HAVING HEATER ISSUES!!!

[02pathfinder]

A few weeks ago I noticed that after a few minutes of warming up my car, the temp gauge never moved (which has always been my indicator that I can turn the heat on). Got in the car to head to work and turned the heat on and it was only blowing out luke warm. As I started driving, the temp gauge started to rise and the heat started coming out hotter. Then I noticed when I got to a stop light, it was back to coming out luke warm (temp gauge still where it should be). So the final consensus is that the heat only comes out hot when the car is moving (foot on the pedal, revving engine). There doesn't seem to be any issues anywhere else. All the speeds for the fan work. The only issue is that sometimes it makes some weird noises. Does anyone have any ideas as to why this is? Is it the blower motor not working properly? Blower motor resistor? Any ideas or help is greatly appreciated. As it figures this happens at the coldest time of the year

[atraudes]

Sounds like your thermostat is bad. Fortunately for you it got stuck open instead of closed and causing overheating. The thermostat hanging open means the cooling system keeps circulating the fluid instead of being able to hold the proper warmth in the engine. Your fuel economy will also suffer because the ECU will force a richer blend in an effort to warm it up quickly. Rich conditions are bad news for the catalytic converters.

The bright side of all this is the thermostat is pretty straightforward to replace and isn't pricey. You'll want to do a full coolant flush with a detergent as well if you haven't done one recently for good measure. Pulling the thermostat means removing the lower radiator hose, which is likely due for replacement as well. I recommend the Prestone AF555 Low Tox Antifreeze coolant and Gates for all hoses. Let me know if you need help finding the part numbers for the hoses.

Good luck and just post back if you have any other questions or concerns

[02pathfinder]

Awesome! Thank you for your help. Seem like a pretty easy and straight forward job I can do myself. Hopefully I can get a fairly warm(er) here sometime soon to try and tackle the job. Seeing as I have no garage and will have to do the work outside. I need to change the oil cooler O-rings as well. So I might as well get it all done at the same time.
Thanks again for your help!

[kentai3838]

Hi there,

I have a similar issue with my 2002 Pathy. There is only luke warm heat from coming out either at idle or driving. On a very cold day such as 10-15F, I can't feel any heat at all. The temperature gauge stuck at the bottom most of the time; occasionally, it moved just a bit past "C". Also, I remember in the summer, sometimes, when I just turn on fan, heat will come out even the temperature knot is all the way at cold. I have to turn on A/C to stop the heat.

I read the forums and tried to park the car sloped ramp and revved up with radiator cap off - doesn't seem to help.

Is it thermostat issue too? Any pointers?

And by the way, there is a couple codes p0506 and p1456 (I am still reading thru other posts on the stalling at start up problem. Just have to give a some gas on startup to prevent it from stalling; otherwise it runs fine.)

Thanks in advance.

[Leo1998]

On those cold cold days try putting cardboard in front of your radiator, that should help.

[atraudes]

Is it thermostat issue too? Any pointers?

Certainly sounds like it!

On those cold cold days try putting cardboard in front of your radiator, that should help.

That would help warmup, but it'll still drop its temperature too far while running. You'd have to keep putting it in, taking it out, etc. to keep it at the proper operating temperature. By doing so to any extent, you'd only be imitating what the thermostat is supposed to be doing anyway

For your codes, click here for P0506 and P1456. You'll probably care more about P0506 initially since it will (should) fix your idle problem.