I decided to replace the thermostat because I am having bad fuel mileage (17-18 mix 65% highway 35% city) and my engine temperature won't go over 80C and I read somewhere that a bad thermostat may be the cause.
(Before that I thought cooler engine temp is good for the engine).
The job is simple for DIY rookie like me, just remove 3 10mm screws (# 1,2,3 on the pic) on the housing cover using a rachet with a long extension. That should be done on a cold engine.
Unflug connector #4 else the cable will be in the way when removing the housing cover.
The cover and the old thermostat may sit tight perhaps because of the gasket sticking tightly, just use a little force. The spillage is minimal, about a cup of coolant.
Remove the thermostat and put the new one together with a new gasket in.
Attach the cover, start the engine and check for leak.
1: new thermostat
2: base of housing
3: housing cover, displaced
4: old (bad?) thermostat.
hoping for some mileage improvement.