Thermostat stuck open?

[ohno06gt]

I went to burp my coolant today and the car never went over 187 degrees. It idled for about 35 minutes and would hit 187 for a bit then drop back to 185. It was pretty cold outside, around 32 degrees. I'm thinking maybe the thermostat was stuck open and it was steadily flowing? I didn't hear any air bubbles in the cabin and the heat inside the car was working great. I revved the engine a bit, squeezed the radiator hoses, a few bubbles here and there but less than I was expecting.

 

I've heard some thermostats stick open when they fail but not sure if that is what's going on. Any ideas?

[Infosecdad]

OEM or aftermarket thermostat?

 

Sounds like it might be a 185 degree thermostat.

[whitexc]

^^^ or even a 190. Depending on the brand and age....you may have been at that point.

 

Sent from my SM-G996U using Tapatalk

[MoleMan]

@Infosecdad,

 

Good call out on that. I have had so many issues with aftermarket thermostats in the recent five years on various cars that it’s to the point I just buy factory ones from the dealer. It’s funny you go in thinking you are going to get ripped off but they are only a few dollars on average more then an aftermarket part.

 

@ohno06gt does the car throw any codes? I nursed a bad thermostat on my daily Civic for six months and what it would do is throw a code every 1500 miles or so and then once reset the code went away for another 1500 miles or so. It was doing what you described and just was stuck open but the car drove fine on the highway and the temp was fine. I know on my sixth gen when I drive it I put the setting on the car info screen where it shows the coolant temp and it’s always running somewhere in the 199 to 201 range.

[ohno06gt]

Yea no codes so far, it's an OEM thermostat. After driving it seems to be opening and closing normally just a little cooler than I expected.