Usually only when a problem occurs. But they do last a bit longer it the coolant is kept up with as it is what lubricated them.

Most thermostats I change at work are due to a fault stored in the DME for map cooling, thermostat stuck open. As the BMW thermostats are normal in thermostatic opening, but also have a sealed body of wax built into them that is heated by the DME for additional control of amount open/closed.

As for the water pump, they usually get changed at high mileages due to either seeping water from the weep hole or excessive bearing slack/bearing failure as what happened to our friend M3dom here.

Maybe threads like this one should be a reminder to us that we may be due for a proper coolant flush job, and YES the BMW coolant is better than any other coolant I've come across. Partially because of the metals used in BMW engines, the coolant has to protect against electrolysis in aluminum, steel and magnesium, not just rust.

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"When you do things right, people won't be sure you've done anything at all" (Bender, futurama)

You make something idiotproof, they'll make a better idiot

You think professional is expensive, just wait until you pay for amateur.

Never let your sense of morals prevent you from doing what is right.

Examine what is said, not who speaks.

X5 pics

RIP 4.6is.....

2003 4.6is