Nissan Repair: 1993 Nissan Sentra Overheating, nissan sentra, heater cores

Question
I have a 1993 1.6 liter Nissan Sentra XE.  Two years ago I replaced the water pump.  Now I've noticed a temperature problem only when I travel distances on the freeway, not during short trips.  When I come to a stop after traveling for about twenty to thirty minutes, the engine temperature will rise almost to overheating.  When I resume driving, the temperture comes down until the next time I stop.  What could be wrong?

Answer
Tom,

Check your fans to make sure that they are working when you are off the road and driving slow or at a stop.

Change the radiator cap as the car is a 93 and you should change them out at about the five year mark.

Change the thermostat with a new one from Nissan.  Aftermarket units are not worth the trouble and it is worth the extra money to get the best.

I would to the things in the order above and you should be good to go.  Also, if it has been two years since the water pump it is time to change the antifreeze with Prestone and distilled water.  Do not back flush the engine as it will blow your heater core so do not force water through the system with the garden hose.  The heater cores are thin at best and 60 pounds of pressure is much more than the 13 to 16 pounds the system developes when under pressure normally.