C5X7 Heating Momentarily Cools

[PeeBee]

Hello All,
For the last 3 or so months of the cold weather I have noticed a strange phenomena with my heating. I'm having no problem with it as I write and rarely am I able to stand it on full heat but I notice that when I slow down, say to negotiate a left hand turn at a junction where theres no need to stop, the heating noticeably cools for 3 or 4 seconds whilst the vehicle is in the turn, not to the extent that the fan blows cold but it definitely cools until the vehicle takes up its normal straight ahead line of travel and then the heat returns to its normal level. Its as though centrifugal force has momentarily forced the water coolant out of the heater matrix for a few seconds but I cant see that.
Anyone else noticed this and what could it be ?. . Ive checked the coolant level and its up to the maximum in the reservoir.

[Hell Razor5543]

I wonder if the pollen filter is getting blocked?

[GiveMeABreak]

That won't affect the heating, just the air quality / smell and possibly some slight air flow impedance if really soiled and clogged, but won't affect hot and cold temperatures at all.

The only thing I can think of is a reduction in electrical power. Power steering is electrically powered and would take more power when used in a turn, then depending on what else electrical you have on (High Heating - which may be using the cabin heating resistor to provide supplementary heating, heated rear window, USB devices, Head Unit - lights if at night, etc etc.,) so may be related more to the available power supply.

This could be accentuated if you have a slipping or loose accessory belt, or the alternator isn't charging as much as it should, poor leads to the battery ..... any of these things could cause a power drop until the engine is going at speed again.

[PeeBee]

The pollen filter was renewed about 2k ago and the vehicle is only used on public roads. Ive noticed this cooling effect in both day and night time driving and I dont perceive any voltage drop i.e. headlights dimming or a drop in the sound of the heater fan but then I may not hear a specific sound reduction as the fan is always on low. Ive recently replaced the battery but admittedly the vehicle doesnt do enough mileage to keep it fully charged although I havent suffered a flat battery but the low voltage sounds the most feasible. I will pay more attention to that aspect over the coming weeks and see what I might detect.

[Bandit12]

Hi all,

My X7 does exactly the same and has done so since buying it 3 or so years ago. i have also tried the usual suspects of changing pollen filter and battery. lights on/opff seems to make no difference. I had same problem on my old mk1 C5. I read on this forum some years ago that the splines on the heating flaps were not well made and/or fully engaged so when you go round a corner the flap is able to momentarily jump off the splines and close the hot air supply. its only really noticable in winter when heating is on full. I wonder if this is the same?