Water pump failed at 63k miles, why was there not a warning light?

[Maurtis]

We have a 2008 135i, it is my son's car. On his way to school it threw a temp error symbol dash and went into limp mode so he pulled over and called home. I drove up to meet him and we switched cars so he could continue on to school.

I plugged in my generic OBD dongle and started the car. I saw the temps climbing at idle but there were no codes or warning lights on the dash.

I shut the car down and called our mechanic. They came out with their tablet and the diagnostics said the water pump failed. I know this is a common failure, but if the computer knew the water pump failed why not put that on the dash? Seems like something the driver should be aware of? Why wait until the temps are dangerously high to warn the driver when the underlying cause is already known?

[clavols]

I've had a similar but opposite experience with a 2013 135i (N55). The warning light for overtemp came on but then went off while waiting at a traffic light. It came back on and then went into overheat and limp mode within a mile, but the on-dash temp gauge was still showing normal??? I opened the hood and the engine didn't seem any hotter than normal and checked the coolant which was ok - is there a chance this is a bad sensor of some kind?

[GoRomeo]

Dont forget to Change your thermostat too.

[1and1]

Originally Posted by clavols

...but the on-dash temp gauge...

clavols, that's an oil temp gauge, not a coolant temp gauge.

[Lester]

You should also hear the electric radiator fan going full blast.

[Maurtis]

Originally Posted by GoRomeo

Dont forget to Change your thermostat too.

Thanks, the mechanic already included the thermostat on the estimate without me even having to ask