Ford Fiesta 2001 - Heater Control Valve

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Sat 19 May 2018 19:54
Ford Fiesta 2001 - Heater Control Valve - Headfirstfail

Hello!

So my 2001 Ford fiesta was only blowing hot air, and after a bit of research I decided to replace the heater control valve.

So, I drained coolant, replaced valve and then refilled coolant.

The good news... I now have cold air and cold aircon!

Bad news... I have yet to get hot air through and the car is overheating. Sigh.

So, I realised I'd made an error. When filling the coolant tank back up, I left the lid off while running it to 'burp' the system. None of the coolant was flowing and the car was overheating very quickly at idle. and I was left stumped. Having talked it through outloud and ingesting some well needed caffeine I realised that with no vacume it wouldn't flow through the system. So, I replaced the cap and ran the engine. The coolant went down as expected and I topped up a couple of times. No longer an overheating car! (woohoo)

With lovely working air conditioning and cold blowers, I finally sat back feeling happy. Having left it for an hour, I've then gone to drive and hot air is back! It is all I have.

Any ideas on this one?

It's worth mentioning that when I bought the car the coolant was empty. And there is a very small leak. And when I say small, I mean less than a few mls!

I'm slowly going insane!

Thanks!

Edited by Headfirstfail on 19/05/2018 at 19:56

Reply | Report as offensive | Link
Sat 19 May 2018 21:22
Ford Fiesta 2001 - Heater Control Valve - elekie&a/c doctor

Firstly,it is not neccessary to drain the cooling system when changing the heater valve,otherwise you will experience problems bleeding the coolant system to regain hot air.(as you have found out).The circuit to the valve 2 pin plug needs to be tested. With ignition on,one of the wires will be live 12 volts.The other wire is the earth return control wire back to the heater panel on the dash. You really need a digimeter to check the voltage at the 2 pin connector.This should alter as the hot/cold control is moved..If it doesn't,then i would suspect the heater panel is goosed. Have no fear,a new one from Ford is around £400, so s/hand is the way forward.

Reply | Report as offensive | Link
Sat 19 May 2018 23:26
Ford Fiesta 2001 - Heater Control Valve - Headfirstfail

Thank you for your reply, I appreciate that.

I'll check the plug ASAP and cross every finger that it isn't the heater panel!!

Thank you!

Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide