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Steve, BMW Expert
Category: BMW
Satisfied Customers: 25237
Experience:  BMW Expert
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Had x5 4.6 is 2 years ... I've had recent new exp tank all

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Had x5 4.6 is 2 years ...
I've had recent new exp tank all hoses to it (3) new cap... there are no leaks from it...
a new fan blade a new viscous coupling and fan cowling all installed correctly.
from cold engine is fine, when warm the coupling powers the cooling fan all the time from 1500 revs up its better over 3500 rpm but sounds like a jet engine... it can not be right it takes engine power down noticeably... the electric fan does not start... its been tested and has worked through the diagnostics unit the mech used, the heater gets warm... very hot actually... the temp gauge runs just over centre.. the oil temp gauge runs at just under half way around 95 degrees I would say.... I want. the car yto sound like a v8 not a jet..
does the electric fan come on if you turn the AC on?
Customer: replied 7 months ago.
I've not managed to get it too but the mech who hooked the car up said the electric fan was working as it should under the hook up diagnostics
Customer: replied 7 months ago.
don't mind a £20 fee but £35 is too much for an answer... just type to me
Customer: replied 7 months ago.
I bought a replacement elec fan and it was booked in for testing and possible fit... its not been fitted based on the the mechs test.. wanna buy one ?
Customer: replied 7 months ago.
that doesn't really affect the issue though..

Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you

I would suspect that the temp sensor that triggers the fan is faulty. I would have it replaced.

Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle...

Customer: replied 7 months ago.
I dont know the tech stuff to do with heater water routing , heater valve failure,what happens if thermostat is faulty... it doesn't overheat though

if the thermostat was bad the engine would over heat. the elec fan should come on if the engine is going slightly over center. Please do not forget to click a positive rating

Customer: replied 7 months ago.
that may disconnect the viscous fan ?
Customer: replied 7 months ago.
let it run less locked up ?

yes correct. Please do not forget to click a positive rating

Steve and other BMW Specialists are ready to help you
Customer: replied 7 months ago.
good reply will try that

you are welcome. please kindly click on a positive rating. you can post back at a later date after rating today if you would like.

Customer: replied 7 months ago.
the heater water is routed up to the matrix/controls in the drivers foot well the pipe gets very hot where it passes where your leg is and the cabin heats up due to it even in the uk. . so it is very hot...this means to me that the water is too hot ,I have bought a laser thermometer unit that gives all sorts of high temps depending where I point it ... thought it would make diagnosis easier but it hasn't just more complicated ... I will look at the sensor for the lecy fan that may make the car nice to drive did overheat once whilst in traffic prior to all the expansion tank replacements .. thank you
the fan is supposed to run when the engine gets hot so if the fan is tested good and it is not coming on, it does point to the sensor.
if the engine still gets too hot even with the electric fan, then the most common causes of overheating would be a failed waterpump or thermostat - or air in the cooling system.
Customer: replied 7 months ago.
great a couple other items to look at to then...water pump not been replaced but is not noisy at tick over