtighten the clamp screw when refitting as you risk cracking the plastic heater matrix.
DO NOT as Richard has already said, externally power the blend motor with the HEVAC unit connected unless you like the sight and smell of the smoke of burning chips!
You do not have to drain the coolant via the main radiator when doing the o-rings. Just crack the clamp screw loose and collect, in a sutiable receptacle, the litre or so of coolant that will drain out before fully undoing the screw.
Not 100% diagnosis but if the coolant is evident at the joint of the heater matrix flange and the collar around the coolant pipes - the joint where the o-rings are - then it’s most probably the o-rings. Get a mirror and a torch and inspect the joint, if the coolant is coming from the slight gap at the joint then it’s almost certainly the o-rings. If there is coolant on the matrix side of its flange then I would suspect the matrix and also the matrix if the joint is nice and dry.
Blowing cold on one side only is a blend motor/flap issue.
Good news and, despite initially going bloody crazy, looks to be a fairly straightforward fix to get the ICE up and running properly. In your original post you referred to an”aftermarket amplifier interface” which seems to match the aftermarket HU to the HK amplifiers. May I enquire what the make/model of this interface unit is?
Yes, they look like the only two options but I wouldn’t mix left to right otherwise the balance from left to right will almost certainly be lost or any significant adjustment of it at the very least.
If the aftermarket interface loom does the necessary balancing to work with the door amps on the LHS without any buzzing etc then I would go for getting a couple of door amps and rewiring to the RHS doors accordingly. I assume the grey/black wire is still present in the driver footwell and this will need a couple of wires put in to switch the door amps on and wiring replicated at the HU end as has been done to switch the LHS amps on unless the aftermarket interface loom already does this. As I understand it the grey/black wire is not a power supply just the on/off signal from the head unit - power to the amps comes via the door outstation.
I believe it was only the Hi Line system that has the 10 pin connector at the back of the radio. If so, this system should have door amps and the sub-woofer amp. The additional two orange wires are the feed for the sub-woofer. The amps are only switched on when commanded via a grey/black wire from a separate 8 pin connector at the back of the radio. I would suspect that this grey/black wire to the right hand side of the vehicle may well be the problem. This grey/black wire feeds to a 6 pin connector behind the kick panel in the driver’s footwell and has two wires from it individually feeding the two door amps. As both doors speakers are not working I would presume that the problem is at this connector of between it and the radio - easy to check which it is with a multimeter.
Perhaps remove the blend motor on the passenger side and check everything it drives moves freely.
All back together now. No coolant leaks, dash to screen trim back in place and all heater flaps moving freely and well greased/lubricated. Blend and distribution motors all fine. Dash went back in OK with the only issues being:
The upper duct on the drivers side - the sliding ‘collar’ just would not fit onto the centre duct. I even tried trial fitting just the collar on its own to see what the problem was. It just doesn’t fit over the central duct. I tried heating it and making it very pliable but it just wouldn’t go on. I can only think that the plastic has shrunk over time - it is exceedingly loose inside the duct it slides in - well it was until the additional foam seal made it snug. It is now about 80% fitted to the central duct and supplemented with lots of tape! Indeed all the ducting joints are now supplemented by plenty of tape!
I had to fabricate a replacement central gasket twixt the dash top and the ducting below. Foam sheet cut to shape and then covered in duct tape top and bottom to give it strength. Gasket fixed to the central ducting with double sided tape. Jobs a good ‘un.
When refitting the glove box release cable I did not locate the release ‘claw’ properly into the lid. I shut the glove box and the ‘claw’ dislocated and I was left with a glove box that wouldn’t open. It’s worse than that because at that point I realised what I had done because, well, I made the same mistake a few years ago when I replaced the damper - doh! At least I knew how to rectify the situation!
Yes, what is that tailgate all about?
They’ve come down in price. At one stage, and this was many years ago, they were well over £300 a throw.
Give the mirror a thorough work out to try and clean the pot tracks and wipers.
If that fails try adjusting the normal position of the mirror just slightly but obviously still acceptable.
Harv wrote:
Isn’t carpet tape 2 sided? I used Gorilla tape, also black and stronger and way longer lasting than regular duct tape.
No, the carpet tape used is single sided used for carpet joins (from underneath obviously), double sided and it would stick the carpet to the underlay - the double sided stuff is used to stick carpet down round the edge when proper gripper is not used. It is very sticky, robust and hard wearing, indeed the downside is getting it off the ducting once it has been in place for some time! It is 10x better than duct tape. I haven’t used Gorilla Tape although I did notice black rolls of it in a shop t’other day - might give it a try when my carpet tape runs out.
O-rings are in. The infamous screw came out sweet as a nut. Old o-rings were decidedly hard and although they came out in one piece one of them just split when I gave it a light squeeze. However, the battery didn’t have enough oomph left after standing around for a couple of weeks or more and my earlier testing to turn the engine over and fire it up so testing delayed. Having put the instruments and air bag back in I didn’t get any faults up except for the usual windows/sun roof not set malarkey. Perhaps the pressure tester was not such a bad idea after all!
mad-as wrote:
when i done my dash removal i taped up all the ducting so it wouldn't rattle or leak. don't forget to check the fans while you have access to them, also remove the evap without disconnecting it of cause, if you like and clean behind it , i didnt do this but there can be lots behind it.
I have to replace all the foam seals on all the ducting as they have all disintegrated to powder/dust - the upside is that removing the residue is fairly easy as it all just rubs off! I also use carpet tape rather than duct tape when sealing the ducts - much stronger and more rigid as it has thread woven into it, and it’s black! Fans, distribution & blend motors already checked and working fine - I am wondering whether to change the latter motors anyway now I’m in there? After nearly 22 years I have to say that everything is surprisingly clean although I am giving it a good ‘going over’ as I don’t plan on doing this again anytime soon - my hands are too big for a lot of the jobs required to remove/replace the dash.
Work on hold at the moment as a) it’s freezing out there and I’m getting old; and b) I am in no rush and can take my time to do things thoroughly.
Pressure test kit is a bit OTT for home DIY leaks - the drop in pressure tells you there is a leak but Mk1 eyeball is still required to determine where it is. I’ve never had much of a problem determining if coolant is leaking and where, and waiting for everything to cool down is not that much of chore - good excuse for an extended tea break! Besides which, the system needs refilling properly with engine running to ensure no air locks, some heat through the heater matrix is a good sign that there is coolant actually flowing through there and will test the O rings with heat as well as pressure.
Thanks Richard, being the cautious type and having suffered from P38 faults being thrown all over the place I ‘jury rigged’ everything back on to test the HEVAC but wondered if I could get away with not connecting everything back up again -it was all a bit precarious without the dash in place! Passenger air bag isn’t a problem as it’s frame is still there.
Thread update - dash is out. I finally decided to remove it as there was water ingress on the driver side (onto the horizontal kick panel under the dash to the right of the steering column) and, from externally, it didn’t look like it was coming from the pollen filter housings. Good news is that it’s not the windscreen so must be pollen filter housings unless anyone else can suggest where it might be from?
All HEVAC motors and flaps are working well with none of the groaning I heard prior to dash removal. Any suggestions or was it just the onset of cold weather?
All duct sealing has completely disintegrated particularly the windscreen vents seal to the ducting underneath - just powder now and one bit of it was never positioned properly from factory build - it had been pushed into the main ducting on its rear edge!
The errant dash to screen rubber trim has been refitted into position - it’s clear from the way this needs to be rolled/folded round the dash from below that fixing it in-situ is impossible - well impossible with my fat fingers.
All wiring and connectors behind both the left and right kick panels are in very good condition so that’s a bonus.
Next job is to renew the heater matrix O rings now I have really good access. Question is I will want to test them out for any leakage before re-installing the dash by running the engine up to temperature. I know I will have to temporarily reconnect the instrument binnacle but are there any other units that should be reconnected before I switch on the ignition and fire the engine up.
I fitted the zebra connector a couple of years ago and all was fine. Last winter, however, the display started to lose a few segments but recovered quickly as the car warmed up. Unfortunately, the problem gradually worsened so a month or so ago I decided to disassemble the HEVAC unit to see what could be done. I discovered two problems:
The two screws immediately under the display unit that holds the internals all together and provide most of the clamping force for the connector were loose and the threads in the plastic housing had stripped - I was probably a bit overzealous in the previous reassembly in trying to ensure a good contact. The application of a few drops of fibreglass resin into the holes sorted that problem out.
The display connection strips on the board (not the display itself) were very discoloured. They had been cleaned when I first installed the zebra connector but I was very gentle. Probably too gentle. This time I used a plastic scraper (a clean spare small glue spreader in my case - definitely non metallic) to firmly but carefully scrape away all the discolouration using contact cleaner as ‘lubrication’. This took some time to get all the strips looking brand new. I also carefully recleaned the contacts on the screen itself for good measure even though they looked OK.
Once reassembled the HEVAC display has been back to rude health at all times . . . . . so far.
I’ve never had much success using adhesives as keeping the seal in the correct position whilst the adhesive cures has always proved tricky to impossible. I now use double sided tape but it has to be the 3M variety which does stick instantly and holds really well - have to spend a little time making sure both surfaces are absolutely clean though.
May drift even further! For the first time I can hear the blend motors struggling - they currently still do the business but are now making their presence clearly known. The front trim on the dash (twixt dash and windscreen) has also come adrift on the driver’s side. These together with the O ring leakage now has me considering complete dash removal to ‘cure’ all these ills. This may also escalate to a change of the heater matrix itself to remove the O ring problem once and for all.
And plenty of anti-seize on the threads of the new sensors (they came with plenty already applied) and not overtightening the crush washer will make them easy to remove next time . . . hopefully . . . if there is a next time . . . who am I kidding, of course there will be a next time - this is a P38!