back to my story of my d series....get the therm simplyfast reccomends or a new OEM FROM A HONDA DEALERSHIP,this is the only thing that fixed my prob and it was very similar to yours d series or not[and I do have a b16 now for whoever cares]I went through 3 therms that all opened right at or close to correct temp,the dealership one that was a little more fixed the prob right away,granted I still dont know what exactly caused it but ........