I've been trying to drive the car around in the Texas heat, but my car loves to slowly creep up to the high 220's when I'm on the highway with the AC on. The car has the air dam installed, it has the 4th gen radiator and fan setup. I've tried running the car with and without a thermostat, but the outcome is still the same. I've even tried running a 3-row radiator and a dual SPAL fan setup, but this car will still get up there in temperature. I've tried jacking up the car from the front to try to bleed all the air from the cooling system. The engine is a rebuild short block, so it has all new head gaskets, and the heads were resurfaced.

When I'm cruising on the street, the temperature doesn't seem to rise as fast as it does driving on the highway. I am missing the plastic piece that goes around the hood latch, so I suspect that maybe this is allowing air to go up and over the radiator? But any recommendations are welcome, as I can't think of anything else that can resolve this issue.

 

This may sound silly but similar issue im having. my trans am is an 84 that was factory carb with a mechanical fan. I now have an ls but ive noticed that the air dam on the facotry carb cars is smaller in height than the later cars that had the E-fans. I may try to switch to the later style.

 

That's a bit odd. I actually have an 84 factory carb car, and my car came with an electric fan on it. My air dam is maybe about 5-6 inches in length.

 

Where are your steam vents hooked up to?

 

It's a four corner steam kit, and it goes to the upper radiator hose.

 

What is your heater hose setup? You can't cap-off the heater hose outlets on an LS engine and expect normal running temperatures. The LS water pump plumbing needs constant coolant flow through the heater core (or some kind of bypass), because that's how the thermostat gets hot water.

 

I have the heater outlets looped together, I made sure to not just cap them off.