1999 2.0L SOHC auto 145K miles

Please give final thoughts, I'm going to start replacing things Saturday...

1. Has MLS head gasket
2. Car overheats after driving 10-20 miles.
3. Idles fine for 2 hours, no problem
4. drives ok for 30-40 miles on flatland, 5-10 going uphill (I drive 4000 verticle feet home every) day. Will overheat in 1 mile if a steep hill.
5. Water Botlle will not suck fluid
6. System seems to keep pressure.
7. Radiator cap is tight.
8. Heater does NOT work

I'm thinking water pump....

 

Bad thermostat or bad radiator. Have you checked the flow of coolant? Do you have the proper 50/50 mix of coolant and DI water in it? You say the radiator cap is tight, but is it good?

 

Just because the radiator cap fits tight dosen't mean it's good. When the coolant dosen't return it's a failde cap. The other possiblity is the return hose is cracked ot the overflow bottle cracked. When was the last time the water pump was replaced? Was it a premuim brand? I use Cardone Select new pumps. As a last resort have the radiator flow checked at a shop.