GUII heater core replacement

[jff45]

I’m looking at starting on this in the next couple of weeks. It’s been bypassed for the last 2 years but we plan on taking the caravan south into cooler weather in August so will probably need it.
I’m aware it’s the whole dash out which doesn’t bother me. I also know there’ll be lots of wiring to tidy up after all the stuff I’ve added over the last 14 years.

I’ve been trying to get some info on
which GUs have the heater core with the tap in the plastic pipe. I think mine might be like that judging by info on Patrolapart.
Have also read that the thicker later model will fit with some slight modification to the heater box.

Has anyone replaced the model with tap and fitted the normal pipes? Problem will probably be finding the pipes without paying drug money for whole genuine core.

[mudski]

I did my GUII a while back. A bitch of a job to do. Wasn't hard just a lot to remove and refit. My GU is a 8/2001 and is uses the cheaper unit that PaP sell. Put your VIN into here : https://partsouq.com/ and this will tell you what core you have.

[jff45]

I did my GUII a while back. A bitch of a job to do. Wasn't hard just a lot to remove and refit. My GU is a 8/2001 and is uses the cheaper unit that PaP sell. Put your VIN into here : https://partsouq.com/ and this will tell you what core you have.

Cheers Mark, I did the Partsouq search last night to confirm it's the heater core with the tap. I'll wait till I have it out to see where it's leaking before I decide what to do.

[mudski]

Cheers Mark, I did the Partsouq search last night to confirm it's the heater core with the tap. I'll wait till I have it out to see where it's leaking before I decide what to do.

Is it leaking in the cab? Is yours a Ti? I’m trying to think why the cores would actually be different. Plus I honestly thought all GU Patrol ran heater cores without a tap. Having a tap would be great for summer as mine, even with all new foam sealy bits on all the diversion flaps, I get hot air coming out of the vents when it’s set to cold and the fan/ AC off. I wonder if shutting the hot water flow off to the heater core would help.
I actually thought of installing a VT Commodore heater tap in mine and some how using a servo motor to shut the water off. The VT taps don’t just shut the water off but divert the water back into the cooling system so there is no dead flow I. The cooling system.


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[Hodge]

Hairy job it is. Hope I never have to trek that trail my self. [emoji1696][emoji1696][emoji1696].
Have heard of mechanics refusing the job. That's saying something.

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[jff45]

Is it leaking in the cab? Is yours a Ti? I’m trying to think why the cores would actually be different. Plus I honestly thought all GU Patrol ran heater cores without a tap. Having a tap would be great for summer as mine, even with all new foam sealy bits on all the diversion flaps, I get hot air coming out of the vents when it’s set to cold and the fan/ AC off. I wonder if shutting the hot water flow off to the heater core would help.
I actually thought of installing a VT Commodore heater tap in mine and some how using a servo motor to shut the water off. The VT taps don’t just shut the water off but divert the water back into the cooling system so there is no dead flow I. The cooling system.


Sorry for the belated response, I was taken out of action for a week.

Mine started leaking into the cabin during our return from Lorella Springs in 2019. I just pulled over and did a bypass at the thermostat housing that's still there today.
Yes, mines the Ti and, until I started to look at fixing it, I also believed GUs had no tap. It appears to be the early GUs and I'll try to research if the tap is the only difference and if it can be removed because I plan to replace it with the later model pipe if possible. I don't like the idea of putting the 20 year old tap back in and the new cores with tap (at $800) can't possibly be recent manufacture so still risky in my view.

Where do they typically leak from?

[jff45]

Hairy job it is. Hope I never have to trek that trail my self. [emoji1696][emoji1696][emoji1696].
Have heard of mechanics refusing the job. That's saying something.


They probably want to avoid the inevitable DIY wiring nightmares that lie peacefully in their tangled mess just out of sight.. :)

[Hodge]

They probably want to avoid the inevitable DIY wiring nightmares that lie peacefully in their tangled mess just out of sight.. :)[emoji1787]
So true. Mechanic's worst nightmare.
Opening a owner-wired coloured spaghetti home ellecky can of worms job ! [emoji106][emoji106]

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[jff45]

On top of that, everything that goes wrong with the car afterwards will be because the mechanic took the dash out..

[jff45]

There’s a guy selling a heater unit not far from me that has the tap version core. I’ve offered him $50 so I can have something to study beforehand. Should hopefully be able to see if the tap can be removed and have it functioning like the later models.


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[mudski]

I'd actually prefer having a tap. Atleast there will be no hot air leakage when its on cold like mine does. Even with all near seals on every diversion flap in the heater box.

[jff45]

I'd actually prefer having a tap. Atleast there will be no hot air leakage when its on cold like mine does. Even with all near seals on every diversion flap in the heater box.

In theory so do I but I just don’t like the idea of putting the 20 year old tap back in with the amount of work involved. Nissan didn’t keep the tap version for long and I haven’t read a lot of complaints about hot air entry in general.
I’m trying to determine if any other mods were done to the heater box when the tap model was abandoned. If it’s all still the same then I prefer no tap.

I’m guessing that any new heater core with tap like Patrolapart sell would have been manufactured a long time ago anyway and I’m not willing to spend $800 with that kind of risk.

[mudski]

If I could somehow use a VT/VY Commy heater tap which recirculates the water at the tap rather than just blocking it, I reckon thats the go.

[jff45]

I spent $50 today on a complete heater block unit with AC evap and blower, etc and I’m surprised to find the tap is really well made. This heater core wasn’t leaking but I suspect they get damaged because the foam that fits them snuggly in the box just completely disintegrates over time and the core can shake about over bumps.
Anyway, I thought it was worth the small expense to get a preview of what needs doing to take it apart.

Hope I can make a start on it in a week or so..

[jff45]

I took this spare heater box apart and thought some GU owners might find this interesting.
This is how blocked up the AC evaporator can get if you don’t do the cabin filter mod..

83759

[jff45]

This is how I plan to get rid of the tap. The right side tube is almost the same angle as the tap so I cut off the flange on the left leg where the tap was attached and cut the leg off the right side tube and this should allow me to make a replacement part.

The pics show where I’m at with it. The tube is 1.6mm ally so I can TIG that no problem.
I just need to make up a jig so I make it exactly the same as the tap elbow.
If I bugger it up I’ll just reuse the original tap..

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[MB]

There is no end to your Fabrication/Upgrade Legendary Skills John Mate [emoji106][emoji106]

Thanks for sharing as Always [emoji736][emoji736]

FWIW: Once cleaned the horrifically blocked (looked like solid mud, only indoors dust & moisture) heater core out on our old Family 2001 GU insitu without removing the entire dash as was dreading it and thought I knew better….can do attitude [emoji23]
My neck is still sore, fingers are still scarred and elongated and the plastic surrounds up under its dash are still speed taped back together due to aggressive/frustrated removal and re-installation [emoji2959]
IT can be done though……NOT recommended [emoji107][emoji107][emoji23]


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[jff45]

The heater core i have here is still like new. The AC evap acted like a filter because all the air goes through it first.
Here’s the core showing how the foam has disintegrated with age.

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[jff45]

Sitting down at my welding table playing with this heater tap mod and happened to look up to find this guy taking a nap here. Maybe digesting the neighbour’s cat..
He’ll probably hang around for a few days.


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[jff45]

I did my GUII a while back. A bitch of a job to do. Wasn't hard just a lot to remove and refit. My GU is a 8/2001 and is uses the cheaper unit that PaP sell. Put your VIN into here : https://partsouq.com/ and this will tell you what core you have.

Mark, just to clarify, yours is 8/2001 and it already had the heater core with no tap?

[jff45]

Well here’s an interesting twist. I’ve just looked up under my dash with a mirror and lo and behold i have no tap on my heater core. The 2 ally pipes are clearly visible.
The Partsouq catalogue is wrong for my VIN.

[mudski]

Mark, just to clarify, yours is 8/2001 and it already had the heater core with no tap?

Correct...

[mudski]

Well here’s an interesting twist. I’ve just looked up under my dash with a mirror and lo and behold i have no tap on my heater core. The 2 ally pipes are clearly visible.
The Partsouq catalogue is wrong for my VIN.

I have the Nissanfast Program on my laptop at home. I could check that for you if you like.

[jff45]

I have the Nissanfast Program on my laptop at home. I could check that for you if you like.

Thanks but no need mate, I can easily see up under the dash that there’s no tap. Don’t know why I didn’t think to look before then it occurred to me the other day that I have a little BT borescope that might show something but tried first with a mirror and torch and surprised to see it no problem.

I’ve decided to start taking it all apart tomorrow morning..

[Hodge]

John. Could you lay out out in laymans terms to the nuffy rest of us what this tap is all about?
As mentioned earlier, I hope i do not ever need to endeavour this task. But would like to arm my self with facts if need arises.

Also...
I LOVE you how casually state that theres a chunky full bellied carpet snoring above your work area and go about your business lol. Most inhumans around here would run to the next suburb or grab the first sharpest objects they'd get their hands on.

[Brissieboy]

Also...
I LOVE you how casually state that theres a chunky full bellied carpet snoring above your work area and go about your business lol. Most inhumans around here would run to the next suburb or grab the first sharpest objects they'd get their hands on.

Carpet snakes/pythons are a farmers best friends. I lived on a farm for more than half of my life. When we found a carpet, we put them in the hay shed - great for keeping rats and mice under control (as long as there wasn't a plague of the pesky little rodents). Often found skins as we used up the bails of hay but didn't see the snakes too often.

[jff45]

John. Could you lay out out in laymans terms to the nuffy rest of us what this tap is all about?
As mentioned earlier, I hope i do not ever need to endeavour this task. But would like to arm my self with facts if need arises.

Also...
I LOVE you how casually state that theres a chunky full bellied carpet snoring above your work area and go about your business lol. Most inhumans around here would run to the next suburb or grab the first sharpest objects they'd get their hands on.

I doubt your later model would have the tap. It appears to be something Nissan added to the early GUs and was actioned by the mixer flap - the flap that controls how much air goes through the heater core.
Most info I’ve read isn’t very accurate about when the tap was discontinued.
If you get a mirror and torch you can easily see what you have.

Couple of not very good pics here to show the heater box with and without the tap. In the pic with the tap you can see the rod that connects to the pivot of the mixer flap and you can see the mixer flap slightly open

8378783788

[jff45]

He decided to move this morning..

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=83789&stc=1

[Hodge]

He decided to move this morning..

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=83789&stc=1I love em.
Helped a snake catcher mate out for a while , but never had a chance to meet a python in the wild being in Vic.

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[Hodge]

I doubt your later model would have the tap. It appears to be something Nissan added to the early GUs and was actioned by the mixer flap - the flap that controls how much air goes through the heater core.
Most info I’ve read isn’t very accurate about when the tap was discontinued.
If you get a mirror and torch you can easily see what you have.

Couple of not very good pics here to show the heater box with and without the tap. In the pic with the tap you can see the rod that connects to the pivot of the mixer flap and you can see the mixer flap slightly open

8378783788So this tap shuts off flow of coolant through the heater core entirely? Instead of letting it flow through, and just rely on the selection flap to keep heat of vents ?

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[jff45]

I didn’t study it too closely but I assume it shuts off progressively depending on the flap position. It would logically be fully closed when the flap is closed such that no air passes through the heater core. Halfway flap would probably be half flow hot coolant.

I’m happy I don’t have the tap so I don’t need to worry about reusing an old unit.

[jff45]

Made a start on it this afternoon. Nothing difficult up to this point.
I’m surprised I had a hollow TX50 spanner to get the airbag bolts out..

83791

[mudski]

Have fun mate. When I did mine I made entire new, "aftermarket" wiring looms for all the "bolt on " accessories.

[jff45]

Yes, I need to do some serious tidying up in the wiring. The hardest part will be tracing what some of it does but that’s ok, I’m in no hurry.
I find this kind of thing is a pretty satisfying way to stay active during retirement :)

[jff45]

The centre radio surround in 'faux bois' has cracked in several places so I'm thinking of 'reconstructing' it with superglue/baking soda and vinyl wrapping it in 3M carbon fibre. This means I'll have to do the shifter surround as well so it doesn't look too silly. Probably won't bother with the door trim 'faux bois' bits.

Anyone done this already? I've been watching a few YT vids and it looks like a patient DIYer could handle it.

[0-TJ-0]

The centre radio surround in 'faux bois' has cracked in several places so I'm thinking of 'reconstructing' it with superglue/baking soda and vinyl wrapping it in 3M carbon fibre. This means I'll have to do the shifter surround as well so it doesn't look too silly. Probably won't bother with the door trim 'faux bois' bits.

Anyone done this already? I've been watching a few YT vids and it looks like a patient DIYer could handle it.

I just picked up some from the post office(eBay) yesterday to have a go at doing my bonnet scoop. All the clear coat came off it. Thought it seemed like an easy part to have a go at wrapping (except I don't know how I'm going to do the inlet hole). I don't really want the scoop to be carbon fibre but I thought it might look less sh.t than faded paint.

I think it only cost $20 for a reasonable sized piece. Haven't pulled it out of the envelope yet.

[jff45]

I've ordered 3M brand stuff and the 1524mm x 500mm sheet is around $60. Also ordered a kit with the squeegee, etc.
Carbon fibre was just the lesser of all evils because I don't want coloured stuff nor matt black or brushed silver, etc.

Throw up some pics when you get into it..

[jff45]

Bit more progress


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83805

[Rossco]

Yeah wow big job, good luck[emoji106]

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[0-TJ-0]

I've ordered 3M brand stuff and the 1524mm x 500mm sheet is around $60. Also ordered a kit with the squeegee, etc.
Carbon fibre was just the lesser of all evils because I don't want coloured stuff nor matt black or brushed silver, etc.

Throw up some pics when you get into it..

After reading your reply this morning I thought I might be better off ordering some 3m stuff too. Turns out the sheet I ordered was only $13.. thought it might be good to have a practice sheet anyway.

Bit of a learning curve trying to get it to go around corners.. took me the better part of an hour to get this far on an old toolbox lid.

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[jff45]

I think the carbon fibre design like that will look ok on the radio & shifter surrounds. Probably better than the 20 year old plastic wood

[jff45]

Heater box is finally out. Takes a bit of pushing and shoving but not too hard.

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Leaky heater core..

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Looks a mess..:)

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[mudski]

Bit more progress


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83805

All that just for a bloody heater core hey…


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[jff45]

All that just for a bloody heater core hey…


Yes, but a lot of satisfaction when you can do it yourself.
I sent the pics to my grand kids in the US and said "look what Grandpa is doing at 76" :)

[Hodge]

Heater box is finally out. Takes a bit of pushing and shoving but not too hard.

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=83807&stc=1

Leaky heater core..

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=83808&stc=1


Looks a mess..:)

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=83809&stc=1

Have mercy...
My PC froze up when I scrolled to that last photo... Computer says NO!
If mine ever leaks, there will be very cold winters I tell ya... By-pass/plug it up in the engine bay, and rug up ! lol

[jff45]

Went and saw Mat (nissannewby) this afternoon to pick up the new aftermarket heater core. Saved me paying the drug money that some are asking.
Reused the old orings with some copper RTV and now have it fitted snugly back in the heater box. Bunnings tomorrow to get some sealing foam for the top of the heater box where the old stuff had disintegrated.

Also started getting the surface rust off the metal parts so I can give them a quick coat of epoxy enamel. I know I’ll never see them again but I just can’t put them back rusted like that :)

[mudski]

Went and saw Mat (nissannewby) this afternoon to pick up the new aftermarket heater core. Saved me paying the drug money that some are asking.
Reused the old orings with some copper RTV and now have it fitted snugly back in the heater box. Bunnings tomorrow to get some sealing foam for the top of the heater box where the old stuff had disintegrated.

Also started getting the surface rust off the metal parts so I can give them a quick coat of epoxy enamel. I know I’ll never see them again but I just can’t put them back rusted like that :)

Yeah I did the same, replaced all the foam bits in the heater box and painted the large steel cross bar thingo'. If you haven't already hose out the heater box and wash it. I got rid of a lot of dust that I didn't know was there doing this.

[PeeBee]

That is just inspiring. I hope I never have to get that far into my dash area.

[jff45]

Yeah I did the same, replaced all the foam bits in the heater box and painted the large steel cross bar thingo'. If you haven't already hose out the heater box and wash it. I got rid of a lot of dust that I didn't know was there doing this.

Mine wasn’t very dusty. I was able to wipe it clean inside. I didn’t want to wash it because the Ti has the electric actuators connected to it.
I’ve had the cabin filter in for a while now and I’m sure it makes a difference.

[jff45]

This is the section that the glovebox screws onto. I brushed with undiluted CLR and then used a pot scourer, one of those green plastic hobbies, to get the rust off.
I’ve since sprayed it with aluminium tone epoxy enamel and it comes up like new.

The 2nd pic is just the rust off not yet painted


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[jff45]

This is the main bar that most of the stuff bolts to. Lots of rust n the section under the cluster.

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Did the CLR + scourer treatment on it and it cleaned up pretty well.

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Gave it a good coat of epoxy enamel. These Hills Hoists are an absolute must have when you need to paint something and leave it to dry. I’ve sprayed hundreds of bits and pieces on this hoist..

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I got some good sealing foam from Bunnings this morning and now have the heater box ready to go back in.

When I took the heater box out, I found the top mounting hole was a bit of nuisance to get out because you have to really pull too much on the box to get it to clear the stud. I even whacked the bracket back a bit to try to make it easier.
I decided to cut the stud off with the Dremel and I’ve replaced it with a 6mm stainless rivnut. This should make it much easier to get the box back in without forcing too much.

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[jff45]

I put the heater box back in this morning. Took me less than 2 minutes thanks to the mod I did cutting off the stud.
I’ve highlighted the corner of the heater box that has to pass behind the AC unit. With the stud no longer there I was able to simply slide the box to the left to mate up with the AC and the 2 pipes slide easily through the opening in the firewall.

I’ve connected the heater hoses back in the engine bay and have the IC, etc all back in place so nothing more to do there.

83848

[jff45]

This is where I stopped early this afternoon. The bar is back in and everything that bolts to it, except the passenger airbag which is in the dash itself, is done. Steering column bolted back up, fuse block reconnected and screwed back in place.
Tomorrow will be dedicated to sorting out the extra wiring that I’ve added over the years. Might even get the Dymo out and label some of it :)


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[jff45]

Yes, he’s still there..

83943

[jff45]

Stopped for lunch yesterday and when I got back to the shed the snake was gone.

Made some good progress after losing a fair bit of time redoing shoddy wiring. Should be running before the weekend if I can spend enough time on it.

83977

[Hodge]

Stopped for lunch yesterday and when I got back to the shed the snake was gone.

Made some good progress after losing a fair bit of time redoing shoddy wiring. Should be running before the weekend if I can spend enough time on it.

http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=83977&stc=1

Hopefully hes not under your dash

[jff45]

You might laugh but each afternoon when I’d finished for the day I made sure all the doors were closed just in case he thought the interior might be more comfortable :) I assumed he’d get a bit upset if I had to drag him out by the tail..

[rusty_nail]

Diamond pythons are just the coolest though. Not sure if you've ever handled one before, but of the if it ever presents itself, put some weight behind the head to pin it, then grab it with one hand also just behind the head, the other hand can do what ever. That are a fairly placid creature and are great for cleaning up rodents around your place, unfortunately that like chooks too if that's your thing. Absolutely magnificent creatures

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[rusty_nail]

Just like this fyi http://www.nissanpatrol.com.au/forums/images/imported/2021/06/149.jpghttp://www.nissanpatrol.com.au/forums/images/imported/2021/06/150.jpghttp://www.nissanpatrol.com.au/forums/images/imported/2021/06/151.jpg

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[Hodge]

Diamond pythons are just the coolest though. Not sure if you've ever handled one before, but of the if it ever presents itself, put some weight behind the head to pin it, then grab it with one hand also just behind the head, the other hand can do what ever. That are a fairly placid creature and are great for cleaning up rodents around your place, unfortunately that like chooks too if that's your thing. Absolutely magnificent creatures

Sent from my SM-G965F using TapatalkAgree mate . They are majestic.
If I lived in QLD I'd make sure there was one around for sure.
Id be cautious in getting friendly with one however if inexperienced. Despite being so large and having a lazy appearance, their strike is no slower than their smaller lethal cousins... And they latch on good and proper as you can imagine.

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[rusty_nail]

Agree mate . They are majestic.
If I lived in QLD I'd make sure there was one around for sure.
Id be cautious in getting friendly with one however if inexperienced. Despite being so large and having a lazy appearance, their strike is no slower than their smaller lethal cousins... And they latch on good and proper as you can imagine.

Sent from my Pixel 3a XL using TapatalkSee above pics mate. definitely one of my favourite reptiles, up there with the thorny devil.

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[jff45]

Our younger son has had a diamond python in a glass terrarium in his apartment for years now (and wonders why he can't keep a girlfriend). He got it very small but it's about 1.5m now. I believe he had to get a permit for it.
He often takes it out for some "bonding" and occasionally it latches onto his arm with its mouth so he keeps a spray bottle full of water handy and sprays its face so it lets go.
He buys packets of frozen rats from the pet store and thaws them out to feed it.

I'm personally not a fan of caged animals but it's now too late to let it go..

[jff45]

I started on the carbon fibre vinyl wrapping tonight. This is 3M 2080 black carbon fibre bought on eBay.
No need for a heat gun, the wife’s hair dryer was more than hot enough.


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84000

[Hodge]

That looks very very neat John. Are you covering just the woodgrain bits or doing more of the dash frontage ??


The Y62 V8 shopping trolleys have that awful woodgrain across the interior. Suits the Westfield car parks I suppose ...

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[jff45]

The main piece I wanted to do is the centre around the radio that has become so brittle over 20 years that it cracks if you look sideways at it. I had to do this console piece as well otherwise it would look silly.
I need to reinforce behind the radio surround with ally filler rod and super glue/baking soda otherwise it will just crack somewhere while I'm wrapping it.
I did this console first so I can put it back in the car but the radio bit can be done even after the car is running again.
I might do the ashtray lid to see what it looks like. It's easy to take off if it looks too much.

If I really have nothing else to do, I'll cover the wood grain on the doors as well. They're easy to take off and not a complicated form to wrap.

[jff45]

Got the centre piece done tonight. A couple of small blemishes but nothing I can’t live with seeing as I've had it badly cracked for the last couple of years..


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[jff45]

It’s finally all back together and running. Everything appears to be working correctly. I’ve run it up to temp to get the heater working and it all seems ok.

I like the carbon fibre look now that it’s all in place. Means I’ll have to do the door trims now..

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[jff45]

The door trims are much easier to do. Driver’s side a little more work than the others that only have one button.


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[jff45]

He’s back..


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