My '93 Nissan Altima is overheating and the heater has stopped working. These problems started at the same time. I replace the radiator about 8 months ago (it had cracked up by the filler neck) and replaced the thermostat about a week ago as it was taking a long time to build engine heat and the heater wasn't working well (warm air, not hot air). After I replaced the thermostat, the engine would build heat to the proper temp in 10 - 15 minutes. The temp gauge shows that it is warming up in the same time frame, but then in another 10 minutes (20 - 25 min. of engine running time) the temp gauge climbs and indicates the engine is overheating. Also, the heater fails to get hot. We moved from Florida to Colorado in August, and the temp issues started when it started getting cold (30 degrees F and below). My guess is that the waterpump has failed and is not circulating coolant, causing the engine to overheat, and since no coolant is circulating, the heater doesn't work.
Dec 7, 2009 at 1:50 PM