Heater Matrix Replacement - Any Tips?

[James_G]

Chaps

Following on from my recent thread where I determined my heater matrix was kaput, I am now setting about replacing it.

Work so far has progressed well and using the Clarks Garage guide, the dash has come out this morning. Nothing significant to report other than I had a bit of trouble with the A pillar trims. Seems they weren't removed when a new windscreen was fitted and so they were firmly stuck. Once freed though, the rest was relatively simple, and here's what it looks like now []:

Now that the dash is out of the way I need to get access to heater matrix itself. Has anybody done this bit and can advise? The matrix feels like it would slide out easily, but there's lots of pipework in the way. Is it easier to just remove the whole heater box?

Also, I obviously have to remove the water from the heater matrix, but do I have to drain the whole car of coolant. Assuming water will find it's own level, I suspect I do, unless there's a valve I can close off somewhere. Again any help or advice welcome.

Finally, some positive feedback on Porsch-Apart who I spoke to yesterday afternoon and got me a solid 2nd hand matrix by 10am this morning.

 

[James_G]

Right then, it's out. Here's some pictures of the remaining steps.

Firstly I had to drain the matrix, as after discussing with Porsch-Apart it turns out you don't need to drain the whole car. The pipework comes apart very easily and I just caught the coolant using a big saucepan:

As I predicted the matrix does just slide in, but the driver side footwell vent is in the way, and you can't access the screws to remove it with the heater box in situ. So the heater box has to move. Here's that vent blocking extraction:

I struggled at first with working out how to remove the heater box. There's two nuts inside the car just under the windscreen, shown here:

And I'd been advised to remove the six bolts holding the heater blower down, which is of course accessed from under the bonnet. This having been done it wasn't budging and so a big thanks to Jon Mitchell (Indie9xx on here I believe) for setting me straight, that being that you not only have to remove the bolts but you have to remove the whole heater blower assembly. This is shown below, note slight rust, more on that later.

This leaves you with a big hole, through which you can see the top of the heater box.

Now freed up, the heater box can move to the left enough to enable me to remove the ventwork that was in the way and slide the heater matrix out into the drivers footwell.

Close inspection of the heater matrix shows that it must have been weeping for some time, as there's lots of green copper corrosion. The foam surrounding it was soaking, and as you can see, it's not too pretty

Continuing my inspection I had a good look at the blower motor and when I turned it over I saw this to my horror[]

It still works, just, but I'll be replacing it. I have no doubt that this has been caused by the water leaking into the motor casing, because the big plastic panel protecting it was cracked. Having recently bought a new one, I would advise anybody with a cracked cover to replace theirs immediately so that they don't experience the same thing. They're £35 ish from an OPC and very simply to fit.


So that's it, the car is as far away from driveable as possible [] but I've blocked out all of tomorrow for re-assembly. As always feedback welcome, and if there's demand I can write this up as a FAQ as there are plenty more pictures. Having said that, I hope very few of you ever have to do this, it really does look very scary when it's all out!!!

 

[pauljmcnulty]

Blimey - brave man! []

If you're happy to keep photographing and documentiing this repair it's a no-brainer for the faqs area. As with any jobs people do on the cars, if you can supply pics and a decent write-up of the process it's going to help everyone.

Just out of interest. With the work involved what was the reason for going for a used part over a new one? I'd have thought that any price was worth it to forget about replacing something so labour-intensive for 20 years!

 

[James_G]

Paul

This thought did cross my mind, but my heater matrix is from a low mileage Jap import, and it does look very clean, so I figured that I would save the £200 odd quid extra for a new part. If it doesn't work, then I'll pull it apart and do it again, because currently my time is "free", but money is drying up.

Also I am finding it increasingly difficult to keep plowing money into a car which continues to lose value. We all preach here about buying on condition, and with all the recent new parts mines got to be getting on for one of the better ones, but all prospective purchasers* seem to see is the headline figure of 156k miles, and the fact that it doesn't have leather.

The proof is in the recent sale of a £2000 Turbo, which will no doubt need buckets of cash spent on it, whereas say a nice S2 that needs no work for £4000, is almost a pipe dream these days. Buyers don't think long term, they just see their initial purchase price, and think that's all there will be. Of course, we know they'll regret it - the fools!!!!!

Cheers

James


*Not that I am selling, you understand.

 

[pauljmcnulty]

Also I am finding it increasingly difficult to keep plowing money into a car which continues to lose value. We all preach here about buying on condition, and with all the recent new parts mines got to be getting on for one of the better ones, but all prospective purchasers* seem to see is the headline figure of 156k miles, and the fact that it doesn't have leather.

Understand totally how you feel. Hence me considering not ploughing any more money into my 944.

I look at the other way, including purchase price, depreciation, reliability, parts availability, driving experience in the real world of the cameara-city that is suburban London......[8|]

All things considered my next value-losing car will be? Watch this space. []

 

[James_G]

Right, all done and success! Just been for a test drive and no leaks. Here's the proof, taken just before 6pm this evening:

I reckon it's taken me 12-14 hours to do, although that has included hoovering up a bit, tidying some wiring under the dash (a legacy car phone install I suspect) and not rushing. Looking back I'm not sure quite how I did it, but then I guess I just get on with it, or the car rusts from the inside out.

So, FAQ coming up shortly, where I'll highlight some of the issues that I came across.

Meanwhile has anybody got a wet/dry vac they can lend me - my floor mats need a damn good clean to remove the coolant marks?

 

[sy247]

If you could provide as much information on this I would really appreciate it. I have got my mechanic doing the same job on my S2 in a week or two's time. He is a good mechanic but he hasn't worked on 944's before as far as I am aware so any tips would be well received.

I have had the car a year and replaced discs and pads all round, belts, rollers, water pump, some engine oil seals (that wasn't cheap), bit of spraying on the front spoiler, two new tyres, a couple of services at my local indie. It all adds up, but I love the way the car handles and its character when belting down a nice B road or a sweeping A road. People are also often quite interested in the car and I have not had any negative comments about it at all.

But I still fancy a 911 (as well)!

 

[Indi9xx]

Glad I was able to help!

As I said on the phone, your a brave man to do this job and it looks like you did a good job of getting everything back in there!

I have always loved the grey logo interior!

 

[zcacogp]

James,

Sorry - I'm picking up on this thread a little late, but that looks like a very brave exploit. Well done - for realising the problem and having the balls to get stuck in. But then I have also been in the situation where what looks like a 'small' job gets bigger and bigger by the minute when you are in the thick of it ...

I sympathise with the comments about the cost to run these things, and the fact that you almost certainly won't get it back when you sell. And also about the stupidity of buyers seeing the high milage and walking off. I guess the only way to rationalise it is to look at the depreciation anything remotely modern would suffer and realise that, for the purchase price, a good 944 delivers a lot.

I guess what I am saying is that we are running cars that would have cost over £40k 18 years ago, and we should expect bills commensurate with that. However this is not much comfort when you are out of contract (as I suspect you are still), hence no money coming in, and looking at having to spend another three figures on the car.


Oli.

 

[James_G]

Simon

I should be finishing the FAQ within a day or so, meaning it should be with you before your car goes in. Out of interest, how many hours has your mechanic allowed for the job? I am just curious to know how much money I have saved myself if I am honest! And to see if I was working slowly or not when doing mine.

It's just a suggestion, but have you thought about doing it yourself? I know it looks a nightmare but if you are methodical it isn't difficult and other than needing a 24mm socket for the steering wheel you only need the very basics tool wise, such as you'd find in a simply car mechanics tool kit. I suppose it could be time/space issue however.

Meanwhile, did you ever get round to converting your S2 for track use - I know you posted about it previously? Or have you decided to keep it standard? I ask because I've been doing them in mine and they really come into their own as cars on the track. No point keeping it as a garage queen I say.

Cheers

James

 

[sy247]

Hi James,

I took it to my local indie who didn't even really want to diagnose to fault (becuase the dash would have to come out) but said because coolant was leaking from under the dash it was likely to be a heater matrix. He quoted 'not much change from £1000' which of late seems to be a recurring pattern. He advised I sell car which I wasn't terribly impressed with given the amount of money I have spent with him over the last year and that the car should be getting to a point where there isn't much else that could go wrong that hasn't been changed! My indie charges £50p/h and the part from Porsche was £270 so by my calculations he allowed himself 14 hours which I thought was somewhat excessive for a specialist. In reality I don't think he could be bothered.

My non specialist (but still excellent) mechanic is allowing one day. He is working on less than half the labor rate of the indie. I do not really fancy trying it myself becuase I struggle with even putting up a shelf in the house so a 944 dash might be a bit too much for me to manage...

On the subject of stripping the car out I still really don't know what to do. I work in IT on a contract basis and the market is pretty dire out there, so at some point in the not too distant future I might be on the bench for longer than usual. So at the moment I am not spending unless it is really necessary. I am going to get the car back on the road and do a few track days this summer in standard trim and see how I get on. If I am going to keep it standard it really needs a few areas of surface rust attending to and a respray and some work done to bring the interior up to standard so either way it is not going to be a cheap exercise!

 

[James_G]

Oli, yes, out of contract but ironically I am being more productive than ever, but I think that's more a negative reflection on the modern service industry than anything!

In the end to the total cost has been £62 for the 2nd hand part delivered and a few screws for the blower cover that snapped off when I disassembled. I thought I was going to need a new blower motor but fair play to Denson/Nippon industries, even with all that rust it works fine. Can't be long for this world though so I'll pick up a smarter 2nd hand one soon.

Simon, good luck with your mechanic but it's a shame your local specialist didn't want to touch it. Given you and I have had this problem within the last few days, I can't see it not cropping up again for others on here. Trouble is pick the wrong car at the wrong specialist with the wrong owner and it'll end up getting scrapped, even though it doesn't need to be a deal breaker.

As for track days, I use mine in totally standard trim, albeit with brand new OEM spec Porsche springs, dampers, discs and pads (the originality police will be pleased[]), and it's brilliant. I suspect there would be great benefits to come from stripping it out, but as has been discussed here before there's a massive difference come resale time between a semi track car done at home and the real deal done by the likes of EMC. For that reason, I'm keeping my rear seats in place and leaving it all as standard, save for the steering wheel. Plus, being non leather I doubt my interior is worth much, and like Jon above, I really like it.

 

[TTM]

James, I admire how got through all this.

I had the same issue a couple of years ago but as soon as I saw the mess once I had taken the dashboard off I put it back on and brought the car to a shop [>:]

 

[James_G]

As promised I've now written up an FAQ on replacing the heater matrix, which can be found here:

http://www.porscheclubgbforum.com/tm.asp?m=455851

Cheers

James

 

[vitesse]

James ,
Great write up-but all the more reason to run a 924S rather than a 944.I replaced the heater matrix on our 924s some years ago -I didn't need to remove the dash,steering wheel or anything much other than to make space for the matrix to slide out into the driver's footwell-if I remember,the hardest part was releasing the rubber hoses at the bulkhead & getting them back on again with one's head & shoulders under the steering wheel.So the heaters must be totally different & if I wasn't lazy I suppose PET would point that out.

Colin.