Heater problems and coolant reservoir

[MNGuy]

Hello

I spent some time reading previous posts before I posted this, but I'm still a little in the dark, and hoping to make the cheapest repairs first.

My car provides great heat when I'm pressing the gas pedal, but when I take my foot off or idle the air from the vents is very cold. I topped off my coolant in the radiator and the reservoir tank. The problem remained.

Previous posts suggested thermostat replacement, heater core replacement or air bubbles, but I didn't see any posts where these solutions fixed the issue.

Here is my question: When my car is running and I open the reservoir tank, how much activity should I see in the coolant?

Currently I get a small bubble every couple of seconds. I'm wondering if I have a clog somewhere. Am I on the right track? Other suggestions?

The car never overheats, and the warm air is available within a few minutes of starting the car (if I'm pressing the gas of course.) Last mention: frequently this summer I could feel very warm air blowing on my right foot as it rested on the accelerator. What is that all about?

Thanks.

[robo_geek]

I do not believe that the overflow tank is telling you anything.

You should not see much activity in the reservoir. Remember that the reservoir tank is closed off from the rest of the system by the radiator cap. Coolant should only go into the tank when the pressure is very high when it's hot, and some should be drawn back in when the system cools down.

With respect to the 'hot foot issue':
While some cars shut off the flow of coolant through the heater core with a valve, nissan makes it so coolant goes thru the core all the time. How much heat, and where it comes out is controlled by doors in the blower housing. These are controlled by little motors. The heat by your foot means that the door was sticking, the little motor was freaked out, or there's something odd like a hole in the air duct.

The fact that the heat comes up quickly tells me the thermostat is good. I would suspect that the heater core is blocked up. I would do a reverse-flush of the cooling system and make sure the hoses are in good shape, as a collapsed hose would provide a restriction.