Seized heater controls

[Enright]

Somehow my heater and air distribution controls seem to have seized. The rod control for the air intake/blower assembly (that is hidden behind/underneath the fascia) is covered in rust and is solid, and the vacuum controls to change the air distribution aren't working either. If the internal flaps are mounted on metal spindles, perhaps they've gone rusty and seized too.

I don't quite know how, but on the car I've just bought it appears that water has been allowed to get into the air distribution system.
The blower works fine at all speeds, but you can hear water gurgling about inside, and see it escaping at certain joints behind the glove box.

At the moment I can see no alternative but to pull the entire fascia out in order to try to free up the controls and to trace whether it's due to rain water coming in, or coolant coming out.

I can't remember seeing this issue before, so has anyone else experienced this problem, and if so, what did you do to rectify it?

[epipete]

Never, when you pull the dash (which isn't hard but is time consuming) take some photos, I may have some parts of an old heater box in the garage in Chippenham (well I think that I have if they weren't dumped before I moved) which would be going begging - though possibly not before Christmas, I can ask my son go check!

When you get it apart Daves old friend Phosphoric acid might help!

[Enright]

Thanks for the response Pete.
I've had a dash out once before, and it wasn't much fun (it's pretty messy back there from before the days of more modular construction), but at least I was able to clear it out a bit and tidy up some of the "modified" wiring.
I'm hoping that it'll come apart easily enough, and will be reasonably easy to fix and re-seal. If it isn't, then I'm more than happy to pay P&P and give you some beer tokens for your old spare one.

[Candles]

You can get to quite a lot with the glove box and fascia thingy out - leaving the whole dash in place. As that work has to be done anyway, I'd start there and see if there's enough access. After all, you can get to the maxi fuses that way...

[Enright]

It was definitely a full fascia out job. I was just lucky to have the warmest November day in living memory in which to do it!
While you can access quite a bit with just the switchgear and dials removed, I knew there was never going to be room to get the heater box out through that gap. And anyway, it's as easy to remove the whole lot as to do it bit by bit.

Once you've got the fascia out, there's still the vertical brace that the maxi-fuses attach to which has to come out of the way. And much of the ducting. Even after that it's still a bit of a Chinese puzzle to get the heater/air distribution box out, but eventually it came out as the daylight started to fade. I was looking for clues as to where the water had got in, but there weren't many to go on. The weird thing was that there seemed to have been moisture ingression around the instrument binnacle cover (all of the fasteners underneath it were rusty), there was even some water residue on the back of the instrument cluster, and of all things the steering column was very rusty. I can’t quite work out how it’s come to be so affected by water in such odd places.

With the heater/air distribution box out it was pretty obvious where the water had collected, and it was quite easy to free up the seized controls. I’m just a bit concerned that I may have solved the issue, but not the original problem. In other words I’m going to have to keep my eye on it, or it could return.

The internal flaps that guide the air around the heater matrix or out of the various vents are (or rather WERE) covered in thin foam. But as I tried to clean the assembly up, this foam just fell apart and dropped out at the slightest touch. Rather than have it clog up the heater matrix, I simply washed it all clean away, but think I’ll need to replace it, or it could rattle and clank, which would drive me to distraction! That will be this evening’s job. Then because I’m not fighting the unknown any longer, hopefully it should go back together reasonably straightforwardly. Fingers crossed...

[Fredjohn]

Neil

DIY self adhesive door seal should do the trick to replace the flap seals. With regard to the ingress: try the small foam sleeve/tubular joiner wheel arch duct to heater behind the passenger wheel arch liner. This foam degrades to dust and lets water in: someone else had a similar issue a few months back. The foam sleeve is still available from SJ. Costs about £6 plus VAT plus huge delivery, so only order it with other bits!! Or make your own from thin foam sheet for not a lot.

Lotus part no: A100P0096F page 18.13A of the parts catalogue item 1.

Hope it's this that's causing the problem: otherwise given the rust you've found in unusual areas, perhaps the car spent a long time outside with the hood down and water getting in via the windscreen and dash vents....

John

[dapinky]

.... Or make your own from thin foam sheet for not a lot......

I found that a length of rubber inner tube, split to a flat sheet, wrapped round and held with gaffer tape and cable ties works well.

[Enright]

I like the idea of the DIY solution! And I don't mind the issues caused by the moisture ingress too much, just as long as I am aware of them and can solve any associated problems.

[epipete]

I used a heat resistant foam with a material back that someone sent me as packing once, cheap and easy to locate something on eBay if you don't already have anything to hand.

Looking at the pic I am much more concerned about the leak, and where it is from, I had a leak in my Heater matrix for which, in my ignorance, I paid a local (Corsham) radiator manufacturer a shed load of cash to replace, not knowing that Geoff had a supply (and from whom I later took a spare) of heater boxes!

Since you will need to disassemble the heater box to replace the foam I think you might also want to also inspect the matrix and ensure its soundness. Again, without raising any hopes, I should have the spare that I took from Geoff back in Chippenham (but it's tricky for me to check at the moment!) and if yours is shot then he may have a spare which is more readily available.

When I had my matrix disaster I inspected every part of Coolant system and replaced everything that seemed either dodgy or difficult to get at! My current experience with brakes is teaching me that, unlike in a new vehicle when you have a single item failure and therefore a simple unit replacement here, because we are dealing with component failures in old machines there is multiple derogation to the entire accompanying system; its rather like giving an elderly patient a new heart without cleaning out the supporting arteries.

Pete

[Enright]

I used a heat resistant foam with a material back that someone sent me as packing once, cheap and easy to locate something on eBay if you don't already have anything to hand.

It turns out I had something similar lying around! In fact it was something that Aaron gave me as part of his seat re-trim when I bought the car, so it was good to use a bit of it up. It's only about 3 or 4mm thick, and I simply stuck it onto the various heater flaps with Sikaflex.
A close-up sample of it (and the result) is shown below.

I'd already come to the conclusion that the cooling system was unlikely to be at fault because of various clues that I'd found dotted around the car - damp carpets and rusty outriggers (although that's not uncommon!), the rusty steering column and siezed fasteners under the instrument binnacle cover, and one I'd forgotten about: the cigarette lighter was rusted into the dash!

I've been able to get it all reassembled and back in the car now. I tried it out yesterday. The controls all moved freely so I started the car to see how well the vacuum operated the flaps, and... nothing. Not a peep (or rather a hiss). My first thought was that there didn't seem to be a vacuum feed, so I popped the bonnet, pulled the pipe off the back of the throttle body, and it was blocked! It could have been like that for years but I soon cleared the blockage, and then it worked perfectly.

So the rest of the interior can be put back in, and from now on each job now should be a step closer to completion, rather than just uncovering more "stuff to do".