Every Nissan I've owned has needed a thermostat changed except my '86 Stanza wagon. Most fail in the open mode, the engine never warms up. I had the second one in the '97 Maxima stick closed. I'm waiting for the '05 Max to need one.

 

lol, so I take it this is a common issue huh. fml

 

FYI, my problem ended up being the radiator cap. Mechanic did a full cooling system pressure test and everything was fine. Repalced thermostat for good measure.

 

It's not. Nor is a bad water pump. If there is a problem with the water pump, it's the o-ring that start leaking. It doesn't cause cooling issues though.