XSeries-forum

My 4.4 is running way too hot, so figure the first place to start is the stat.

Called ECP and GSF, neither of whom had stock, but could get one by Monday - cost £13.50 plus VAT.

Called BMW, who want £95. Really? What's it do that the others don't? Guess they don't sell many thermostats!


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hate to scare you but a faulty stat should stick open, so would not overheat the car

That was my thought too.  Pretty rare for a stat to jam shut.  Any sign of water loss, oil in the water?  Pressure cap working OK?  How does the expansion tank level look between cold and hot?

BMW parts are all made of special metal alloys called Breakmywalletium......

Oh and

on a 328i i had way back the waterpump went and the car was overheating

Bought it six weeks ago an they'd just replaced the water pump, so don't suspect that.

Coolant level is good, right colour, no odd smell.

Could be an airlock I suppose, but it never actually overheats, just seems to run at about 105C which to me is at least ten degrees too hot.

Even smells hot after a decent run.

Electric fan doesn't kick in, though I'm not sure what temp that would be - I'm sure it's different to my older E39.

Any suggestions for things to check? All my experience has been with the straight sixes, not the V8.


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That might be the problem.  The electric fan should be running so my guess is either a knackered fan or sensor that turns it on.  One of the V8 brigade will know where it is.  Could you have left a wire off?

What about the viscous fan?  Is that OK.

The engine is supposed to self bleed but you might get an airlock.  Does running the A/C cool the engine any?

Electric Fan spins freely, could be the control. I've not touched anything so if a wire is off it wasn't me!

Viscous. Hmm, haven't tested whether it's locking up - good nudge.

Saying that, the motor shouldn't need that whilst driving at 50 in free air surely? Maybe the engine bay of the V8 is too full for motion to shift enough air without the fan...


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What about this no14: http://www.realoem.com/bmw/showparts.do ... g=64&fg=18

going on that my e46 m3 used to go up to 3/4 and on a hot summers day towards the red, that was the electric fan on the front of the rad, it span freelee etc, i just chanced it and bought one and waited till car got hot, jumped out and pluggged it in and the new one was spinning so i then fitted it, couldnt just test it as it goes through some sort of module first on m3

[quote="X5Sport"]
  Pretty rare for a stat to jam shut. 
[/quote]

I had two in as many months on my 4.4.
[quote="Dave ett"]
, just seems to run at about 105C which to me is at least ten degrees too hot.
[/quote]
That's actually bang on for the 4.4. The standard stats are 105 degrees, so I think your looking for a problem that isn't there (yet) getting a replacement will be exactly the same.
A lot of the v8 guys go for a cooler stat. either a kit part one that runs at 80 degrees or a diesel one at 88 degrees. Mines now running a 80 deg one and feels a lot smother and actually improved mpg. I know there will be purists saying this is wrong, but for the peace of mind that leeway gives you and the better running, its an easy choice. Ive got a spare 88 deg sat on my printer if anyone is interested?

The electric pusher fan should kick in at 100 degrees to help the viscous  when airflow is low. They self test when you switch the engine on. Get someone to start the car whilst you watch the fan, it should spool up to a medium speed for a few seconds.

Really interesting info there.

The needle has sat dead centre throughout, and it's only because in the Dynavin & 'secret' menu I can tell the actual temp. It sits firmly at 110 and doesn't creep any higher, which correlates with you saying it should run at that temp.

Saying that it does smell hot, and just makes me wince to see it that hot!

Why's odd is that the temp readout drops 5 degrees when the ignition is switched to pos 1.  Go back to 2 an it goes up 5 again ( engine not restarted).

Lekkie fan hasn't kicked in at all yet, even with air-con on and engine at 110. Maybe ambient is a bit cool to trigger it.  Will try the self test thing.

Would def be interested in the 88 thermo... Price?


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If the electric fan does a little dance - swinging back and forth, then It's fair to say it's shot. They do throw a code though when they go so get it read or by yourself an interface with a copy of inpa to Check these things out - only about £30. The stat I have is from a 4 litre diesel left hand drive, it took an age to come as it was Special order from Germany. It took so long to arrive I got fed up and ordered the lower temp kit. Asking £50 for it plus delivery - cost me £85, spanking new never been fitted.

[quote="Ubatoid"]
[quote="X5Sport"]
  Pretty rare for a stat to jam shut. 
[/quote]

I had two in as many months on my 4.4.
[/quote]

Yipe!  Won't be asking you for lottery numbers with that luck!  We're they OEM?

Think I agree with above. You looking for something that s just not there. If the guage stays in the centre.its fine. Theey are buffered to stay in the middle imsteadnof going up and dow  and worrying peoeple

Well I went ahead and fitted the 88 degree stat, and two weeks on its a much more pleasant beastie.

No hot smell, no constant worry about the impact of that heat and pressure on the cooling system.

No idea why BMW decided it should run at 110, but I've certainly not seen any downsides to running it at the lower temp. Which incidentally seems to be about 95, not the 88 stamped on the unit.


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