How do I know if my thermostat is stuck open? The engine temp runs at the bottom all the time, except when sitting in traffic. The engine driven fan is even removed. Car has a code 16 i think for temp too low.

The thermal sensor for the aux fan is broken, fan was rigged over the summer to run constantly.

How can I test a stuck thermostat?

 

you can test the thermostat but that would require removing it, when was it last replaced?

 

it is completely possible a previous owner installed a fail safe t-stat. when those fail, instead ofbeing stuck close, they stick open so there is no overheating. however ti dont think that is the case cause even if the t-stat sticks open, your car will eventually warm all the way up. i was having cooling issues in my old car and decided to pull the t-stat altogether. the car took a very long time to heat up but it did eventually. one main factor in all of this is how is your heat worker? that could help diagnose the issue

 

never done one on these cars, but if in doubt... might as well change it... t-stats are generally 10-20 bucks and pretty easy to change... change that sensor that you said was bad too and any shoddy stuff done to rig out the aux fan to run all the time... or add a switch that you can control... f-body guys use switches on their fans a lot

 

If blows heat from blowers, could just be water temp sensor

 

I had almost the exact same problem, and my heater would blow hot. I replaced the water temp sensor (the one next to the firewall, NOT the one near the radiator) and it fixed it right up.

 

The heater hardly works even when the gauge reads normal. It will come up when sitting in traffic, but once I am moving well it goes back down. I hooked up a scanner to it and it read between 130-150 degrees. Way too cold. The fans arent running, and I have cardboard over the radiator. The ac condensor is removed. Last winter I just had cardboard over the radiator and it warmed up, but the heater heat was still a little low. Then in the summer I would remove the cardboard and the car would heat up as normal.

I did buy a thermostat, but its underneath the timing belt as I understand, and i already replaced the timing belt this summer. Im not tearing that **** apart again.

I havent noticed any fuel mileage loss, I would just like to have heat in the car. Last winter, I flushed the heater core and a lot of crap came out. It helped a little.

Thanks for the input guys!

Oh and I am an f-body guy, and I do use a switch to control my fan on my drag camaro. I have the sensor/switch, just havent put it in yet. Don't see the point yet if the motor doesnt get warm enough to even need the fan!

 

There must be a lot of gunk in my cooling system. My heater core is clogged again. Hose going in is hot, but the hose coming out is ambient.

I let the car idle yesterday for 10 minutes and the heat rose up to 204*. As soon as I started driving, it came down to 157*. The power was smoother when it was this warm.

One thing I was worried about, was maybe the sensor is all mucked up and isnt reading the true temperature. And the motor could be much hotter than I think. But the ignition timing has stayed the same, so apparently there isnt any detonation. If the car has a knock retard function anyway..

 

How did you know if your heater core was clogged? And how did you unclog it?

 

Well I would feel one hose hot and the other not. I just hooked up a peice of hose to the core and blew water from a garden hose through it backwards. A lot of crap came out. I think it was silicone in the antifreeze that separated due to it being too cold. May have been the wrong antifreeze too.

But now I don't have any coolant flowing through the core, so I'm going to make a new post for that.