bmw X5 3.0 cooling problem

hello everyone!
i have a problem with my 01 X5 176K miles on it ...it overheats
i have the car for one year last summer had no problems
in winter when it got cold i realized that the car wont warm up enough and fast enough
so in January i replaced the thermostat(wahler) water pump( bosch oem) and all belts and pulleys
of course new bmw coolant and did the bleeding procedure for the air to escape
after 3 months,one day driving to work i saw the temp gauge going up really quick.. pulled over turned the car off opened the hood there was no smoke or steam but coolant everywhere it went off from the radiator cap
left the car in the hwy, later that day went to pick up the car and decided to add some water and start the car at least to see where the leak its coming from..
but there was no leaks and the car worked fine
next day went to the shop trying to find out the problem
but nothing was wrong with it
couple of days later it got cold so i had the heater on... and i realized that the day when the car overheated first time it was a nice day and after winter was the first time when i turned the heater off
so the car will work good only with heater on
if i turn the heater off and after of 20 min driving the gauge goes up really fast.. turn off the car for a minute start it again and good to go
3 days ago had the thermostat replaced again..(u never know..maybe was bad)
but the problem come up again
the reason why i replaced again the thermostat was cuz the lower hose was cold even when the car will overheat and sometimes will get hot too
please help if any ideas
SORRY FOR MY ENGLISH IF SOMETHING

Replace your expansion tank. And use a brand new cap. Do NOT buy a Uro brand tank, buy OEM.

Your car is not holding pressure for the cooling system. Running the heater acts like an additional radiator; as that's exactly what it is. Bad thermostat almost always throws a code.

thanks for a quick response!!
where its gonna be better to get this parts??
or maybe the brand that you can recommend... cuz i dont have a dealership around
only places will be napa or autozone
thinking to get it online can u suggest something?

Try Max at www.oembimmerparts.com , I buy most of my parts from them (no financial interest, just a customer).

http://www.oembimmerparts.com/catalo...86/6657024.htm
http://www.oembimmerparts.com/catalo...86/6657490.htm

If you have an automatic, you will probably break the auto transmission thermostat getting the expansion tank out (most everyone does). Might want to have one on hand just in case:

http://www.oembimmerparts.com/catalo...86/9046960.htm

If you want to confirm this is your problem, try a pressure test; I'd bet your cooling system will not hold pressure which is why it is overheating.
Also make certain your belts are routed properly; it's easy to mis-route them.

thanks a lot man!!!
i appreciated
took off the spark plugs today there is no sign of burning coolant
and tomorrow im going to the shop so they can do one more test to confirm that is nothing wrong
with head gasket and do the pressure test...
i actually got new cap,original but it was the same problem i guess need to wait for reservoir to come
ordered the parts so ill change them soon is possible hope i can fix it cuz its such of headache

Keep us updated.

hello everyone! please help!!
just replaced my expansion tank and cap...and cuz i had a small leak on the radiator it was replaced too
still have the problem
the auxiliary fan comes on.. doesant overheat that bad i guess cuz of new radiator the old one was original... but still
if i turn on the heater its working...with A/c on overheats...
the fan clutch works good..

Maybe the thermostat you replaced was bad but you're not seeing a code?

yea i did replaced second time...still had the same problem
im already thinking its a head gasket

I had same issues & took it to the shop & found out that my AC Fan was Blown out... Maybe that is the issue.

i already checked the fans... they actually come on when i drive in town...sometimes high speed sometimes low...so they are working really good

hey scott any other ideas what it can be?