Mb 06 is 2 old, mb it wasnt bad enough, otherwise code shows

“The most noticeable issues occur when the thermostat gets stuck in either the open or closed position. a malfunction can result in a trouble code, generated by the engine's computer, which can turn on your check engine light. ”

“my 2010 Ody's engine light came on yesterday. Took it to my mechanic today and he said the computer code shows a bad thermostat.” 

That is why every time change water pump, recommended change related parts such as pullys, thermostat, belt, etc.
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Both leadships are very sharp.