Heater Matrix replacement/re-core

[Woody928]

Hi all,

It's become abundantly apparent recently that the heater on mine and my dad's 240z is dead, with the weather being what it is from a screen clearing and comfort perspective we've been looking at resolving this asap to continue with winter use.

Having investigated further last weekend there's hot water going through the bulkhead to the matrix however the return pipe is cold. Having clamped the pipes we found the control valve was working fine and having tried to flush the matrix to clear a suspected blockage however there was almost no flow. I'm quite satisfied that it is an aged and blocked heater matrix and looking at options as to how to proceed.

We're planning on stripping out the matrix, however I wanted to know what the general opinion was for these, just take it to a local company to be re-cored? or purchase one for the states?

Also any tips for removal would also be appreciated, I'm assuming with the passenger fan and pipework removed it can come out through there?

Cheers, Mark

 

[Rob Gaskin]

The matrix on my current 240Z was leaking when I got it. The heater was bypassed in the engine bay and luckily no water had damaged the carpet/floor. I was given a spare matrix with the car and fitted it.

I removed the heater-control panel, motor and ducting however when I came to remove the matrix I discovered that the matrix could have been slid out from the side of the heater box!

Anyway the next problem was that the replacement matrix was very slightly larger than the original. I managed to fit it in but it was really tight.

So try to remove it without dismantling half the dashboard/console. Be aware that there are differences in size so perhaps have your's re-cored, I'd be interested to know if this is poss. because I may have my original one done.

 

[Fairlineguy]

Had the matrix on my last car re-cored cost £90
I have spare matrix that I took out of my current car spare as I am fitting a/c

 

[Farmer42]

Before removing the matrix, check that the right-angled outlet pipe under the dashboard has not kinked or collapsed. If it is old, it is prone to doing this.

I had a similar issue earlier on in the year and instantly thought it was a blocked matrix. I went through the hassle of removing it, flushing it only to find that the outlet pipe had collapsed stopping the water flow. Replaced it and now have a lovely hot heater without the cost and need to replace the heater core.

You can get a replacement right angled hose from car builder solutions for a couple of quid. If that doesnt work then you can, as Rob said remove the core from the side of the heater box without removing the fan. You need to remove the control valve, disconnect the hoses and unscrew a plastic panel from the side of the heater box. It should then slide out.

 

[Woody928]

Thank you all for your responses, all very useful information as always!

Unfortunately It wasn't the pipework Farmer so I had to tackle the whole unit instead. Thanks for the warning regardless.

I tackled this job with my dad this afternoon and in the end have had to remove the whole heater box as we couldn't get the access we needed. It was a complete faff with the confined space as I am sure you all know too well, however eventually it slid out through the passenger footwell. I think the whole unit needs a complete strip down and refurb having probably never been removed from the factory. There's lots of corrosion and gunk visible through the bottom air ducts and ****/debris sitting on top of the core. Strangely the two screws which hold heater control switch arm on are almost welded on having come off fine last weekend. The amount of dust, dirt and grime under there is quite scary tbh so the hoover will be going in while the access is there.

I need to look at the unit properly when I'm not tired however my intention is to take the lot so someone in the know and get them to refub the whole unit. That way I shouldn't have any problems with a need core fitting in or anything. I'll get some photos up in due course and will let you know how my enquiries get on with a few local companies.

One things for sure I'm really not looking forward to trying to squeeze it all back together!

 

[MaximG]

Woody,

If your inclined to do the work I would take the dash out. Give the whole thing a good clean and will make putting the heater box back in far easier. It really isn't that difficult, I managed to do it on my own the first time I took it out. To be honest I'm impressed you managed to take it out without removing the dash.

Regards,

Mike

 

[Paul Henley]

Hi Woody, I overhauled mine with the dash out, made access a doddle. A few pics on here, not sure if they'll help. As far as I could tell the matrix was ok, but will find out when I eventually get water through it.
Paul

http://zclub.net/forum/showthread.php?t=23624&page=3

 

[Woody928]

Woody,

If your inclined to do the work I would take the dash out. Give the whole thing a good clean and will make putting the heater box back in far easier. It really isn't that difficult, I managed to do it on my own the first time I took it out. To be honest I'm impressed you managed to take it out without removing the dash.

Regards,

Mike

Hi Mike, how much work is it to remove the dash then? I must admit there certainly looks to be 46 years worth of dirt and grime in behind there, its quite disgusting how much dust and dirt there really is however I don't think under the dash was touched at all as part of the restoration so no surprise! lol it did take some persuasion tbh, however once I worked out all of the bolt locations it was fine. I'm just far more concerned with reassembling it all having never had the pleasure of doing so before. Depending on your thoughts/comments on stripping the dash then at the very least the hoover will be put through there!

Hi Woody, I overhauled mine with the dash out, made access a doddle. A few pics on here, not sure if they'll help. As far as I could tell the matrix was ok, but will find out when I eventually get water through it.
Paul

http://zclub.net/forum/showthread.php?t=23624&page=3

Thanks for the comments Paul, I've got slightly caught up in the attention to detail in your whole restoration! Looks like an amazing job Really interesting to have seen the heater shot blasted and resprayed as that will be just what mine needs and I think I've found the place. You've got me tempted to look at doing my fan as well now though Oh its never finished.

I'm hoping to get down to a local place called Guildford Radiators who came by recommendation by Russ on here so hopefully there will at least be more news to follow with the restoration element

Cheers, Mark

 

[Jimbo]

one thing you can try once you have the matrix out is to fill it with cokacola and leave it for a few days.
the coke will eat and descale and you would not believe the crud that came out.
its a cheap option before before you bin it at least

 

[Woody928]

one thing you can try once you have the matrix out is to fill it with cokacola and leave it for a few days.
the coke will eat and descale and you would not believe the crud that came out.
its a cheap option before before you bin it at least

Thanks for the suggestion Jimbo, I've heard a few people same the same about using washing machine tablets.

It's now been dropped off at Guildford radiators anyway now for them to have a look in the new year. The whole unit is in need of a refurb so I'll have more peace of mind just dropping a new core in there, get the whole unit shot blasted, repainted and re-cored.

On a separate note I'm planning on doing a coolant system flush once the matrix has been reinstalled given I have no idea how old it is. Any ideas what coolant I should be using? all I know is that it is green.... (really helpful I know).

 

[toopy]

On a separate note I'm planning on doing a coolant system flush once the matrix has been reinstalled given I have no idea how old it is. Any ideas what coolant I should be using? all I know is that it is green.... (really helpful I know).

Any standard Glycol type antifreeze, nothing fancy required, chances are it will be blue not green tho.

Remove the thermostat and rad bottom hose and flush with a hose in the thermostat housing, block the out flowing water from the bottom hose with your hand and allow the water to back up and then release, keep doing this until all the water is nice and clear.

I would do the engine/rad flush before plumbing in the heater core, disconnect the two hoses at the bulk head and prop them up vertically to allow the block to fill fully.

 

[toopy]

In addition, if you have the pipework still connected that runs from the thermostat housing through the inlet manifold and then round the back of the block,
I would remove and check/flush the bits of hose seperately and especially the metal piece that runs round the back of the block, as these are notorious for getting choked with crud.
Ensure the pipe that runs through the manifold is clear as well.

Or do what i have and remove/disconnect it all completely, it's not really needed in the UK climate anyway, it never gets that cold here!

 

[SeanDezart]

Just for info, I have a vgc OEM 240Z unit now for sale, came out of mine and was new in 2006 - never a problem with it, no leaks, works perfectly....I merely had an opportunity to acquire a new, after-market version.
Good luck with the refurb.

 

[Woody928]

For those interested, the job is now complete. I've just added a write up on my project thread linked below with pics as well. Thanks for all of your input

http://zclub.net/forum/showthread.php?t=27161&page=8

 

[Woody928]

Any standard Glycol type antifreeze, nothing fancy required, chances are it will be blue not green tho.

Remove the thermostat and rad bottom hose and flush with a hose in the thermostat housing, block the out flowing water from the bottom hose with your hand and allow the water to back up and then release, keep doing this until all the water is nice and clear.

I would do the engine/rad flush before plumbing in the heater core, disconnect the two hoses at the bulk head and prop them up vertically to allow the block to fill fully.

In addition, if you have the pipework still connected that runs from the thermostat housing through the inlet manifold and then round the back of the block,
I would remove and check/flush the bits of hose seperately and especially the metal piece that runs round the back of the block, as these are notorious for getting choked with crud.
Ensure the pipe that runs through the manifold is clear as well.

Or do what i have and remove/disconnect it all completely, it's not really needed in the UK climate anyway, it never gets that cold here!

Sorry guys I thought I had previously replied to these. Thanks for the info, a full flush of the system is on the cards so this will be particularly helpful! Will also source some Glycol type antifreeze.

At -5 Celsius watching my breath in front of me it became quite essential on my priority list as well as for screen demisting purposes. I do use my car all year round though which I know some don't...

Just for info, I have a vgc OEM 240Z unit now for sale, came out of mine and was new in 2006 - never a problem with it, no leaks, works perfectly....I merely had an opportunity to acquire a new, after-market version.
Good luck with the refurb.

Thanks for the offer dude, seemed to make sense to go for a spanking new item though as I really didn't fancy doing to job again any time soon.