[ZGadson]

I’m willing to bet my hypothesis is correct in that I spent 3 hours replacing my thermostat for nothing - hypotheses being that BMWs discriminate against non-OEM parts despite how insignificant the part may be.

Upon leaving the dealer after having suspension work done I noticed the engine light was on - it wasn’t when I dropped off the car . Went back in, argued (with zero result), and left having learned I now had a faulty thermostat. I found a thermostat on Amazon for around $50 so I figured it was worth a try since I’ve replaced a thermostat before and wouldn’t feel bad if $50 didn’t fix the problem.

Replaced the thermostat, bled the coolant system of air bubbles, checked for leaks, used BimmerLink to clear the error code, topped off the coolant, electrical connections secure, and even used a new metal hose connector in place of the stock plastic part known to fail, etc. Test drove and not even 10 minutes down the road the check engine light comes back on.

So my question is, is my non-OEM stat causing the engine light? Do I need to drive the car for a while so it resets on its own? Did I skip a step? It’s been at least 3 days and 100+ miles and the light hasn’t ceased. Fine with going to the dealer to have them replace it but this thing became an instant money pit the minute the warranty ended (shocking, I know) so I wanted to make sure I’m not missing anything first.

Edit: I also have a dash camera that ran the whole time so I watched all the clips and found no evidence that they caused the check engine light. Just an unfortunate coincidence.

[nobelium27]

You'll probably have best luck just reading the code with torque or have a shop read it out for you.

BTW, thermostat had a recall and should be replaced for free at the dealership. Not sure what'd they do about it now that you replaced it, but maybe you can put in the OEM back in and have the dealer fix it?