I posted this topic awhile back but im getting so much cold air to the car that it stays this way when I drive and at idle it goes back up. EDIT** does anyone have this same thing?

CHECK ENGINE LIGHT IS ON FOR REAR O2!!!!!!!! not sensor just a question for water temp sensor


I also filled the tank and at a half im at nearly 140 miles I couldnt believe it cant wait to finish the tank to see

 

Thermostat sticking open?


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Check engine light on!

 

It works just fine the water is just super cold but that could be just the weather im pretty sure when summer comes it wil be different

Its the rear o2 tephra rom will be installed soon

 

Texas? Well, it is Little America here and my temp is up and steady within a mile.

 

I would absolutely not drive the car with a Service Engine Light ON even if its driveable knowing that water temp is flucuating erratically. Do your self a favor and change that thermostat. Super cold water in a engine will not stay super cold for 5 mins, the ecu is telling you something and that something could perhaps be a thermostat issue.

 

Are you running an aftermarket rad.?

I had similiar issue to this but mine didn't come up when sitting still. Try taking the plug for the guage off of the thermostat housing and sand it down to make a clean connection. This might not be whats going on but it only takes a minute.

I don't imagine it's colder in TX than it gets here. What temps are you getting there?

 

Just make sure the thermostat is an original Mitsubishi thermostat for the EVO.

These threads come up every year.

 

I just said earlier its the o2 sensor thats not the thermos stat

 

It looks like one of the three:

Stuck open thermostat - replace
Bad sensor, and/or connection to gauge - replace/clean
Fan is constantly on due to bad relay or sensor - replace

That is what I would look for. Check your codes again, see if it comes up with a "Thermostat regulating temperature below operating thresh hold". That would rule out suggestions 2 & 3.

 

Okay, I'm confused, stating "water temp not broken" is like saying front tire not flat. Are you bragging or complaining?

 

No, a cooling system has measures to maintain operating temperature. Either it's one of the above suggestions, or you have some aftermarket thermostat.


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What is the temperature that an OEM thermostat opens?

 

176 F

A thermostat is operated by a wax pellet. The wax melts, the liquid wax has more volume than the solid and this moves a piston. In other words, this isn't a digital thermometer.

 

Yes, I know how it works but didn't know what temp the OEM works at. I am considering buying the Cosworth thermostat which opens around 159 degrees and I was trying to xompare.
Thanks