Overheating but fan working...

S

Steve84N

Senior member
I'm looking for ideas as to my problem. As I parked up this morning after a 25 mile drive I noticed that the engine fan was on which made me realise that the temperature gauge had gone up over halfway but not to red yet. The last part of my journey was town driving.

After I turned the engine off the fan continued to run for a good few minutes before turning off. By that time the gauge had returned to the middle when I turned the key to position two but not turned the engine on.

I'm not sure if I had any particular problems warming up as I didn't watch it like a hawk. The car is an 06 3.0si Coupe on 46,000 miles.

I couldn't check the coolant level as it was hot but it was fine last month and I haven't noticed any leaks.

Based on my symptoms does it sound more like the thermostat or a failed pump?

Thanks for any suggestions.
 
As far as I know if the electric pump fails the car will rapidly overheat and shut itself down, so doubt it has failed. there are separate oil and coolant thermostats - if you have INPA you can view these and it might help. Or your coolant could be low, check that first obvs.
 
Thanks Steve, I was hoping it was unlikely to be the pump as it survived a decent journey length with a fair amount of start stop traffic.

I'll check the coolant before going home but hopefully I'll be able to get back without drama.

Good point about the separate thermostats, I'll suggest he checks those first. I don't have INPA and I expect he doesn't either but I'm guessing there are methods to eliminate one or the other?
 
So I'm now in a tow truck after it overheated on the way home just a few miles into the journey. It's looking like the water pump which sucks as I'm already broke from cars.

If I have to replace the pump should the thermostat be done or are they fairly independent and it doesn't necessarily need doing?
 
Sad times, the electric water pump isn't cheap and I *think* they are independent. I don't think it's that difficult a DIY if you want to save some cash.
 
About £325 for the pump and £55 for the thermostat from ECP.

As I don't have a decent way of getting the car off the ground and I'm hoping the labour should come in under 2hrs that's only £100 for somebody else to get covered in coolant and I have to work anyway.

I'm highly unimpressed that it has failed at only 46,000 miles although reading around they have failed earlier...

How audible is the bleed sequence as when I tried the procedure I couldn't hear anything different from when the car is just switched to position 2 on the ignition? I can here a faint noise like a timer ticking but it's slightly periodic rather than constant. That noise is there just switching the ignition on, no difference in sound when I tried the procedure.

Already had to spend a fortune on new brakes and tyres all round on both cars then this tops it all off!
 
Well here's hoping you only need the pump. I have a feeling I've seen them cheaper but cant recall where - google should bring it up. If you can have it fitted for less than £100 then that's pretty good, make sure the bmw coolant is used, it's £10 for 1 or 1.5 litres that dilutes to double that.
The pump should be a strictly mileage based replacement but I suppose as they age and with low miles they can fail prematurely.
On the plus side it will see you right for a good while.
 
Do you know how much coolant I need to get from BMW, I've seen 2 gallons mentioned elsewhere so 3 bottles of 1.5l?
 
Garage also believes it's the pump so hopefully will have a new one fitted by tomorrow evening.

BMW say about 8l of coolant so it is three bottles.

The garage seem to be using the internet just as much as I am when I talked to them about whether to replace the thermostat as well. Shouldn't be necessary though is the conclusion.

It's got me worried about the N52 in our 330i Touring though...
 
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