[paa100]

Mine does it too. Regulalry. I dont worry about it anymore. But cooling is an issue. Have you noticed that it has a larger air grill than the others MINI's under the bumper........

[paule3]

Quote: Originally Posted by paa100 (original)

Mine does it too. Regulalry. I dont worry about it anymore. .

I'm actually the same, people keep asking me if I've taken it in yet, but I believe we just get fobbed off either way. The only time it bothers me is when there's a funny smell while the fan is going nuts.

[supa-dupa-cooper]

Quote: Originally Posted by supa-dupa-cooper (original)

Mine hasnt done it since

Doh! Im going to stop saying such things!!

Went to get diesel today, pulled up in the garage and there was me thinking i'd driven a MINI not a Hovercraft!! Yup, the fan was on at full whack

The car is going in on Tuesday anyway so might mention it to them as well now!

[Lolance]

Mine's started doing this again

The auto stop/start won't initiate when it's doing it's impression of a hovercraft and the brake pedal vibrates.

Ah well...

[paule3]

Its quite odd, last night I went out into Birmingham and its about a 15-20 mile trip each way but no hovercraft impressions. It only ever seems to do it on short trips.

[supa-dupa-cooper]

According to the service dept its normal Ok then

[paa100]

I only notice it when I stop. I wonder how often its on driving along the motorway...........

[supa-dupa-cooper]

The one on the Cooper does the same

[andrewcregan]

Quote: Originally Posted by paule3 (original)

It only ever seems to do it on short trips.

I have noticed this too. My last 3 occurrences, 2 of which were today, were all journeys under 5 miles .
Never noticed before today, but I can actually feel the vibration from the fan through the steering wheel .
Somewhat embarrassing seeing neighbours heads peering over fences/hedges, wondering what is coming up the road. Imagine the kids diappointment, when it isn't the hovercraft they were expecting to see

[andrewcregan]

Got the infamous 'Hovercraft' impression again this evening. A record 3rd time in one day . Drove about 5 miles at between 25 and 55mph.
Upon picking a pal up they said "What the hell is wrong with your car?" A good question!

[supa-dupa-cooper]

Mine was doing it yesterday, but that was after a long drive, so I expected that, especially as it was quite warm yesterday anyway.

But mine is generally only short journies too, interesting to see that the Cooper also did it after a short journey, but only once in the 4 days I had it!

[andrewcregan]

The most common cause doesn't appear to be anything to do with the outside temperature, but the distance travelled. Reading through this thread, a lot of occurences appear to happen on short journeys - about 5 miles .
What do you think?

[supa-dupa-cooper]

They are mostly short journeys.

See, I was told it was something to do with where the turbo is placed and it being next to/near the pipe that feeds the water/coolant (Im no mechanic ) and where the turbo gets hot it heats up the pipe with the water/coolant (or whatever makes the cooling fan come on). BUT, that cant technically be the case as the Petrol Cooper doesnt have a Turbo Was also told it would be to do with the temperature outside etc etc which I dont believe to be the case either as its not happening at the same temps

[andrewcregan]

Quote: Originally Posted by supa-dupa-cooper (original)

Was also told it would be to do with the temperature outside etc etc which I dont believe to be the case either as its not happening at the same temps

This problem is certainly nothing to do with the outside temperature - my 'Hovercraft' has kicked in between 0 and 17 degrees.
Short journeys are the only thing all my occurences appear to have in common.

[wiggis]

Quote: Originally Posted by andrewcregan (original)

The most common cause doesn't appear to be anything to do with the outside temperature, but the distance travelled. Reading through this thread, a lot of occurences appear to happen on short journeys - about 5 miles .
What do you think?

Poor design IMHO

The engine in the Cooper and Cooper S has an electric water pump. It only circulates coolant around the engine when the engine needs cooling - i.e. when a sensor tells the ECU that the coolant has reached a certain temperature in a certain part of the engine. There will likely be another separate sensor which control when the radiator fan starts spinning - more than likely, that sensor is different to the one which controls the water pump functioning, and is likely screwed directly into the radiator core rather than the engine block.

So on short trips, guess what. The water pump isn't switched on, because the coolant isn't hot enough to require it according to the ECU, but the sensor which starts up the radiator fan, says 'switch on the fan' because of the slow trickle of very hot coolant coming out of the cylinder head.

Seems to me that this would totally explain what people are seeing on short trips. On longer trips, when everything is in thermal equilibrium, then normal rules would apply, and the fan would only run when things get really hot. On short trips, the two sensors are saying different things, hence the strange behaviour of the fan.

[andrewcregan]

Thanks wiggis,
A couple of questions - is the fan justified in coming on?
If not, surely a software upgrade could solve this?

[wiggis]

Quote: Originally Posted by andrewcregan (original)

Thanks wiggis,
A couple of questions - is the fan justified in coming on?
If not, surely a software upgrade could solve this?

If my view on what is going on is right, then the radiator fan coming on within 5 minutes of engine start is probably a red herring and not necessary.

A software fix could certainly be applied to handle this better and reduce the incidence of this happening, however, I can't see a way with the current design of totally eliminating it. As a mechanical change, my guess is that eventually, BMW will reposition the radiator temperature sensor / fan switch lower down in the radiator housing so that it closer matches the engine core temperature. If they did that, my guess is that they would completely fix the problem.

[supa-dupa-cooper]

Thanks for the info there Wiggis

Ah well, im getting used to it now and the strange looks that come with it

[supa-dupa-cooper]

Had a good one today

Went out to wash the car so moved it up the drive a bit, not been touched since yesterday afternoon, and as soon as I started it the fan went off

[andrewcregan]

Quote: Originally Posted by supa-dupa-cooper (original)

as soon as I started it the fan went off

Seriously, this cannot be right