2015 Frontier Pro-4X: Blowing Cool Air While Driving

SnyperX

New member
Greetings from Wisconsin. I hate that my first post here is about an issue with my new to me truck. So have had my 2015 PRO4X for just over two weeks now. Love the truck, but have had a few issues with it already (leaking rear diff and sonar sensor beep after getting wet). Current issue is on the way to work this morning the truck stopped blowing warm air from the vents. I turned the heat off and drove a few miles. Turned the heat back on and it was warm again. Is this the air in the system issue that is fixed by slightly filling the coolant reservoir a bit past the max level?
 

Airmapper

Inactive Member
Most likely, very common issue on Frontiers and Xterra's. It will blow cold at idle but be back to normal under any raised engine RPM.

Get a jug of fluid from your local Nissan place and overfill it a bit, if that's your issue problem solved, if not you didn't hurt anything. Just make sure you get the right kind of pre-mix, I think it's blue.
 

SnyperX

New member
I'll grab a jug of the Honda/Nissan Prestone stuff. My dealer wants like $40 for the Nissan branded stuff. I am aware of the blowing cold at idle, but my concern was that it was blowing hot air on the way to work, started blowing cold, shut off heat, drove a few miles, turned heat back on, was blowing warm again.
 

bushnut

Adventurer
Could be an air bubble or a blockage, try flushing the system. Not that hard I did my 02 a few months ago after suffering a split heater hose.
I would look for any wet spots under the dash to rule out a failed heater core. Any smell of coolant?
Just today I fixed a leaking lower coolant hose by tightening the clamp. I noticed that there was coolant dripping onto the accessory belts and causing them to squeal on start up.
All machines need periodic maintenance.
Good luck.
 

Obrianmcc

Observer
Check the level in the actual radiator, not the expansion tank. My radiator was 1/2 gallon low and the expansion tank always registered as full.
 

SnyperX

New member
Expansion tank was all the way at minimum with cold engine. Added some antifreeze until a bit past the max line. Plan is to put it up on ramps tonight and run the engine with the overflow cap off to try and burp the system.
 

Obrianmcc

Observer
In both of my instances the expansion tank always read properly. At min when cold and max when hot. It took a couple hundred miles of driving each time before the level in the radiator dropped (or air moving forward). I recommend checking the actual radiator because there is a strong probability that since the expansion tank is otherwise functioning adding fluid to the expansion it my simply pump the extra fluid out vs drawing in back into the system. Once my level dropped I topped it off and it has remained full each time. I never experienced intermittent heat, but would hear a fluid sound emitting from the core area from inside the cab. That sound never reoccurred after the top off.
 

SnyperX

New member
UPDATE: With a cold engine running my expansion tank was at the minimum line. I topped off the expansion tank with the engine running (per folks over at clubfontier.org). I am going to continue to monitor. To answer an above poster I have no coolant odor or wet spots on the ground.
 
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SnyperX

New member
UPDATE 2: Well, things seem better. when I check the coolant level with a cold running engine and no heat the coolant level is well above the MAX line. With heat OFF and engine running the coolant is right at the MAX line. So coolant level seems stable now.
 

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