well this is just boggling me. Fans seem to be working, I can turn the AC on and the fans kick on, yet the temperature gauge will still go up until I start blowing hot air again...Sound like the thermostat? I NEED to fix this tomorrow so please help me out!

 

waterpump is known to fail. thermostat not likely. When was the last time the timing belt was changed?

 

Timing belt hasn't been changed yet, but i dont feel that is relevant to the problem. If it was the waterpump the car would not blow hot air, correct? It seems like an odd scenario. Fans seem to work, but they just don't come on when needed. The only way to keep the engine temperature down is to keep the heat coming out through the cabin, as soon as I do anything like switching the AC on, or just turning off the heat, the temperature gauge will rise. As soon as I turn the heat back on it'll go down. ::stumped::...

 

the timing belt runs the water pump. the oem pump has a plastic impellar on a metal shaft, the plastic degrades and either disentigrates or looses grip on the shaft giving intermittent or slow pumping. You're pushing it at over 100k on the original belt anyways, i would have changed it out at 60k if it was my car.

 

How long ago did you change that hose? I would think if it was immediatly before this happened you may have a shit load of air in the coolant system, try this, go out and remove your radiator cap and the start the car let it run at idle and see if a bubbles come out, Ive seen it some many times and people always think its something more serious, It could be it and its free and easy to check for, Let it run a good five minutes but if any is going to come out it will come out within the first few seconds