My vrs heater used to warm up quite quickly and more to the point, the actual amount of heat delivered was easy to control and it was a rare event to have to adjust during the winter once a comfortable setting was found.

After the cambelt / water pump renewal I have noticed that any heat takes nearly double the previous time to filter through and is then far too hot for another mile or two. After that it does settle down to a sensible temperature again. However, it is now a very fine line between heat and no heat at all!

Would the thermostat have been disturbed, or replaced, on the above repair? The bill certainly doesn't list a thermostat in the "parts used". After a couple of days following the above work I did notice that the coolant dropped, possibly due to air bubbles. The coolant is not leaking out on the garage floor.

Thanks for any thoughts on the problem

Peter

Sounds like a coolant air lock. Bleed coolant system to remove any trapped air.

The cooling system shouldnt air lock, the Fabia has a nice high return so should be fine.

Id have a quick dianostic check of the flap motors, might just be a coincedence.

Being unable to see anything obvious, I decided to run the engine inside the garage with the pressure cap off the expansion vessel until I could see that the coolant was warming up. I didn't know what to expect, or whether this would do any good, so was very pleased to see lots of bubbles on the surface in the first 2 minutes.

After a couple of minutes it seemed that just coolant was being pumped back, so after around 5 minutes switched off and replaced the cap.

Surprise, surprise, it was a lot better tonight on a 12 mile journey. I set the heat control on a sensible level during the outward journey and left it well alone on the journey home 4 hours later. After 1 mile heat was detected coming into the car, and no adjustments were required at all on the homeward sector. Hopefully it will get rid of any remaining air by itself now. Many thanks for the advice offered.

Regards

Peter