BX TZD heating and cooling project

[tlampre]

Hi, this was the weekend to get going on a fairly involved job with my '91 TZD turbo. I've been stockpiling parts off eBay and finally have all the most needed bits. The car will be off the road for a couple of weeks while I do the first phase:

- Replace the coolant hoses that run behind the engine, as well as a couple of others.
- Start installing air conditioning by replacing the heater box with one that has an evaporator installed plus the dash controls.
- Install new heater matrix and tap while I'm at it.
- Repair dash while it's out, mainly the demister vent that has cracked.
- Add some extra sound insulation behind the dash.
- Replace the doseur valve.

I have three weekends to get the car back together before I go interstate for Xmas. Next year I intend to finish the air con part of it.

Yesterday was focused on pulling things out of the engine bay.

The hoses are well hidden, you can just see them lurking behind the turbo ducting.



Even with all the clobber out of the way it's still a tight fit. Enough to get hand down but no room to maneuver.



I put a jack under the lower engine mount and removed the top mount, then used a wooden beam to tilt the motor forward. I wedged a long socket in to keep it there. Still not a fantastic amount of space but a whole lot better than before.



Now to get the hoses out. The long one that leads to expansion bottle is the easiest to get at. There was no room to get a screwdriver on the clamp and it was then that I discovered I had lost my 7mm spanner. Not enough space for even my small ratchet but I found I could turn a socket with my fingers.



The hose was well and truly on the way out. Very soft and cracking on the end.



Next up was the short hose that goes to the heater. The heater end was easy enough to get off, but the other was held by a Jesus clamp.



The Jesus clamp, a close relative to bastard bolt, is a clamp that evokes the words, "Oh Jesus..." when sighted in a cramped space. I'm sure they are very quick to install on the production line as they work a lot like zip ties but are cows of things to get off. I'm sure there is a special tool, I imagine a pincer like thing that gets under the clip and pops it off. But being able imagine a tool doesn't make it appear in my toolbox. A screwdriver under the clip can eventually make them loosen, but there was no way to get one into the confined space.

After a few false starts, I was able to hammer a screwdriver under the band using along drift. The driver had a hex shaped handle and using a large socket and an extension bar I could twist it until the band snapped. That only took about 45 minutes.

Then came the longer heater hose. Oh no, another Jesus clamp!



Fortunately, as the heater box was coming out later, I didn't need to get it off. I just cut the hose off at the pipe and moved to the other end, which didn't look too flash.



If the other hose was bad, this one was a disaster waiting to happen. The outer rubber was gone, the fabric reinforcement was all broken and just the thinnest bit of rubber was all that was keeping the coolant in.



So all the hoses are out and the doseur looking temptingly accessible but that will have to wait. I did get the blower out before having to pack it in.

Next up is getting the dash and heater box out.

[BX Bandit]

Nice work! I like the Jesus Clamp thing! I would of called them Fuck Clamps cos I always say Oh Fuck when I see them

Those pipes are fibre glassed aren't they? You'll be itching a bit after that! I had one burst on the Valver!! Luckily I wasn't far from home so I managed to bodge a fix to get me there!

Keep us posted, especially on the a/c installation. I've not done one, but there are 1 or 2 on here that have so they may be able to help!

[tlampre]

Yeah, I think it's fiberglass inside, with stainless steel on the outside. I had steel 'cactus prickles' in the back of my hands the next day.

Sunday's objective was to get the dash and heater box out, and cut the holes in the firewall. I didn't manage the last step on Sunday but made a start on it this evening.

There isn't much to say about removing the dash. It's more tedious than anything. It can be made more complicated by electricians installing wires that wrap around things. I had to cut a couple of wires that will need plugs installed before I reassemble.

The TZD has more soundproofing than my other BX's. There might not be much room for improvement. The bitumen has the locations of the holes molded in.



They tear out easily, I only needed the knife to clean up the edges.



The matching hole is also easily removed inside the engine bay.



I did a dry run with the recirculation boxes to locate where the holes would be needed. Cutting the wrong place would be a very bad thing.



I also noted that the new blower on the drivers side had nothing to fasten it down so some work will be needed there later on.



The sound proofing over the recirc holes just peeled straight out again. This is the driver side.



Ditto on the passenger side. I'm using a nibbler to cut the hole as I don't have mains power available. I didn't finish that hole as it was really a case of making sure the nibbler would hack it. Fortunately the metal is quite soft. If it's a worry getting the holes the right size, I think they could be made quite bit undersized without affecting air flow.



I did make proper attempt on the hole for the air con lines. Here is it started. I have used the nibbler for a lot of jobs. It''s slow but can get excellent results with practice. A hole saw and a power drill would be a lot quicker though.



And 45 minutes later, the finished hole.



The grommet fit perfectly!



That was about 1.5 hours work, all up. It's going to be a slog to get this all done in the time I have. The priority is to get the heater box back in so that I can reconnect the hoses and get the engine back on its mount. I'll be having to do a bit each evening if I'm to do everything I hope to.

I have the loom from a 16v draped over my living room floor at the moment. One thing that I would recommend is to have the donor car along side where you can pull bits off as needed and know where they should go.

[mat_fenwick]

Keep up the good work! I was lucky when I did mine that all the holes were already there, just blanked off with bonded in plates.
If you don't know whether the system works it might be an idea to test it for leaks before fitting - you'd be fairly cheesed off if it turned out the evaporator had a leak after you put the dash back in!
I have a PDF wiring diagram of the A/C system if that's any use, bearing in mind there are apparently a number of variations of it.

[DLM]

That's a good set of pix - consgratulations. The aircon job certainly is a bit long-winded to do: my experience of it comes from removing the dash from the aircon donor car I was driving at the time, helping with some removal of parts, and watching some of it being transplanted into the car I now own.

I'm quite surprised to see no pre-cuts and blanking plates: many TZDs over here past a certain date seem to have the aircon shell.

[tlampre]

I'm not too concerned about the wiring just yet. I've identified the part that operates the recirc flaps and will install that now as it goes through the top grommet into the plenum. Trying to put that through with the dash still in would be a pain. The other wiring goes through the normal grommet in the passenger foot well so isn't urgent.

I did originally intend to send the evaporator off for testing but things have been brought forward and I didn't have time. Initially I was only going to do the heater hoses and doseur but I thought it would be better to do the heater box as well as it gave more options if I had trouble getting the hoses off. (Like smashing the pipe if things got really bad.)

And I doubt that the evaporator will have a leak as it's all copper tubing:



The aluminium ones can perforate but copper is much better. It's a fearsome thing. I overhauled the air con in my Falcon wagon and the evaporator in that was 3/4 the area and 1/2 the thickness to cool around double the volume. Little wonder the BX has such a reputation for ice-cold air con!

The TX valve will be replaced, they are one of the most common source of leaks. The original is an Eaton part number 329-439 for r134a refrigerant. I got an equivalent part from my local Repco auto store. For Australian readers, it's part number TXX3439 and cost $105. Here it is with the old one to the left of it.



A new heater core is also going in. The black foam on the side is needed to stop it rattling. It didn't come with it, though, I was lucky enough to have some lying around



Once thing I noticed about the old heater box was that it had a third bowden cable that operated a flap to close the intake when the heater control was turned fully on.



I always wondered why the final turn of the knob felt funny. I thought the tap was jamming. I guess this is a feature to stop the outside air coming in when it's really, really cold?

Speaking of the tap, I scored a brand new one off eBay. I almost missed these:



They are the seals and need to be removed from the old tap. They can be prised out with a small screwdriver via some slots provided.



I missed those at first and was swearing at how hard it was to get them out without damaging them. Lack of brain power has been a bit of a problem lately. I forgot to get a set of r134a o-rings until the last minute. They still haven't arrived. If they don't turn up by Friday I'll be in for a long walk to the auto shop to see if they can match the old ones.

And to top it off, I want to replace the temperature sensor that is in the evaporator with a new one. They are just 4.7K thermistors and I had a small bag of about 5. Do you think I can find them? I dragged myself to the electronics store at lunch time only to find they were out of stock. So I've ordered some by mail with next day shipping. $15 for a 95 cent part.

[tlampre]

There hasn't been much time to post last week. I've been up until midnight most nights finishing the heater box and repairing the dash. I'll post a few pics about that later, but skip forward to Saturday now where I was putting the heater and hoses back in.

First up, I wanted to replace the doseur valve. My regulator cycle time is about 45 seconds. Not stellar, but not awful either. I almost piked on on the job because I was so tired but I'll never have such good access as this again and it bugs me to have a brand new valve sitting the spares box.



Removal was pretty easy. Unlike my FDV, that had one line rusted in so badly it needed to be held in a vice and pair of Stillsons used to get it out. The lines to the doseur all unscrewed with no force, with some I could use my fingers.

The only hard one to get at is the lower return line but the hose is long and flexible and can be done after the valve is lifted up. So I got to this stage in a jiffy:



The mounting boss slides off and the studs I could undo with my hands to transfer to the new valve.

Reinstalling is again straightforward, the only wrinkle being that no matter how many times I wiped my hands they'd be covered in LHM again in no time and I nearly lost my grip and dropped the thing.

Once in, put the nuts on the studs to stop it falling back out but don't tighten them. Being able to move it around makes getting the lower HP line in easier. The lower return line was connected prior to putting the valve back.

Of course, this was all too easy. When it came time to tighten up the lower HP line the thread wouldn't start. HP fittings usually do up easily if everything is lined up square, but if not they need to be jiggled a bit until the thread catches. Nearly an hour later I had taken the valve out twice just to convince myself the thread was actually OK. On the second occasion I was tempted to hurl the thing down the end of the street. Then, suddenly it went in. The thread was very stiff, as were the other HP lines.

Now came the heater box. Who's bright idea was this?



The splayed ends of the pipes means the grommet has to be pushed on with considerable force. Parallel pipes, please! Maybe I was just grumpy after the doseur hassles. Oh, the grommet in the picture is upside down. The longer part points downward, as I discovered when it was half in.

Getting the heater box in is a matter of patience and juggling. Make sure none of the wiring is snagged. It should either sit on the floor or be draped over the top.

My beautiful job of cutting the hole for the air con pipes meant the grommet went in snug and easy, thank goodness, as the heater pipes were not as cooperative. On the first shove, the studs on the top of the box went straight into their holes but I wasn't ready for that and slipped as I reached for something to wedge underneath so I could go around to the plenum and put the nuts on. It took a while before I could repeat the trick. Not that it mattered, as I had to take it back out when I realised the grommet was upside down. Getting the grommet in boiled down to brute force. Just make sure the edges are in the hole and not turned outwards and shove hard.

And here it is:



That grey stuff with glue on it is extra sound proofing. It's Barium filled vinyl that can be purchased from electronics stores that sell materials for DIY speaker boxes. It's soft and very heavy. Possibly overkill after seeing the sound proofing the factory put in, but the stuff was paid for and I figured it couldn't hurt.

I will say that getting the thing in was easier than expected, based on previous cars, so I made up some of the time wasted on the doseur.

The two air con pipes are easy enough to get at when the time comes to connect the piping, which won't be until next year. I've since wrapped some plastic over the ends with cable ties to keep dirt and moisture out.



Now, finally, to get the hoses installed. Here they are, except for one that I hope to receive tonight.

At this point, a word of thanks is in order to Michael (m_2975) who has helped me track down correct part numbers and even the last hose. I had given up on that one, the best I managed was that "there is one at a dealership in Kent but they don't do mail order". Michael has sourced that one for me and an expensive thing it is is, too. But mine has begun to split and needs to be replaced. So many thanks to Michael for going beyond the call of duty.



The braided ones go behind the engine. And the braiding is indeed fibreglass, not stainless steel like I first thought. The end of the braid is held by a plastic collar:



In the above picture some glue is visible that holds the braid securely and stops the collar sliding. The other hoses didn't have that and while wrestling to get them on I pushed the collar down allowing the frayed ends to be exposed. It's not the end of the world, but getting the braid back under the collar is difficult. If neatness is important, inspect your hoses and squirt a bit of glue under if they don't already have it.

The hoses are easiest put on in the following order.

Start with the small hose. That goes on the inboard outlet on the engine to the lower heater pipe. The ends are of different sizes, the wider one goes on the engine so it's impossible to get it around the wrong way.

Then the middle length hose goes on the upper heater pipe, along the firewall and onto the outlet behind the thermostat. Don't take it through the strap on the firewall (like I did).

Then the long hose goes on the outboard outlet of the engine, around the firewall through the strap and connects to the expansion bottle.

In the end, the medium hose coils around the longer one slightly, holding them both as far away from the turbo as possible. (Which isn't very far).



All this is hard on the hands. Apart from the little bits of glass that stay stuck in the skin for a day I have scratches and cuts all over my left hand half way up to the elbow. This is very hard to avoid as the space is so confined and even with pre-softened ends the hoses need a fair bit of force to push and twist into place.

[toddao]

Very interesting and impressive work there. Don't think I'll be installing A/C any day soon around here - it's bloody artic plus I don't think the Mk.1's had any option! Am I wrong?

Nice new doseur, mine looks like a rusty old bomb and is about as effective!

Tell Michael (m_2975) that he really should drop by the forum again. I tried to encourage him..

[tlampre]

All the the Australian delivered cars had air, including the Mk1's. I never had the dash out of my 16TRS, but from looking at the manuals the heater box design stayed the same. The controls would be different, of course. But they could be sourced from Oz quite cheaply if someone is wrecking a car.

[maxgreenwood]

tiampre, this is a great write up of the jobs. Gives me the confidence to replace the other two braided ones when i need to. I had the garage replace the medium one behind the engine and i just replaced that small one from the therom housing this evening. They said the other two braided ones looked ok but who knows when they're going to go as they can deteriorate internally.
Is the other non braided one the mid rad to oil cooler hose? I'm picking that one up later this week along with the big bottom radiator hose to replace.

[BX Bandit]

One thing I noticed on the TGD Turbo I'm scrapping is that some of the 'braiding' had worn off on one of the bends, as if it had been rubbing somewhere. Worth making sure they are all secured nicley!

Nice work though tlampre!

[tlampre]

Hi Max, yes, the 'S' shaped one at the top of pic goes to the oil cooler. I haven't fitted that yet, nor the small one from the thermostat to the pipe. I set myself a strict deadline on Sunday to stop on the engine bay and start on reinstalling the dash. I just managed to get the dash in before sunset.

We are having some unseasonal weather now, both afternoons have been cloudy and it's raining tonight so trying to get anything done after work is hard due to the lack of light. I should be able to put some water in tomorrow and bleed it all. If there are no leaks I'll drain it and put the proper coolant in.

[maxgreenwood]

Did the small thermo housing hose last night. Its amazing how long little jobs like that can take. It had a "Jesus" clip on it which i had to hacksaw through. Filled up and bled this morning. Now.. to get my heater fan working...
Well done with the air-con, that seems but a distant luxury for me and thankfully not really required in the atlantic beaten emerald isle!

[tlampre]

Cool weather certainly reduces the need for air-con, but I still like it for demisting the windows quickly. None of my BX's have had working air. I tried getting my TRi regassed but when I came back to collect it I was told, "Couldn't regas it, your switch is broken." I tried to explain the it wasn't a switch, but a rheostat, but they just kept saying, "Get your switch fixed and we'll squirt some gas in for ya". Such is the effect these cars have on many mechanics here in Australia.

The weather cleared overnight so I was up at 6:30 this morning to deal with the rest of the hoses before work. I had partially replaced this one last night.



This is a bleed hose that connects the top of the radiator and thermostat housing to one of the outlets on the expansion bottle. This the hose that Michael sourced for me. As it turned out, the one he found was not for a diesel but a 16v. Nevertheless, it was a suitable fit. It needed to go across the front of the engine instead of along the top of the radiator like the old one.



As you can see, it comes with yet another bleed point as a bonus. The old hose seemed fine until I had to remove the radiator. The end of the hose was hard and began to split after I disturbed it. It was the most expensive one to replace, too, at AU$220, or about 98 pounds at current exchange rates. Ouch. At least it was easy to get on and off.

Next up was the oil cooler hose, the far end of which is buried underneath cables and hoses:



Be careful to make sure it's the right one, as there is another of similar size right next to it. It had a Jesus clamp, but I was able to loosen the clip with a screwdriver as it was aligned in the right spot.

I noticed the top elbow was in contact with an electrical connector coming out of the green plug. (Oil pressure switch?). When I put the new hose on I pushed it down hard so that it wasn't touching.

The end of the looked like this:



This was facing towards the block and invisible. The rest of the hose looked fine.

Finally, it was time for the little fella.



Perhaps the picture is blurred because I was shaking with excitement at the prospect of finally being finished with all these hoses? I was shaking my fist at it later on. Getting it off was easy enough, rip the Jesus clamp off with a screwdriver (getting good at it by now) and then cutting the hose into chunks and peeling it off.

My first mistake was following the orientation of the old hose. The factory got it wrong. It wouldn't have made a big difference on the assembly line, but the thermostat end is slightly larger than the pipe end. They would have put the hose on the thermostat before bolting it on with the hose sliding onto the pipe in one go. But that difference in size was huge when the thermostat housing is already in place due to the awkward access. I couldn't get the hose on and it wasn't until I measured things I realised the problem

So, fat end of hose goes on the thermostat housing!

Once I had that sorted, I found it easiest to put the hose on the pipe first and push it down as fast as possible so that the other end can be squeezed under the thermostat outlet. Then I slid it back off the pipe and up onto the outlet. It took a bit of muscle, but I got it on eventually.

Removing the thermostat housing might also be an easier way of doing it.

Filled it up with water and started the engine for the first time in two weeks. Started first time. I waited in vain for the suspension to rise before remembering to retighten the pressure release screw. Did that, and everything worked. Bled the system and check a few hours later. The concrete was dry, no water or LHM leaks.

Still have to bleed the brakes, put proper coolant in and finish some interior bits, but it looks like the operation is a success as far as the hoses are concerned.

[tlampre]

Jumping back to the week before last, I'll show what I did to prepare the heater box part of the air con.

I bought this full r134a conversion kit off of eBay.



This is serious overkill, there are enough o-rings to fix a dozen cars but it was easier than fronting up at my local car parts place with a handful of old o-rings looking for replacements. It also has new valves and a tool to remove them. The can behind the box is the same oil that goes into the system and is used to lubricate the o-rings. It's ridiculously expensive but you might be able to get just a little for nothing if you are on good terms with a mechanic. You only need a thimble full.

The o-rings go on each pipe after being smeared with oil.



And then the whole lot is screwed together.



It needs to be tight but not gorilla tight. The o-rings will do the work, if overtightened they will distort and leak. Just like the hydraulic seals.

The sensor is just a 4.7K-ohm thermistor. Here is is next to the old one.



I hate soldering. Never got the hang of it. I noticed when I stripped the ends of the cable that it had a dull whitish look. It's the type of wire that won't take solder. So I dug out another bit of wire and used that instead.

After soldering it on and using some shrink tube to cover the wire I epoxied the lot onto the old sensor.



Then it poked back into the evaporator and the new wires crimped on to the old ones.



And that completed the heater box assembly.

The car is back on the road now and I'm feeling a bit flat. Although I know it should be more reliable now with all those new hoses the only visible thing I have to show for it are some ornamental switches on the front panel that don't do anything yet.

And, the engine develops a very rough note above 2000 rpm. I'm thinking the engine mounts, that have about 270K km's on them, may have been damaged a bit by the weight of the engine twisting them for two weeks. So the car is booked in tomorrow to get all three mounts replaced. Hopefully that will remove the harshness. Bit off-putting to have the car running worse after so much work.