Odd coolant problems (M40)

[Zayyan]

Hi all, my M40 takes ages to heat up (therefore interior heaters are cold for a good few minutes after starting) and doesn't reach normal temperature (the middle of the guage) unless driving slowly or being stopped and idling (this means that on long motorway journeys the needle is constantly around the 1st quarter mark).

However when idling the temperature starts to rise slowly up to the start of the red area (at which point I get scared and turn it off).

I know that the user manual says that the needle can reach the start of the red area during normal driving but I'm pretty sure that it'd go into this area if I left it running

Any ideas?

And yes, the coolant is filled to the correct level.

[Brianmoooore]

Nothing odd about this! Just that you have two seperate problems.
Number one - You nrrd a new thermostat.
Number two - You need a new viscous coupling.

[Zayyan]

Thanks Brian, would you be able to elaborate and tell me which item is causing which problem? Cheers

[Gwynleym10]

The thermostate is stuck open, meaning that coolant is always passing through the radiator. This means the car never heats up properly.

Viscous fan is not engaging so when the car is stationary, the water in the radiator never cools down, meaning that it get hotter and hotter

Neither are that hard to sort.

Why don't you try an fan of one of your other m40's to sea if that makes any difference

[Zayyan]

Thanks Gwyn, will give that a try on the weekend.

Sitting in Bristol City Centre traffic is a stressful affair at the moment (though it does give me an excuse to go the long way round )