Fiesta heater problem

snipped-for-privacy@blueyonder.co.uk wrote in news:1159552110.979054.169100 @b28g2000cwb.googlegroups.com:

Thermostat has failed ie. stuck wide open.

Thank you

I`m new to all this what does "end user" v. A command regrettably not implemented in most systems` mean

there is a heater valve on the bulkhead, it is a common failure. Even with a stuck open thermostat there will be some heat.

Mrcheerful mrcheerful

Read the haynes manual about replacing the thermostat. Drain and remove alternator has already put me off, is this really necessary. Would fixing the heater valve on the bulkhead resolve the problem, if so is this difficult.

Dicky

Does the temperature gauge read normal when the engine warms up, and does the engine reach normal working temperature in a reasonable amount of time from cold? If so, forget about changing the thermostat, which isn't likely to be the cause of the problem anyway IMO.

Morse

Draining the alternator is very tricky. You need to be very quick with the Leyden jar to catch all the electricity.

Cheers,

Colin.

Don't worry about it - it's called a '.sig' - a quip or quote that people sometimes add to the end of emails or newsgroup postings along with their name and possibly other contact information.

It's not connected to your post or the answer at all. More like the joky bits at the end of articles in the Readers Digest...

Yes temperature gauge reads normal, engine warms up as it always has done in a reasonable time. Have researched some more and the majority point to the control valve being a common problem, cheaper on ebay than ford so i think i`ll go for it.

Thanks for all your replies, very helpful.

Dicky.

LOL, should have added coolant after "drain"

Dicky

As some of the others have suggested, it certainly sounds like the heater valve. Try putting the temperature setting on medium on put your hand on the valve - you should feel it opening and closing every few seconds - the frequency/period of this varies with the set temperature

- as it controls the amount of hot coolant flowing through the heater matrix.

If you can't feel it then it's bust - when you've fitted the new one you'll feel the valve thud through the car (you'll even hear it when inside) whilst it settles down.

Mathew

"mrcheerful ." wrote in news:9aeTg.26782$r61.5736 @text.news.blueyonder.co.uk:

Surely if the heater control valve was stuck, the OP wouldn't get heat at all? Or does latent heat come through initially? Or am I being thick?

Fiestas of this age have a non-standard system for controlling heater output. The control valve is electrically operated, and pulses on-off-on etc. The pulsing rate is controlled by the dashboard setting.

Oh, BTW, it's a crap idea :-)

Chris

Chris Whelan wrote in news:wBpTg.48611$ snipped-for-privacy@newsfe2-win.ntli.net:

Thanks for that. What a bizarre way of doing it. What's wrong with a cable controlled slider valve?, especially in such a cheap car? Must have been designed by the same bloke who did the C-Max.

Indeed. The only reason for such a system that I can think of would be if climate control was available. AFAIK it was not an option in Fiestas?

Chris

The message from Tunku contains these words:

The only advantage I can see is that the system can be completely sealed, with no shaft-seals. Of course, cars have done this for years anyway, using air-blending heater systems which have the matrix hot all the time but not allowing air to flow through it. I don't particularly like these as they always seem to give out warmish air no matter how cold you'd like it.

Well, strange... but then so too is throttle by wire.

They're old hat.

When they work they allow a lovely precise and fast changing control of the heat output.

There's a mix of reasoning behind it, but the main one is temperature control.

Due to modern engines, the temperature of the coolant can vary quite a bit, even with the engine warmed up (ie it gets hot under load, and then cool of quite abit when off load). By using a solenoid valve controlled via PWM (pulse width modulation - google it if you want to know more), and a simple control unit which monitors engine speed and coolant temperature, it can be programmed to maintain a roughly constant temperature at the heater matrix. I say roughly, because it is an open loop system, and the control unit doesn't get any feedback about the actual heater matrix temperature, it's just using programmed variables to adjust the solenoid operating time.

The other benefit is on the diesel engines fitted with an oil cooler. The solenoid valve is actually a change over valve. Coolant is either diverted through the matrix when the valves on, or it allows the coolant to bypass the matrix when it's off (hence why the valve joins into both pipes), that way there is always a known flow through the oil cooler.

Plus it also saves Ford installing another one of those dreaded cable type things. You know, the kind of things other manufacturers use, and are quite reliable for things like opening bonnets. Which they have in fact used on the latets fiesta, but then again, you could just about get away with putting a french badge on it with not many people noticing....

On the contrary - if you switch from fully hot to fully cold it takes

If this method of control heat output from a hot/cold input was that good then we'd be seeing it all the time in other uses e.g. mixer taps. The fact is we don't - the KISS principle applies.

Besides which, as discussed, the valve is a common failure point and at =A350 a pop from a main dealer it's really something you can do without! You don't hear many complaints from people about their... err.. flaps...

Mathew