hot n cold blowers

[dom_e]

Driving today the blowers began to blow cold when set at 31. First thought was we had a coolant problem, but the alarm hasn't sounded and the gauge was constantly at 10ish (not modified). We've not had cause to top up recently (since the hoses were changed a good few months ago, it's remained steady). Increasing the temp to 32 results in very hot air. Air con was off.

I'm concerned since the last time this happened, the water pump was leaking. No obvious sign of an issue, so does anybody have an idea...am I being paranoid?

The road was the hilly a470 through Wales for about 3hrs.

[Simon Jones]

I find that one degree change on the controls makes a big difference in temp from warm to very hot. Only observation is that 10 o'clock on the temp gauge seems a bit low as it typically tends to sit around 11 o'clock when up to normal temperature. Does it take a long to warm up? That might point to the thermostat being stuck open or a bit lazy.

[dom_e]

It doesn't seem to take too long to warm up. I think the stat was changed with the water pump a few years back. 10 on the gauge may be a bit ambitious; maybe it was more towards 11.

The temp control always seems to have been a little...unpredictable, but this seemed like a particularly stark case. Towards the end of the drive on less hilly areas, it seemed to be more stable.

Is there a control flap or mechanism that directs outside air more or less across the heater matrix? I wonder if that could be a bit sticky?

[cmm303]

I can't remember but is 32 the max temp. ? Is so I believe this setting ignores the cabin temp sensor whereas any lower temp setting monitors the sensor.

[g8dhe]

Yes at the extreme end when it displays 32 the fan is driven at full power and the servos' select max. heat settings it then ignores the reported cabin temperature.

[mikeWalsall]

A common problem is the metal adjusting rods coming out of the heater / flap ..