Any thoughts as to why we would need to fill the reservoir every two weeks or so? Back story. Son took in to have thermostat replaced and general "check up". Shortly afterwards his engine was getting "hot". When he checked the cap was off the radiator (he had no clue what happened to cap - thought it maybe broke and fell off - 20 yr. old). He had to special order a cap from Jeep so it took a few. Vehicle kept getting "hot" and he kept refilling. We have since realized that the cap was left off when the thermostat was replaced. Unfortunately they wouldn't do anything about it because we didn't realize this until the repair warranty had expired. Thinking this has something to do with it needing constant refill. Never any fluid underneath. Before taking to shop just wanted some thoughts. Wishing it would be a recall issue like the engine fan and oil usage issue but haven't seen anything like that. TIA!