2019 trax overheating

[Daveone23]

I replaced the thermostat, radiator
Cap and its blowing the radiator
Cap. Water pump is not leaking.
Head gasket test looks ok. Fan is
Working. What
Could be causing this.

[maxwedge]

Welcome to AF. Ok, how do you know the hd gasket is ok? Start the engine from cold, wait one minute and see if the radiator hoses are pressurized.

[Daveone23]

I used th CO gas tester. Its very sensitive.

[maxwedge]

Ok, I've used that test also, but not every head gasket issue involves combustion gasses. Plugs show any sign of coolant contamination? As I suggested, does the radiator hose get pressurized right after a cold start?

[Daveone23]

Harder then when cold but not hard. Even when super hot hoses are not hard. I pressurized the system to 20psi and it holds.

[maxwedge]

Using an infrared thermometer, check the temp differences between the radiator hoses, an efficient radiator should have at least 20 degees difference. Also look for cool areas in the core. Of course make sure all the air is bled out of the system.

[Daveone23]

This car has no bleed screw. I ran it for a while with
The overflow cap off hoping it would bleed off.