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Discussion Starter #1
I have a 2012 X5 35i and 43,000 miles. About a week ago, anytime when I turn on the A/C on over 65f and also turn on the blower, the engine cooling fan runs high speed every 4 to 5 seconds. When I turn off the A/C and blower, the cooling fan stops. Everything runs fine if I set the A/C temperature is below 65f.

I tried to turn on the blower on without the A/C on and the cooling fan stills run high speed every 4 to 5 seconds. I tried the heater too. I get the same results. Is it caused by water pump and thermostat or any temperature censor? Anyone have the same problem?
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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Everything runs fine with "the AC temperature set below 65f" or above?

Your description sounds like the MAX AC function description.
 

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Discussion Starter #3
It only occurs above 65f.


Looks like the temperature censor isn't working right. Even with the A/C off and the blower on, this happens. I tried water pump test without engine on. The Cooling fan starts to run with high speed. The test was done after engine was shut off after five hours.
 

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Discussion Starter #6
I took it to the dealer today and they replaced water pump and thermostat for no cost. Everything runs smoothly now. Maybe I was lucky to have the dealer that helped me out. This was at the BMW dealership in Turnersville, N.J.
 

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There is a (not so) secret warranty on the water pump even if you are out of warranty. Especially it if just recently expired. Dealer has the authority to get it covered.
 

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So question for diesel owners: when would you change good ole mechanical water pump on 35D in order to prevent problems?
 

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So question for diesel owners: when would you change good ole mechanical water pump on 35D in order to prevent problems?
when it fails?

:angel:
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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when it fails?
Is there a reliable sign of impending failure?

I read about BMW's evolution of bearing/seal leak-off design that kind'a eliminates leak-off as an indicator of failure. Preemptive replacement must balance the possibility of consequent damages (intentional or not).

If it ain't broke, don't fix it, lest one fix until broke - real soon with a BMW.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
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A VW TDI water pump should be done with the timing belt as the access is the same.
 

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DO you know what is scheduled mileage for water pump replacement? VW is 120K, not sure BMW.
Havent seen it published.

Like transmission fluid for a few years with them....

Acuras we used to do it with the timing belt at 105k
 

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Havent seen it published.

Like transmission fluid for a few years with them....

Acuras we used to do it with the timing belt at 105k
Yeah, I am thinking probably 90-100K is safe bet just to be on a safe side. That is what I did with all cars, always cut schedule on timing belt and water pump by 1/4.
 

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A VW TDI water pump should be done with the timing belt as the access is the same.
OP has a 35i (gas/petrol) engine, I presume it has a timing belt (not chain) and requires a maintenance replacement around 80-110K miles . . .

For those of us with a 35d diesel, it has a timing chain (P/N 13528506969) . . . which I am told lasts "for life" . . . always a dubious claim!

Any idea when (or if) a timing chain should get replaced - beyond 200,000 miles?

My guess/concern - when the timing chain has worn down sufficiently it can/may jump a cog or two and the result is the same as the timing belt breaking . . .
 

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OP has a 35i (gas/petrol) engine, I presume it has a timing belt (not chain) and requires a maintenance replacement around 80-110K miles . . .

For those of us with a 35d diesel, it has a timing chain (P/N 13528506969) . . . which I am told lasts "for life" . . . always a dubious claim!

Any idea when (or if) a timing chain should get replaced - beyond 200,000 miles?

My guess/concern - when the timing chain has worn down sufficiently it can/may jump a cog or two and the result is the same as the timing belt breaking . . .
All BMW's have timing chain except some 4cyl engines from beginning of 1990's.
 

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150k miles the the maximum service lifetime that a water pump can go saftey with proper coolant change intervals i.e. 50k miles. I plan to knock my out at 100k along with my long list of major service.

All BMW's have timing chain except some 4cyl engines from beginning of 1990's.
The m21 diesel and m20 gas are the only US BMW lineup that had timing belt.
 
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