Hello, As for the thermostat it is on the right side of the engine (facing firewall) on the passenger side. The temp sensor is on the housing. The thermostat being blocked is a good suspect. I would reccomend getting a FSM. www.courtesynissan.com an '89 Sentra does not have fan belts, it is front wheel drive. Other things to look at would be: Blocked radiator Air trapped in head Non functioning radiator fan(s) Failing water pump Faulty ratiator fan relay. I would sart by bleeding the cooling sytem, then checking for circulation. then drain the coolant system and replace the thermostat and run Prestone radiator flush. Then refill with a good fresh 60/40 water/coolant mix. If that does not solve your problems take it to a mechanic. I can't remeber if the Sentra radiators can be rodded out or not. Some can some can't. If you have any other info post it. It will help us help you. Good luck, Ben H. Baird '91 SE-R
