Sorry for checking back late to all that have replied. I believe there is only one thermostat on this motor after all the researching I did, but I could be wrong. After I changed the thermostat that I know of I did my best to bleed air out of the lines. The only way we’ve done it growing up was parking on a hill with the motor up and do a cold start with the cap off of the reservoir until it stops producing bubbles, and stays at a constant level. I wasn’t able to finish bc when it got to operating temp it started to over flow into the reservoir again and I had to kill it. I feel goofy because I haven’t checked the hoses yet as suggested above