When my Z is at a stop, the heater blows cold air. However, when I'm moving, the heat works absolutely fine. I have the same issue no matter if the I have the heat set to automatic or manual settings. Has anybody experienced similar issues or could someone possible shine some light on what my problem might be?

2004.5 350Z Touring

 

Pulling this from my *** and making a total guess.

When sitting at a stop with the car at an idle, it might not be pulling enough fluid through the heater core, when you start moving and the RPMs go up, it might be drawing more fluid through the heater system.

Maybe air in the lines? have you had any of your radiator hoses off before? maybe low on fluid? does your car ever seem to run hot?

Again, just pulling this from my ***.

 

Had this problem last year when I bought my car. Turns out there was air in the line. The bleed screw for it is on the passenger side behind the engine. Sorta near the battery cover.

 

Most likely air in the system. Could be from not bleeding it good enough if you just did some work on it or could be a bad radiator cap that is not holding correct pressure.

 

Thanks for everyone's input! I'm going to bleed the system and replace the radiator cap this week. Hopefully that does the trick!