Fiesta - no heating - tried the obvious

jimexbox

Hi

I hope someone can give me a few pointers.

Since the end of last winter I've had no heating in my fiesta 2001 1.8tdi. With winter on the way I decided to sort it out.

I've done the obvious first, I changed the notorious heater control valve. I checked the new valve (original ford) before I fitted it by altering the temperature setting inside the car, and blowing into it while blocking the other connectors. It pulsed fine through the range, and was fully open when the temp control was set to fully open.

At the same time I drained the coolant off, and filled up with fresh. I bled the system and topped up. Still no heat, damn! I got a spare heater control unit, so I popped the radio out and connected that up, still no heat. The control valve pulses fine with alternate control unit.

I decided to remove the valve altogether and join up the relevant pipes with suitable size tubing. Low and behold I get nice hot air, although it seems to be rev related. Very hot when I rev in neutral, heat drops off when I idle, although its still warm.

So I put the new valve back in. No heat!! Arrrggg! If anyone can help it would be most appreciated. The car has never overheated, even in summer in heavy traffic. Though their is no separate engine temp indicator.

Any ideas?

darich

Years ago I had a Vauxhall Cavalier with a dodgy thermostat. It wouldn't open if i remember correctly. So as a temporary fix I driled a couple of holes in it to allow the water to circulate and prevent overheating.

Could it be that your thermostat is jammed open so the water takes much longer to heat?

If the thermostat is stuck open then the water will circulate right from the minute the car starts rather than build up heat around the engine. As a result it'll take ages longer for the car to warm up. That could also explain your "never overheats" problem.

I'm no mechanic but that's from my own experience.

jimexbox

I did think of the thermostat, but when I bypassed the heater control valve (which works) I get hot air. Very confusing as the water circulation system is pretty basic.