Here's some info on the cooling system;











So the stock thermostat cycles at 176 to 183 degrees F, which tells me that would be the "Normal" operating temp when the needle is sitting at that second hash mark. It would no doubt show a slightly higher temperature (190-200 or so) due to the proximity of the temperature sensor in relation to the thermostat, so it really shouldn't be of any concern until the needle gets up near the Red area at the top of the gauge, which at that point you're approaching probably 225 or higher. I'd shut it down before it gets into the red area of the arc, or as soon as you can safely do so.

Did you notice the temperature gauge needle moving toward the top of the arc when it started making noise? How about the Red Triangle flashing in the center of the gauge cluster?

Glad that it seems to be ok at this point... What a relief!

 

Yeah, you're probably ok. Did the temp gauge reach all the way up to the red mark? I know you said it was knocking, but did the gauge actually show it was overheating before you shut it down?

My car with 217K miles overheated recently when the upper hose busted, but it did not get up that high when I noticed it. It has been driving fine for a few weeks now.

 

Thanks for the info @2KHarrier !

That's the thing, I didn't really pay attention to the coolant temp gauge when this was all happening. I don't think it went up but I could be wrong. The knocking didn't make me think it was related to overheating so maybe that's why I didn't look? Or I was freaking out. Maybe the temp sensor is bad? But the fact that the dealer said it went to 270F and the coolant overflow tank melted is what worried me. I should have asked for the melted overflow reservoir.

@Longmire That's the thing, I didn't really pay attention to the coolant temp gauge when this was all happening. I don't think it went up but I could be wrong. The knocking didn't make me think it was related to overheating so maybe that's why I didn't look? Or I was freaking out. Maybe the temp sensor is bad? But the fact that the dealer said it went to 270F and the coolant overflow tank melted is what worried me. I should have asked for the melted overflow reservoir.

 

Drove the car today for 15 miles city driving. Coolant temp never exceeded 195F per OBD2 real time data...

Does freeze frame data reset after every startup?

 

Well, an ODO reading of 77777 should be pretty lucky.

 

@bbtri,

Sorry that’s not my picture. That’s a picture I found on the forums when I was researching what the coolant temp gauge should normally be at.

 

Not sure about freeze frame but my reader will say if a code is present (shadow) and if the fault is present on the current ignition cycle. I don't like to erase codes because I feel it's like historical data that matters, but I erased my wife's ABS fault since I replaced a part yesterday...

 

Mine!!! lol

 

270F isn't hot enough to seriously damage the motor, especially if you didn't drive it like that for ages.
Much over that or if you drove for some distance at that high a temp and you'd either blow the head gasket or else total the motor.

She normally runs up to 220F (start of the red section) but should stay stable as a rock in the middle of the gauge if operating normally.
Failed thermostats can often cause this kind of fault as they don't open and thus restrict coolant flow = overheat.
If she didn't blow steam out of the coolant bottle cap then you should be good to go.

 

@BigBoomer wow thank you so much for your response and reassurance. This makes me feel so much better.

Yeah, didn’t blow any steam at all. Just melted the coolant reservoir per the dealer.

I just thought 270F was high because the thermostat opens at 183F per @2KHarrier post. Also, the coolant temp didn’t reach 200F in my recent 15 mile city driving.