Hello,
I'm new to this forum and I'm looking for some help. My 04 Trailblazer started overheating and/or running at hotter temperatures in the hot summer days. I have not had any issues in cooler temperatures. I have replaced the thermostat, water pump, radiator, fan clutch, upper and lower radiator hoses, temperature sensor and belt tensioner. The problem only happens in hot days when the AC is on and whenever we go up a long hill up the mountains. The problem goes away as soon as I turn the AC off. Any help will be much appreciated.

Thank you.

 

I'd put a temp gauge in the radiator, to make sure it was at 195 F. When you turn the A/C on, the condenser is going to pass more heat to your cooling system. What kind of radiator did you install?

 

Everything I installed is ACDelco, except for the water pump.

thank you.

 

Doubtful its a water pump issue. Back in the day, we used to use two core radiators, not one. Have you bled all the air out of the cooling system yet?

 

Henry thank you for taking the time to help. I truly appreciate. I took off the radiator cap and let the car run for a while. Is there a better way to get rid off the bubbles?

thank you.

 

Thats one way and the easiest to do. If there is any coolant plug or hose higher up on the engine, thats a better way, but dont get burned.

And run the heater on full-blast, hot. That's the best way to get all of the air out of the cooling system in my experiences. There is also a cheap coolant additive that
will make a motor run a bit cooler, called Water Wetter:


Most auto stores have this brand or one just like it, not just Amazon.

 

Thank you. I will try that.

 

Did you check the coolant mixture level ? Should be a 50/50 mix or there about. Do not want to run straight coolant .

 

Hello,
I did 50/50 with distilled water. I burped the system yesterday and nothing changed.

thank you.

 

Is your A/C condenser, mounted in front of the radiator, clear of anything like bugs, dirt and so on? There is nothing blocking the front grill?