[7thondagen]

Hello,
Son came home and told me to come outside so he could show me that his car was smoking. It wasn't smoking luckily, but at this point I kinda wish it would've been. It was overheating-- steam billowing out of the engine compartment and temp gauge nearing the "H".

First thing I noticed is that the fans were not running. I went down that path-- replaced ECT, no dice. Removed the thermostat and boiled it and it appeared to not move whatsoever. Replaced thermostat along with the radiator fan switch sensor (the other thing screwed into the thermostat housing besides the ECT) and the radiator cap. Still gets way over the mid-temp it usually sits at. Still no fans. Both fans will come on when I push turn the AC button on. Fans will come on when I jumper the fan switch plug (the one that plugs into the sensor that I replaced on the front side of the thermostat housing). Bottom hose gets hot but not as hot as top hose. I tried to burp it but I need to buy the burp funnel to properly do so. I do detect a little bit of a boiling sound from inside the radiator.

Is there a particular voltage I can check for on the fan switch? Why would the car get so hot and still not kick on the fans? Am I barking up the wrong tree with the fans? I guess I can remove the new thermostat and check it again. I've seen no white smoke and engine oil doesn't seem milky. FWIW this is an aftermarket radiator, replaced a couple of years ago by me.

 

[7thondagen]

I have this issue

 

[7thondagen]

I have this issue

I’m having this exact same issue. Did you ever figure out a solution?

 

[Blues_hawk]

This is very likely one the common mishaps the d17 engine gifts people with at least once. There is a crush gasket on the EGR/Thermostat housing attached to the left side of the head. This chamber has a thin wall between water and exhaust and when it comes loose or leaks it will overpressur the cooling ssytem resulting in a full overflow tank, spots all over the top of the engine and hood and periodic overheating as exhaust gases are forced into the water jacket.
See my write up here for how this was discovered - with pics from the shop manual etc.: Hello Fellow 7th gen survivors!

I did the whole thing and it was a good time to do timing belt and water pump, but it was a pita and took a very long time, and others have verified that this egr/tc gasket is a good thing to try first as it can be done in a few hours w/o removing the legendary bedded crank bolt of shame. The torque specs I used worked fine and have lasted nearly 100k miles, but be aware of the aluminum threads rather than the bolt somebody mentioned.

Of course, the hg can be blown during overheating, and worse so ymmv. Good luck!