What is wrong with my ac

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. It sounds like you're speaking of air conditioning, not coolant. Although, truly I cannot be sure. Thermostat replacement does not generally affect or correlate to air conditioning performance. For air conditioning related concerns, you must see a technician near you who is trained and legally certified to handle refrigerants. Refrigerants are toxic gases that can negatively affect the environment, so it is super important that you defer to folks who have these certifications and skills. Reach out to a shop near you - https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.