2003 BMW Z4 coolant light coming on after replacing thermos

2003 BMW Z4
54,000 MILES • 6 CYL • 2WD • AUTOMATIC
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BRIANZ4
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  • 1 POST
After we replaced the thermostat on my 3.0i Z4 the coolant sensor light will come on intermittently usually on the freeway. The light will go off after getting off the freeway and the temp gauge never indicates anything other than normal. The coolant level is full but the light continues to come on.
Nov 30, 2009 at 8:54 AM
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RASMATAZ
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  • 75,988 POSTS
Hi BrianZ4 and TY for the donation Check and test the coolant level sensor, also be advised you have a coolant temperature sensor for the computer and an engine temperature gauge switch for the engine


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Service and Repair Notes Replacing Level Switch For Coolant Loosen screws (1). Raise expansion tank (2) slightly. Installation: Insert locating pin (1) into locating bore (2). Disconnect plug connection (1). Turn coolant level switch (2) approx. 90 °in direction of arrow and pull out.
Nov 30, 2009 at 9:34 AM
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DOCHAGERTY
  • ✓Experienced Mechanic
  • 9,606 POSTS
It is possible the expansion tank is the culprit and will require replacement. The float that commands the light on is possibly faulty, and/or the reed switch.
Dec 6, 2009 at 11:14 AM
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