2003 BMW Z4 coolant light coming on after replacing thermos

Tiny
BRIANZ4
  • MEMBER
  • 2003 BMW Z4
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 54,000 MILES
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.
Monday, November 30th, 2009 AT 4:54 PM

2 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 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


https://www.2carpros.com/forum/automotive_pictures/12900_cls3_1.jpg



https://www.2carpros.com/forum/automotive_pictures/12900_cls4_1.jpg



https://www.2carpros.com/forum/automotive_pictures/12900_cls5_1.jpg



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.
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Monday, November 30th, 2009 AT 5:34 PM
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,603 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.
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Sunday, December 6th, 2009 AT 7:14 PM

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