wtf is wrong with my temperature/ temp gauge? 1990 240sx ka24

[Black R]

the car overheated recently and ever since then, the temperature gauge is acting up.

the car takes forever to warm up and even when it does, the heater doesn't really blow very warm..... driving on the highway makes the temp go down VERY low.....

is it possible that i broke my thermostat somehow and it's just staying permanently open now? is this common when a 240 overheats?

[onosqv]

That's what it sounds like. you should pull the thermostat and check it for opening/closing.

- Drain coolant- Remove the lower radiator hose, thermostat housing, thermostat- make sure thermostat is in "closed state"- put thermostat into pot/pan of water, heat water up to around 180 F (I think it's suppose to open around 160-169 F). You should see it pop open.- Reinstall, bleed coolant, and check for other stuff.