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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4965
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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2001 S 500 ..filled with gas ..16 gals. within 7 miles the

Customer Question

2001 S 500 ..filled with gas ..16 gals. within 7 miles the check coolant light message showed on the display. by the time i got home engine was idling rough but the temp gauge was normal. Notice water vapor dripping out of tail pipes. Could this be bad gas?
Submitted: 1 year ago.
Category: Mercedes
Expert:  Lou P. master tech replied 1 year ago.

Hello Bill, there are 2 reasons that you will see that "check coolant" message,

  1. the coolant is actually low or the sensor in the reservoir is bad
  2. the radiator fan has failed and the engine control unit does not recognize that it is plugged in.

this will just be a coincidence with the fuel fill, and water out of the tailpipe is actually a sign of complete combustion. so i would not be concerned with the tailpipe. i would get the car checked out so there are no overheating issues. i hope this helps, let me know if you need more info, i am unsure if you are the type to fix yourself or have a shop do the work. Please take a second and click the stars at the top of the screen to rate me so i may receive my credit , 5 stars is ideal , please request me in the future.
Keep in mind then when you rate it does not end our conversation. you can still return here to me for follow up information if needed, Lou P.