Low coolant temp

[asshanson]

Emily's 2001 zx2 just had the CEL go on the other day, and a couple days before I noticed coolant temp on the gauge would take forever to get up past cold, and barely even makes it to the normal "warm" point if you're idling in traffic. As soon as you hit the interstate it goes back down a little closer to cold.

I checked the obd2 logger and it said it couldn't warm up enough while in closed loop mode.

So I'm thinking either bad coolant temp sensor or stuck open thermostat. What do you guys think given the symptoms? Yes the car has enough coolant.

My first guess was coolant temp sensor, but do those start to go bad and just read low? Or do they go out completely and read way off?

[Super Bleeder!!]

thermostat

[Kracka]

thermostat
x2

[asshanson]

Replaced the thermostat, it seems to get/stay warm like normal now, but the CEL didn't go away. I'll have to reset it tomorrow and see if it comes back. The old one wasn't stuck open, maybe just a weak spring or something.

It was really weird, all plastic pieces. Three 10mm bolts to get the housing off the head, plus a couple spring clamps on hoses, but the thing that kept the thermostat in was three torx t25 that were really tough to get to. Plus there were no paper gaskets, all rubber orings that were reusable.

[Kracka]

Sounds like my POS Contour.