Cabin heat not working

[Loach1]

On my S1 I can only get hot air out of the demist vents, nothing when set to cabin. It won't be an issue soon, but it would be nice to fix it. At some point the eyeball vents have been connected to the heater, and the fresh air hoses deleted. I can't see but my assumption is that they are connected to the PVC pipe on the heater.

Can you guys tell me what the cabin/demist slider moves? It is connected to something because when I select cabin the demist flow reduces and the air noise increases, but no air comes out of the vents.

I wonder if I will miss the fresh air in the summer? I don't plan on using the roof, but it can get silly hot!

Thanks,
David

[Loach1]

Haha!! I think the heating design engineer was high on Blackpool rock! I had a peek behind the covers and found the problem:

I thought it was just damaged, but some poking about revealed that this is likely to be the original design. There is just one hose that goes to both vents, positioned and originally taped around the heater cabin outlet. Here's the outlet area from below:

I think the best bet is to attach a PVC pipe with some good glue and go from there.

Has anyone else improved this? I don't want to reinvent the wheel.

[v8s4me]

Try using the flexible pipes off a hoover. These are smaller in diameter than the original plastic tubes so they'll slide inside them and can be sealed with some gaffer tape. They are also much more flexible than the originals so you'll be able to route them more easily. Looks like the same bloke did yours as did mine. On My V8S one of the plastic tubes was 6" too short and so could never have been connected to anything - it had just hung there wafting warmish air into space for 20 years!

[swimmer27]

My 1989 S2 only delivers warm air to the windscreen and nothing to the cabin, isnt this the norm?

[S2Mike]

My ducting is too short to reach the eyeball vents but it does blow a good amount of warm air into my nether regions which has been very nice these past few weeks, unfortunately the windows steam up and my hands stay cold, especially with the chrome gear knob. I have to take it in turns to sit on my hand or stick it under the dash to thaw out. I have to open the bonnet to alter the heat though as the quadrant appears to be siezed, but plan to upgrade to the vacuum pipes, as per V8s4me.

Edited by S2Mike on Monday 4th March 12:42

[Top Gear TVR]

my s2 works as it should including a dash out new heater core, which was easier than anticipated!

But it still leaves room for improvement;

Demist and footwell adjustments are by a cable operated flap which if connected to the lever and the heater box should work fine.

I just wish there was a bit of natural air-forcing heat through when on the move without the need for the fan. unfortunately the design doesn't do this and only allows recirculation of air by fan - which is a shame in January and December when you need lights, wipers and fan on and it takes all the alternator can give.

One day I might come up with a natural air feed solution allowing delete of the fan in all situations except standing traffic. I am thinking of a forced feed to the fan intake or similar,probably stolen from the left eyeball..........

one day

[phillpot]

Loach1 said:

Can you guys tell me what the cabin/demist slider moves?

It moves a flap within the heater "box" to direct air either to the screen or to the flex ducts. The problem is it doesn't close off the screen completely ( an intentional design to keep screen clear?) so the vast majority of air still takes the easier route, to the screen rather than down a few feet of contorted hose!

It's a bit of a job to get at the heater but easy enough to modify the flap and replace any perished foam seals etc. once its out.

Just noticed you have an S1, things may be a little different to my S3?

Edited by phillpot on Monday 4th March 11:33

[Top Gear TVR]

my s2 is the earlier dash, which to be fair was a doddle to get out compared to previous mercedes 190e experience.....

[Loach1]

swimmer27 said:

My 1989 S2 only delivers warm air to the windscreen and nothing to the cabin, isnt this the norm?

I believe the norm is to have two hoses dangling in the footwells that blow warm air when the 'cabin' is selected.


I will get some 1.25" vacuum hose and create something to go from the heater outlet to the two hoses, then connect them to the eyeballs.