Overheating...it's not water pump, thermostat, radiator or fans - SOLVED

[zrickety]

Long story short, I was at autox a couple weeks ago and the car overheated at the end of the run. I have replaced the water pump, thermostat, radiator, and both fans are working. The car still runs good...when it's cold. I'm not getting any mixing of oil/coolant but it wants to sit at 237 degrees. At this point the oil pressure drops off and I get a warning. I've seen this happen on other makes with a cracked cylinder wall.
Has this happened to anyone else and what did you find? I'm going to tear the engine down this week and do some CSI.

 

[GIACUser]

Could it be you need to adjust your water/coolant ratio for these events and go for almost all water and water wetter? Just throwing it out there.

 

[zrickety]

Could it be you need to adjust your water/coolant ratio for these events and go for almost all water and water wetter? Just throwing it out there.

I wish. I tried letting it cool off and it heated up really fast. In the driveway it will sit just below the red zone at idle.

 

[king1138]

I wonder if you have an air pocket in the coolant? I've seen a few vehicles run super hot after significant coolant work caused by this. Do you have access to a vacuum bleeder?

 

[zrickety]

I thought that at first, but this issue started before I took anything apart and it seems to circulate. I am going to pressure test it.

 

[zrickety]

To resolve this post, it was a seized balance shaft...main timing chain was still running the motor but the water pump was not turning.
Car is fixed. Details in my timing failure thread.