Re: 00 jeep grand cherokee?
I'd start by trying a radiator flush, it may need flushed out to get rid of any debris that may be causing your problem. And also check for any leaks, bad hoses, etc. I had the same issue with a prior vehicle and did the same things you've tried, flushing the radiator, new thermostat, new radiator cap, and new hoses solved my problem.
2001 Silverstone Metallic WJ Limited:
Gen III Clear/Chrome Projector/CCFL Halos/LEDs, 8K HIDs, 8K HID Projector/Halo fogs, Clear/Chrome Tail Lights and 3rd Brake Light with LEDS, Diamond Mesh Upper and Lower Fascia, Spectre CAI, Breather Filter, Cabin Air Filter, Low-Temp Thermostat, Jet Stage 1 Chip, MagnaFlow Exhaust with Resonator Tip, Shorty Antenna, Front/Back De-badged