Hi people, I've been googling around a lot regarding my heater problem and can't seem to find anyone with this issue:
Basically, about 18mths ago my heater went hot regardless of the setting on the dashboard. After about a week it was suddenly cold; again with no ability to get it hot. I never did anything about it until about a month ago.
After searching it seemed the problem was a faulty heater control valve, so I got a new one off eBay for about £20. Got this fitted and all was fine- for a week.
Then, it seemed to get stuck on hot again and I couldn't get it to cool down. However this afternoon I noticed something really odd. I could put the control knob in any position and it would make no difference to the following: if the engine revs were low (ie ticking over), the air blew cold. The higher the engine revs, the hotter the air got. I literally tried sitting in traffic revving it in neutral and within 15 secs it was roasting hot. Let it tickover again and within 15secs again it was back to cold (properly cold, not just a bit colder than hot). Tried again and again and the result was the same.
Do you think I've ended up with another duff valve? I've seen on the internet that people seem to have problems with OVERheating after fitting a new valve; why?
I haven't tried bleeding the coolant to remove any airlocks; will try tomorrow.
Any suggestions? I'm ready to drive this car into a canal tomorrow if I don't fix this problem once and for all!
Thanks, Simon.
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Jump out before you go in the canal simon!!
Is the temp gauge showing hot/cold at the same time as the heater?
You could try a new thermostat and bleed, fitted one to the wife's ka not a bad job to do.
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lol, will have to time it well! There's no temp guage on the car, I assume only a warning light if it starts to overheat; which has not come on so far so I assume the engine temp is ok. Having just a few seconds ago looked under the bonnet, I think there is too much coolant in the tank as it's above the maximum levels. Maybe this could be the problem? I think I filled up around about the same time things started going wrong- so it does seem likely.
A mechanic said I might need a new thermostat too.
Thanks for the response! Will try and remove excess coolant and see what happens.
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Simon, When running is the coolant in the tank bubbling? best to drop to max mark to allow for expansion or it can blow a hose,
I'd try a new stat for the sake of a few quid get a new gasket and bleed then try again, ok on no gauge neither does the ka just tells you at the last minute you have problems thats if the light works!!
Try flushing radiator just put hose pipe up it clean out any crudd, see how you get on.. good luck,
The canal can wait.lol!!
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Cool, might try that. I got the extra coolant out so now it sits between min/max when cold. Drove for only about 2 miles with hot setting on, and cabin did not show any sign of heating unless I revved as before. Had a look under the bonnet and all 3 pipes coming out (ie going towards the back of the car) of the heater valve are hot- which suggests the problem might be the heater matrix I think?
Oh and there was no bubbling of coolant, so I don't think theres any airlock.
I will test to see if the voltage is pulsing properly tonight or tomorrow.
Thanks again!
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Hi guys. My heater valve broke a while ago so I was stuck on cold, swapped it for a new one and now I have heat again but it doesn't work right. If I'm just sitting at tickover when the engine is warm, the heater will go hot and cold correctly using the knob. If I start actually driving though the heater starts to blow hot air even if the dial is set to cold. I've tried pulling over and then it goes fine again as long as its only ticking over. Same problem happens again when I start moving.
Anyone seen this before or can suggest anything?
Thanks!
Si
{moves to previous question asked as related problem}
Edited by Dynamic Dave on 10/04/2008 at 19:48
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Si
I've seen countless faulty new heater control valves that stick half way.
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Sorry I didn't realise I'd posted this back in my old thread. Thanks for your response again screwloose! This is actually the 2nd swap I've done now- I had the original one stuck on cold, switched for a new one which behaved as this is now and I have again switched to a new one (so I'm on 3rd one now).
So you reckon it's just dodgy valves again? I thought it might be but thought statistically the chances of having 2 faulty replacements consecutively would be unlikely.
Cheers.
Si
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Si
Depends where you got them from - some of the stuff on e-bay isn't the best quality......
The control panels can go too; the only way to check is to get the variable pulse signal to the HCV on a scope.
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"Sorry I didn't realise I'd posted this back in my old thread."
You didn't it was moved there by a kindly Mod.
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Ahh, cheers Pugugly.
When I replaced the last replacement (i.e the 2nd valve to ever go in) I plugged the new valve into the electricity and started the engine; switching between hot and cold to see if it changed- and it did. On cold it was not moving and half way it was pulsing back and forwards- but I admit it didn't look like it was sealing properly to me but I wasn't sure what it should look like.
After I'd got the broken one out I did that same test and it was jammed half open, so that one was definately broken.
I bought it on eBay but the guy is an official business (www.transitparts.co.uk/ ) so I would expect good quality- in fairness to him he's now sent me a third replacement to put in. I'll swap them over again soon and see if it behaves differently before I actually put it in to see if it looks like it seals better.
Cheers for your help again!
Edited by Dynamic Dave on 15/04/2008 at 16:38
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Latest news: got a new valve today. Plugged it into the car's electricity but not the actual pipework so I could physically look inside the valve as it operated. Definately moves in and out correctly with hot/cold setting; however I tried a little test myself by pouring water into the pipe that coolant would usually flow into. It seems that the valve is not properly sealing because when it's set to cold a bit of water seemed to be leaking through into the pipe which it shouldn't be going through which explains why it's still making the cabin hot even on cold. I must admit though it didn't seem to be much leaking through but this was just with water poured in from a bottle, I imagine that the engine coolant will be flowing much faster at higher pressure and so more is getting through.
You guys reckon this is the problem? Should the valve be sealed so much that nothing gets into the wrong pipe?
Thanks again.
Si
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HELLO THERE. I've had some expierience of heater problems on these electrically managed controlls,with different solutions .Here are some: a /motorized valve faulty b/heater controlls faulty(these aren't just knobs) c/crankshaft angle sensor faulty (don't laugh) ,this does help regulate ; coolant flow varies with engine revs.Please note as these fiestas don't have temp. gauges ,just ask a garage to check your engine running temperature (2mins).If the whole system is running too hot or cold, the heater will never function properly.Also be aware that your heater may even be blocked (check the flow).Hope this helps...........
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Thanks for your advice: in the end it turned out I had ANOTHER dodgy valve, got a new one and it's been fine for months. Until now...lol.
Now it seems generally to be ok until I've been driving for a while (30+ mins) then it seems to be blowing hot constantly; unless I drive fast (60mph+) then it behaves as normal. I'm wondering if this is an engine overheating problem? I've noticed recently that I have to keep topping up coolant more often than I think it is normal to do which makes me wonder if I have a leak somewhere which is causing this.
Anyone ever seen this before?
If I'm honest I was driving on the M40 once and a wooden stake got whipped up by the car infront of me and (statistically so unlikely) hit the front grille of my car and hit so perfectly that it lodged straight through and into the heatsink (I actually forgot to look when I stopped driving and only noticed the next day that I had a 1 foot long stake pointing out of the front of my car! lol). I checked for damage and it looked as if the rad was untouched, there was a slight mis-shaping of the 'waves' of the heatsink though.
Thanks,
spuk87
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