Help identifying under bonnet component

[zederbee]

Hi All,

I have a cylindrical component located behind the coolant expansion tank close to the bulkhead on the passenger side of the car which has started to become noisy.

It looks like some form of pump with a motor inside since it has electrical connections to it and two pipes which look like coolant pipes connected to it, one of which seems to go into the passenger cabin. The other seems to go to some sort of solenoid valve next to it.

Any ideas - I was wondering if it was the additional water pump for the main cooling system but I'm not sure.

Can anybody confirm what it is?

[pingu]

If it is quite small, you are probably right. Confirm it is by ...

ignition on, temp set to full cold = off.
ignition on, temp set to hot = on.

Pump should start to operate when the heater dial is moved off cold, but the sensor can be in a slightly different place on each set of heater controls, but it will be on by the full hot postion.

There is no need to run engine, and I don't think you need to have the heater fan on.

[zederbee]

Thanks,

I'll give it a go tomorrow morning.

[janijoeli]

Number 6 in this diagram?
http://mfans2.com/parts/catalog/Z3-Road ... alve_hoses

[zederbee]

Thanks, That seems to be the part looking at it again in daylight and comparing it with the diagram.

I ran the test suggested and as soon as hot is selected, the unit starts making the noise. I'm due to do a coolant flush so I will get on to my local parts department tomorrow and order a new one. Hopefully it won't be too expensive.