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Heater on full
Posted: Tue May 20, 2014 11:31 am
by 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.
Re: Heater on full
Posted: Tue May 20, 2014 11:35 am
by 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
Re: Heater on full
Posted: Tue May 20, 2014 11:40 am
by DougWomble
Cool, that sounds quite feasible - I'll take a look at it now...
Cheers dude!
Re: Heater on full
Posted: Tue May 20, 2014 3:50 pm
by 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.
Re: Heater on full
Posted: Wed May 21, 2014 9:32 pm
by 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
Re: Heater on full
Posted: Thu May 22, 2014 3:55 pm
by 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

Re: Heater on full
Posted: Thu May 22, 2014 4:00 pm
by 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.
Re: Heater on full
Posted: Thu May 22, 2014 4:13 pm
by 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.
Re: Heater on full
Posted: Thu May 22, 2014 4:15 pm
by DougWomble
Of course - I'm being particularly dopey today. Thank you.
Re: Heater on full
Posted: Sat May 24, 2014 10:57 pm
by 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 :-/
Re: Heater on full
Posted: Sun May 25, 2014 7:21 pm
by 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?
Re: Heater on full
Posted: Sun May 25, 2014 9:05 pm
by 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.
Re: Heater on full
Posted: Mon May 26, 2014 10:29 am
by 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.
Re: Heater on full
Posted: Tue May 27, 2014 4:56 pm
by crashbanggg
Just replaced it, easy enough and now nice and cool!