Heater on full

[DougWomble]

Hopefully this all makes sense - my car's a furnace right now. I knew the heater was full on in the winter - this was fine - but now we're approaching summer it's not so amusing.

I thought I'd found a solution elsewhere online, but I was wrong. Therefore, I'm thinking it's one of three things:
- Fuse has gone (ruled that one out now)
- Physical problem in the unit (but can't seem to find anything)
- Something has got borked under the bonnet, meaning I can't get any cold air in (as I say, I thought I'd found the solution online, but turned out to be something unrelated).

Does anybody know where I should be looking, as I'm melting here?

TIA.

[bengould]

Your heater control is cable operated not electric. There is a bike brake style cable that runs from the controls on the dash to a valve under the bonnet. Check the wire and also the valve. If either is damaged the heater will stick on/off.

Ben

[DougWomble]

Cool, that sounds quite feasible - I'll take a look at it now...

Cheers dude!

[go-for-it1]

Mine was like a furnace too then I bought a new heater valve and now cool. Easy to fit just 2 clips and the cable clip and if you are quick you dont lose much coolant either. Dont get a second hand one as they are usually duff and they are only about £8 new from GSF.

[mark1gls]

The valve looks like this, 1st check the cable/wire has not come off the end of the valve as it's just bent on then check the valve moves, it works by shutting off the water flow into the car.
http://www.ebay.co.uk/itm/Heater-Contro ... 5d42f7e821

[DougWomble]

^ All very interesting.

As it is, the cable is still on the end of the valve. I can manually switch the valve on / off also.

However once inside the car I can turn the heat on (with the valve doing its thing), but trying to turn it off again the valve doesn't shift back across. I've sprayed it with a bit of WD40 in the hope it unsticks things, but unless someone has a bright idea I'm going to have to get a brew, stare at the thing for a few minutes, and think things through logically.

Don't you just hate getting stumped by (seemingly) simple things

[marcus]

Cables can usually only pull, so is there a spring inside the valve which returns the valve to the closed position when the cable tension is released? If so it could be the spring has broken.

[GTXTRA]

Yes. Cables might work fine but the valve itself can fail.

New valve an easy thing to fit especially on carb cars with easier access.

[DougWomble]

Of course - I'm being particularly dopey today. Thank you.

[Nate]

it isn't a cable, it's a very thin rod. this means that it can push and pull. a common failure is that the cable will kink at the lever end. when you try and put the lever back to cold, the rod just kinks and the valve don't move. easy to diagnose, watch the valve while someone operated the lever. i've had the same problem on several volkswagens now. on my caddy i managed to carefully heat and straighten the rod so it worked again (removed from the car first!!) but on the rocco i think it is too buggered. failed to source a replacement as yet too :-/

[crashbanggg]

Iv got the same issue on mine, iv got a new valve ready to go on, am I right in assuming it's just the following two clips to undo?


And when I pull the pipes off, will I be expecting fountains of coolant or just a little dribble to come out?

[go-for-it1]

Yes to the pipe clips and no to the fountains, so long as you don't do it after a run or when hot, and leave the cap on the reservoir whilst you do it to prevent air getting in which minimises the amount of water coming out at the heater valve pipes.

[mark1gls]

You will also need to remove the clip which holds the cable to the valve as the new one does not come with one and make sure you put the cable back on in the right place, you will need to check this by sliding the heater control from hot to cold and make sure valve opens and closes.

[crashbanggg]

Just replaced it, easy enough and now nice and cool!