overheating at higher speeds and heat blows cold

Sounds like you have air trapped in the cooling system. Hope that helps! Jim

That could possible be true. What happened i was driving from New Jersey to Maine and when got to New Hampshire the car started to overheat and dump antifreeze out the overflow. Then roadside assistance came and we filled up the antifreeze and then I drove it for about and hour and the level went down again so i filled it up and continued for another hour and a half at 70 miles an hour and when i park the water level was good and it didn't overheat. then today i drove back to New Jersey and for the first 5 hours I was driving at 65 to 70 with no problems but as soon as i went to 75 to 80 it the temp has risen so I back off. I'm not sure why the vehicle overheated what I did notice is that when it started to happen I had the A/C on and it was cold and then starting to get warm and then i smelled antifreeze as it was burning on the manifold so pulled over to see it overflowing. I will bleed the system tomorrow to see if that clears it up. Thanks a lot for your response.

You're welcome. Glad to help! Keep us posted! Jim

Thanks for your response. I did change out the thermostat, radiator, water pump, hoses and heater core. If the thermostat goes bad wouldn’t it constantly overheat to where it boils out the radiator cap? Last year the heater core was clogged so I just replaced everything since it wasn’t to expensive to change out just time consuming for the heater core. I’m going to bleed the system and see if that helps.