Nissan Repair: 2005 nissan frontier cooling system, nissan frontier, 2005 nissan frontier

Question
QUESTION: Hello Mr. Sudderth,

I recently had the cooling system flushed and filled in my 2005 Nissan frontier 4.0 v-6 at the local dealer.  The problem I am having is that the electric fan (passenger side of radiator) runs frequently, when it never did under normal conditions before I had the work done. The temperature gauge reads normal, but the electric fan runs quite often.  From what I have read, everything is pointing to air in the system and that it needs to be bled out to increase circulation of the coolant.  The dealer is telling me that everything is working as designed. Would air in the system and lack of coolant flow cause the electric fan to come on at any given time to assure sufficient cooling ?  Is the electric fans primary job to run only when the air conditioning compressor is on?  Is there a specific air bleeding process to be followed after a flush/fill job?  Any information you could give me would be a great help.
Thank you,

Brent Spies

ANSWER: Brent,

There is a process to bleed the air from the system using the bleeder screws at the top of the system.  That being said, I would think the air would have already migrated out of the system after several ignition cycles.  I would check the temperature of the system using a thermal gun to determine the actual temperature of the system.  The fan will run when the air is on and when the engine determines it needs augmented cooling.  Anything over 35 miles an hour is usually cooled by air running through the radiator.  So, if the outside temperature is getting higher than it was, over the winter, then the fan will kick on.  When the air is on both fans should come on, depending on the cooling need.

---------- FOLLOW-UP ----------

QUESTION: Mr. Sudderth,

Before I had the flush /fill job done on the vehicle, I never heard the electric fan running, as if the clutch fan provided adequate cooling along with good circulation of the coolant.  The outside temperature really didn't seem to affect it one way or the other. Could there be another cause of coolant not to be circulating in the system properly or erratically that would cause the electric fan to come on to provide the additional cooling needed to bring the engine to the specified temperature?  Even after driving at highway speeds the electric fan has been coming on within a minute or two once I get off the highway. Does this sound like it could be a circulation problem? Also I noticed the level of coolant in the overflow bottle doesn't seem to change whether it is hot or cold.

Thanks,

Brent Spies

Answer
Brent,

The thing that bothers me is the temperature is normal.  That leads me to think something else is going on.  If you get a factory service manual or a Haynes Manual you should be able to locate the bleeder screws.  They are high on the engine and again, I do not think this is the problem.  I would first check the fans, relays and the temperature that could be kicking the fans on.