Thread: Intermittent heat problem with 2005 GP NA

Yesterday I noticed after several minutes of driving that I had no heat coming from any of the vent. I checked the dials, the blower were working good but no matter which vent or what temp setting I used, I was getting only ice cold air from outside (was about 20'F that time) Also I noticed my car temp gauge was reading close to warning, normally it should be close to the middle.

After I made a quick stop at a store (about 20 minutes), I checked and the hot air was flowing once again and the car temp remained at the normal range for the rest of the night. I checked today, it seemed normal after letting the car run for a few minutes (was about 30'F daytime and last checked 15'F).

I thought it may have been sticky thermostats but my Dad said the heater core is connected off engine's fluid and not from radiator or reservoir so if the thermostats was stuck, the fluid would still be going through heater core.

So what could have been the issue?

Recent repair: transmission lines to the radiator had to be replaced, the old one was corroded and started to leak fluid. Also oil changed. Unfixed issue: AC doesn't work, leaks in the compressor and there's OBD warning about cat converter, probably bad O2 sensor.

TIA for any suggestion what to look for!

Originally Posted by industrialfish

First make sure your coolant level is good, then bleed the air out of the coolant system by running the engine until hot while the brass bleeder screw (7 or 8 mm) on the thermostat housing is open. Once it stops bubbling and starts streaming coolant close it again. You may need to repeat a few times over a few days.

Will try that

Where in MI are you, btw?

the thumb area, thankfully far from Detroit area and away from Flint and Saginaw.

Originally Posted by industrialfish

Also if the cat code is P0420, on a 2005 your cat is probably on it's way out.

Bah, that is well over $100 plus labor. Should I get the O2 sensor replaced at the same time? Since I don't have emission control in where I live, that is only in Detroit Metro area IIRC so I should be OK ignoring it for a few months.