I have the car for 6 years, last year my thermostat died and I changed it. After that something weird started happening. Even after a shorter highway drives (10-15 mins tops), when I turn the car off the fans start to work. Depending on the temp. outside they work for around 30 sec. but sometimes if I do city driving they stay on for 3-4 minutes. No error codes, coolant slightly above max, the temp stays steadily on 90" on dashboard. Not sure how normal this is? Thoughts? 
