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1999 BMW 328i Question: Thermostat Open and Check Engine Light Is on – What Are Potential Issues?

 

Question

smbmw7, Santa Monica, CA, September 06, 2010, 18:54
 Rookie

My 99 328i has a check engine light on. I scanned the Car with a scanner that can scan for BMW propriety codes and it says the my thermostat is open. What are the potential issues if I keep driving the car with the check engine light?

Thanks,

2 Answers
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  • Medium-star Best Answer
    Bret Bodas from RepairPal Test Shop, September 06, 2010, 22:03
     Master

    Your engine will not reach operating temperature, causing it to be produce more emissions and be less fuel efficient. You have poor heater performance as well.

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    smbmw7, September 10, 2010, 16:30
     Rookie

    Thanks for your response! Based on your feedback, I had the thermostat replaced and all is working well.

    Cheers :)

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  • Answer #2

    danielsreseda from Daniel's Automotive, September 10, 2010, 10:08
    Profile_thumbnail
     Technician

    HOOK UP A SCANNER AND WATCH OPERATING TEMP
    IF THE ENGINE IS COLD ALL THE TIME, THEN THE CAR WILL RUN RICH, USING
    EXTRA FUEL PLUS DAMAGING RICH CONDITION.IN AN EXTREME CASE , THERE IS AN INTERNAL FIGHT BETWEEN COLD AND HOT PISTONS BECAUSE OF THE VARIANCE IN COOLANT TEMP.ALSO OBSERVE LONG TERM FUEL TRIM.REPORT BACK WITH FINDINGS.

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    smbmw7, September 10, 2010, 16:29
     Rookie

    Thanks Gentlemen for your responses! Based on Bretb's feedback, I had the thermostat replaced and all is working well.

    Cheers :)

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