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I have two questions here guys.

Are the Heater matrix Pipes the ones that come through the bulkhead and attach to the enging water hoses?

If they are, how much of a pain are they to replace? My pipes (that are coming through the bulkhead) are all corroded and when I change the water hoses, I am worried that they may break. Got a feeling that to change these pipes it would be a big job with the dash out.

http://www.rimmerbros.co.uk/Item--i-AAP273PIPES

The heater has to come out to replace those pipes so its not a quick job. There is a stainless steel replacement available now which will last forever but your problem then will probably be with the dreaded matrix seals where the pipes connect into the heater core. If you disturb those seals the chances are they will leak and they are no longer available. Folks have bodged them with all kinds of sealants but its never a good job.
You might want to replace the whole thing with one of the alternative types of matrix such as S&S sell which uses normal hose outlets.

standard heater set up looks like this


heater with an alternative matrix looks like this so you can add ordinary hoses or use pipes to the engine bay.


My car had leaky seals even with the stainless pipes so I cut down my stainless pipes and used them like this.


Have a look at my blog here which has a full blow-by-blow account of the job. ps (I also have a spare set of SS pipes)
viewtopic.php?f=16&t=21406&start=15

Hi Phil,

Your wedge has been fortunate if your still on the original mild steel heater pipes and rubber seals. The pipes on mine rusted where they slid inside the rubber seals eventually breaking the seal. It was a fiddly job taking out the dash, just as bad taking out the heater unit and an even worse one extracting the matrix out of the heater. Lots of rivets in a brittle plastic casing that have to be drilled out, oh and if you don't use an ultra sharp drill bit, the plastic can melt with the heat and then it can crack when riveting the case back together again.

But I managed it and it looks like I'll be doing it again in the next few months as my wedge has sprung a leak even with s/s pipes and replacement seals. At least in the DHC you can take the hood down to give some room. It must be worse in a FHC

Thanks for the replies guys. I do have the mild steel pipes and currently with no leaks. Not sure if they have been changed in the past though by previous owners. I am a bit frightened to change the water hoses though as itlooks like the steel pipes will not last too much longer.

I like the idea of cutting the stainless steel pipes and fixing rubber hoses with jubilee clips to make the seal needed. However, that would mean buying a new heater matrix which has the new pipes fitted to attach the rubber hoses too, which means more cost. It is a shame that we cannot get them in polly.

Has anyone added any after-market heater units to cut down on weight and space taken up by the older unit?

Phil,

There's a Jetta / Golf Mk1 heater matrix that others have used. It sells for around £20 - £30 on eBay in the U.K from several sources.

Regarding replacing the whole heater box, I've never seen a solution. Have you looked at the second half of this thread? viewtopic.php?f=2&t=23637


Adam

Phil,
Ditto Adam's comment re the other related post ..."what a great day for....".

I have the Golf/Jetta/Rabbit heater unit fitted, a small trim of the heater casing where the pipes pass through and drops in almost as if designed for the job. Check out the 'Bay, attractive price online from various suppliers, and shipping to Oz from UK was reasonable and quick.
The aforementioned post also includes a link to previous post on this forum that includes a step by step conversion with various photographs of required trim and installation of the VW unit. Good luck.
Rgds, DM

I fitted a Jetta matrix a couple of years back but haven't fitted the unit to my car yet as it's still a work in progress. I remember it was a really tight fit and I had difficulty fitting the two halves of the casing together but I did manage it. I would like to know which is the feed and return on the Jetta matrix, there was a diagram on here but the link is dead now. Also the OD of the inlet & outlet is aprox. 16mm, I think 13mm ID hoses should fit but I havent checked, just another headache while trying to work out the coolant flow from an electric water pump. I was thinking about doing away with the metal pipes and fitting flexible silicon hoses all the way from the matrix to the engine to reduce the number of joints. It'll probably need a guide bracket at the bulkhead but it should work

I don't think there is an IN or OUT as such so take you pick.

Thanks, I don't think it'll make much difference either way.

That is an impressive layout of heater parts

It took a while but I got there eventually, one day I hope I'll get to fit the thing.

Phil, the answer is, STAY IN OZ, where you can simply bypass the heater. This stops the hot water going into the cockpit keeping it cooler in summer, & improves the engine cooling at the same time, with the flow avoiding the heater matrix.

I bypassed mine about 14 years ago, & would you believe, it has given no trouble since.

Hasbeen

Lol I like your answer Has been. I had to read it twice before I got the message. I was even going to ask where you could buy 'Stat in Oz'

Tis the season for heater maintenance! I am rebuilding mine also and have a question regarding the Thermal Cutout used in conjunction with the resistor wire. The original OTTER on mine had broken and I have searched but been unable to buy the same replacement. (I know that Rimmers have them but I don't want to buy the whole wired assembly).
I have fitted a common type available but do not know what temperature the original will operate and open the circuit. I took a guess at 100 *c.

Does anyone know what the setting should be?