Help: procedure to check coolant system
 

The electric coolant pump died on me a week ago, and my Indy service shop replaced it along with the thermostat. Long story short, the new pump didn't work so got a replacement from BMW. However shortly after we found out the new thermostat was also defective and engine was overheating. My mechanic told me something like this never happened before.

Now, I'm totally paranoid about this and would like to check if the cooling system is working as expected at least daily. I plan to obtain cheapo Bluetooth OBD2 module to get live data readouts including coolant temperature. Until then, what are the best methods available? any suggestion is very much appreciated.

Also, I noticed the radiator fan starts immediately after starting the engine. My 2011 328 doesn't do this. Not sure if this is expected - I thought it is computer controlled and fan does not start until engine temperature reaches certain point. This was done early morning, so engine was cooled overnight.

I found the "Hidden menu" procedure to bring out the real time coolant temperature reading on the gauge cluster which is really cool and useful.

The temperature stays between 95C to 105C, at city driving speeds with AC on.

In comparison, my 2011 328i hardly reaches above 100C, almost rock steady at 99C.

Looks like all is well but should I be concerned about the coolant temperature being 3-4C higher on X5?

What is the hidden menu - how do you get to it?

Here's the link. Works on both E70 and E90. Should work on many others too.

Remember to add up last 5 digits of VIN, not all digits, for the unlock code.

http://www.scoopz.com/m5board/E60_Hi...structions.pdf

iirc, The electric fan will also come on anytime the AC compressor is engaged and calling for cooling.... even if the engine is cold.

On other cars I've just verified by turning the AC off when cold to see if the secondary electric fan stopped.

The chance of both those parts being defective is very slim. You may want to have another shop take a look.

Thanks. I'll try this out next time.

I was about to take the car to BWM service, and I will if the cooling system still has issues. Even one part being defective was already slim, the mechanic said. Poor guy had to perform the same job 3 times, and the third time was done outside of his working hour.

I don't think they are lying, but it's hard to believe both parts are defective.

BMW has a odd note on the install of that pump, it says "Installation note:
If the electrical water pump is used again, it must be turned by one rotation due to the
breakaway torque at the blade wheels." This might have been what made them think the thermostat was not working. Hard to say, I would not have thought to rotate the pump after installing if I had not seen this.

Well, not sure what it is meant by "pump is used again" - sounds to me if the pump was taken off and reinstalled? Probably doesn't apply to new pumps?

Anyway, some update. I *think* the cooling system is working based on the coolant temperature reading but I need to verify few things.

* Is it normal to have the radiator fan start running when engine is started at cold? I was told that this normally only occurs if engine is hot or AC is on.
* My car's keep saying coolant level is low, although the coolant level is fine. The mechanic told me the sensor might be broken. Does the coolant sensor break like this easily? It was fine before the waterpump broke down.
* How long does it normally take for the coolant temperature to reach 100C? With outside temperature of 25C, it took almost 10min to reach 100C, from 35C. I'll have to compare this against my other car but does this sound normal? My concern is if the thermostat is stuck open now, instead of being regulated under computer control.