Overheating E86

[Homer]

Afternoon,

On a short trip out the car started overheating yesterday. It was quickly tuned off cooled down and managed to limp it home. I've checked and topped up the coolant took at another run today to see if the problem returned and it did. I've noticed I'm not getting any heat at the blowers.

Has anyone had a similar issue? My guess is an air pocket or blockage in the cooling system? I can see water/coolant has leaked from behind where the coolant is topped up and there is a small puddle on the under tray.

Any advice?

[enuff_zed]

Not an N52 expert but I believe the most common issue with them is failure of the electric pump? Check that first

[Homer]

Pump was replaced year and a half ago so shouldn't be the pump

[Smartbear]

As above, suspect the electronic water pump - they’re usually on thin ice once above 70k miles. If it’s working you should see a flow of water at the top of the reservoir where you can check the coolant level.
Rob

[enuff_zed]

Pump was replaced year and a half ago so shouldn't be the pump

Shouldn’t be, but never discount it just because of that. I would have said expansion tank split or the seals between it and the hoses but your lack of heater sent me in the pump direction. Not sure how an airlock would suddenly occur if it’s been ok?

[Mr Tidy]

Although you've had a new water pump what you describe suggests a failed pump is the most likely problem.

Probably worth getting the fault codes read as a dead pump should show up.

[SteVR]

What engine? If its a N52 scan for codes, water pump if failing should throw a code.
Not sure on the Z4 but with my old 130i theres a specific bleed procedure with these pumps.

Turn on the ignition (do not start), set heater to maximum and fan on the lowest setting. Press the accelerator pedal to the floor for >10 seconds. Release the accelerator pedal. You should hear the pump running as it performs the procedure, takes a couple of minutes.

[Homer]

Looking like water pump and again, curent one was replaced in June 2020 and the car has only done 12,000 mile since then, it will be interesting to find out why it has failed so soon after being replaced.

[Joycey]

Looking like water pump and again, curent one was replaced in June 2020 and the car has only done 12,000 mile since then, it will be interesting to find out why it has failed so soon after being replaced.

Worth checking to see if it was replaced with a genuine peirburg unit, others tend not to last very long.

[Homer]

The car has been picked up from Joni and his team at Glasgow Independent BMW & Mini and thankfully hasn’t needed a new water pump problem has been due to corroded wiring which was needing replaced.

Bad news is I have an oil filter gasket needing replaced and faulty ABS sensor module so they’ll be looked at in February when it is in for a service and mot, always something needing done