CAN SOMEONE PLEASE HELP WITH C5 HDI TEMPARATURE GAUGE PROBLM

[scarletassassin]

Hi I am having problems with my C5 estate HDi, 02 plate......start car up driving along and the temperature gauge on the dash board goes down to the 2 cold markers then slowly returns to the middle of the temperature gauge ....and just repeats the down to cold back to middle.

When I have the blowers on they are blowing hot air then sudden blast of cold air......the mechanic is just taking random shot at what it could be and is basically costing me a fortune in these random shots. Thermostat has been changed and 'k-seal coolant leak repair added - and is still doing the same and not made one bit of difference to the symptoms!!!

Really puzzled because its been fine up until now surely this isn't unique.

[Mandrake]

Sounds a bit like an air lock in the cooling system... has the cooling system been thoroughly bled ? I can't see why the mechanic would add a coolant leak repair additive if there were no leaks ??

[addo]

Bienvenue! Aviser svp votre région, pour aider à localiser une personne compétente.

[citroenxm]

Does the heat from the heater change at all or does it stay at the same temp???

If SO, then it is the Temp sender in the side of the thermostat house, I had one dooing all sorts - over heating cooling etc.. swapped the sender (the only one, its below the intercooler pipes, on the side of the head above the gearbox) and all normal service was resumed...

I had also done as you, thermostat, rad etc etc..

[Mandrake]

Does the heat from the heater change at all or does it stay at the same temp???

The way I read the original post is that the heater IS suddenly going cold when the reading drops, thus suggesting an air lock in the cooling system, potentially a serious one that could do some damage if not sorted out...

[citroenxm]

Yes of course Simon... very serious ...