Right after a loss of heating to the other halfs fiesta I ran through the basics. Heater valve was faulty so replaced, discovered thermostat was stuck open so replacef that, flushed out the matrix and the rest of the system. Started the car and got only warmish air coming through. Checked for pulsating voltage at the heater control valve and all is good. Really I'm at a dead loss as to what else is stopping the car heating from getting warm. My other half wouldnt mind but shes just had a little one and I really dont want her driving it around in the cold snaps without heating. On a side note I've also bled the system best I could and believe all the air is out of the matrix and pipe work.

Thanks in advance if anyone can help

Sounds like a air issue assuming the car reaches its working temp and circulation ok. I have a 2004 1.4 19k great heater.

Update. So today I completely re flushed the system and filled up with new coolant. Still no hot air. Water into the heater matrix is roasting hot and the return feed is onlu warm. If I disconnect the return hose I get a nice steady flow of hot water and warm air in the cabin as soon as I re attach the hose the air goes cold. Now that return pipe leads straight back to a branch in the bottom hose near the water pump. Is there a chance this hose could be.partially blocked thus not allowing a good flow through the matrix. Altho I thought if this was the case the engine would overheat. The only other thing I havent tried is completely bypassing the heater control valve and seeing what happens.

Any suggestions at this point would be great as it's driving me crazy.

Yes it could be blocked and wouldn't overheat as only same effect as turning the heater control to cold.

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How did u flush the matrix

Used some rad flush and let it soak for half a day then flushed it backwards and forwards with the hose. Got no end of crud out of there. I got it clear to a stage where I could fill it with water from the top using a funnel when before I started I couldnt even get anything in there at all. I was looking aroumd to see if I could find the matrix capacity so I could check it's holding what it should.

If you get warm air and water from the return pipe when you disconnect it then it sounds like the matrix is ok I would have thought that it is somewhere along.

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I would buy domestic household rad flush remove thermostate an drive for 2 hours always works for me

Return hose sounds dodgy.