Ok, I'll start from the beginning. I replaced my water pump a year ago. Then just before winter (this past October) I replaced the thermostat due to no heat. Car wasnt getting up to temp. When I replaced it the car did have heat but would start to overheat after driving about 15 miles. The heat starts to go away as the car starts to overheat. Then climbs fast. I do have a couple coolant leaks. One at the coolant resevoir and at the oil cooler. I dont have any oil in my coolant. Could the bad resevoir cause overheating due to lack of pressure in the coolant system? Also my lower radiator hose never gets hot. So this leads me to believe the system doesnt have enough pressure... Please, any advice is appreciated. THANK YOU!!!

 

Fix the coolant leaks , fill & bleed cooling system then see what happens.

 

yeah you can't bleed the system if there's leaks, and if there's air its not going to flow correctly. when i did my thermostat a few months ago i started it to make sure everything was on tight and the car got up to 235f, and then i bled it and it came back down to 198 or so.

 

Sounds like air in the system for sure. Air bubbles will get stuck behind the thermostat and trap it, keeping it from opening. That's why your lower hose isn't warm. Run it until it starts overheating (3/4 of the way up the gauge), then shut it down. Let it cool a bit and then carefully pop the cap to purge pressure (this is "burping" the system). Top off the reservoir and repeat. That should help get the air out and let the system work as designed.