My 95 maxima generate hot air fine on the streets but it become warm on the highway. The temp gauge also goes down on the highway and come back up when driving on the streets. What could be wrong?

 

It could be a bad thermostat. I don't know about Nissan, but most manufacturers now install fail-open thermostats.

 

[QUOTE]Originally posted by sinewave
It could be a bad thermostat. I don't know about Nissan, but most manufacturers now install fail-open thermostats. [/QUOTE

What does fail-open mean?

 

When a cheap thermostat fails it usually fails in the closed position, causing your engine to overheat because of lack of coolant flow. I suspect that too many people were getting replacement engines under warranty because of the failure of a $5 part. About 10-15 years ago, someone developed a fail-safe or fail-open thermostat. This keeps your engine from frying, but also cannot regulate flow to warm up the engine.

The most common symptoms of a bad fail-safe thermostat are poor gas mileage, low reading on the temp. gauge and poor cabin heating.