Q: how do i know which thermostat to replace in 2013 chrysler 200

The only way to test a thermostat is off the vehicle by heating it to specified temperatures and then measuring the valve opening height to see if the height is within specification. If you are sure one of the thermostats is bad, replace both outright. Thermostats do not last forever and indeed they are replaced as a matter of course in any major engine work and particularly when the thermostat and water pump are accessed (or accessible) in timing belt replacements on many models. So, if you are sure one thermostat is bad, and your vehicle is equipped with two, replace both. OEM (dealer supplied) thermostats are recommended. If you desire replacement, please request service utilizing YourMechanic’s thermostat replacement service request page. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you get the best possible results.