I don't know if that would be it. The antifreeze has been changed out twice, both time when the water pump was replaced. I will check into that . A friend of mine thought maybe the turbo might be going bad. I don't know how to check that. The engine runs fine , gets good fuel milage, both towing and normal daily driving. How would the turbo be checked?

it's ok to butt heads, just don't do it with a butthead