Originally Posted by dubgtr
This thermostat confusion is bothering me.
If you run a lower temp thermostat, the engine will run colder, end of convo.
Sorry to burst your confidence bubble but you're understanding of the thermostat is wrong.
A lower temp thermostat simply opens faster. It does absolutely nothing for an overheating engine. If your engine is overheating the only thing you will accomplish by running a lower temp thermostat is make the engine overheat faster. You have to diagnose the issue first. What is causing the overheat in the first place. Yes a faulty thermostat can be a culprit but so can about 5 other things I can think of off the top of my head.
Both the I4 and V6 thermostat begins to open at 176F-183F and becomes fully open at 203F. By running a lower temp thermostat (170F for example), the engine will warm up faster and in the event of an overheating issue will simply overheat faster.
Conversely, if you run a hotter thermostat you should have more time before overheating as the engine will take longer to warm up but at the risk (depending on the rated temp opening) of damaging components from excessive heat once it enters closed loop operation.
All of this comes down to one thing. If you are overheating then figure out why! Get a proper diagnosis. Trying to bypass the issue with an out-of-spec thermostat is only going to make matters worse and exponentially increase the likelihood that your car will end up in a junkyard. If you need help trying to self-diagnose an overheating issue then please by all means make a topic on the subject. There are plenty of people willing to take a stab in the dark at it but I urge anyone with an overheating issue to seek a professional diagnosis from a local shop. They have the tools, knowledge, and experience to turn a lengthy battle with an overheating car into a quick win. That's my opinion and will leave you with that.