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Heater blows cold air when idling - 2011 Nissan Pathfinder

Mine is exactly the same problem with my Nissan. I live in Montana and I can’t keep the car running while I wait for someone. Sitting at a light with cold air coming at me is really bad during winter.

Hi Alice, we can’t see the post you’re responding to. Is there a problem with your heat?

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yes, when idling the heater runs cold air. I live in Montana and can’t even keep the car running while waiting for someone. This has been a problem since I bought it.

Usually this is a problem with either the coolant level too low so check and add anti-freeze, or gulp. a head gasket leak. The head gasket can create an air bubble in the coolant to prevent the warm coolant from circulating until the engine speed is increased enough to overcome the bubble.

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Ironic. Motor is hot and so close to cabin but no heat in cabin. If air is cold at stop, turn off fan or keep switch on recirc mode. Then less outside cold air is sucked in. . You have verified inlet/ outlet hoses on heater core are both hot?

R51 generation Pathfinder coolant passages for the heater have very high point and do not bleed the trapped air easily.
Open the hood, check 2 fat aluminum pipes on the passenger side of the firewall - it is a small rubber cap there, secured with a clamp - it is special valve to bleed that air.
I do not recall exact sequence how to bleed the air, you can probably look it up on nissanhelp.com - this is where I found it when I needed it.

While at this - make sure coolant level is not low and make sure system has no leaks.
R51 has a stupid layout of the coolant piping on the firewall, where Nissan made it almost all of metal pipes, but in one or two spots connected it with flimsy plastic connections, which tend to become brittle and sprang a drip-leak right on connection… ask me how I know :frowning: