94 Heating prob.

My truck will not warm up. (ENGINE TEMP or Interior)

We have recently had a very cold wave come through, but it never gets above the "N" in normal. Usually runs around r or m and provides plenty of heat.

So the first thing I do is top off the coolant. (NO HELP< STILL COLD)

Then I change the thermostat...(NO HELP STILL COLD)

I also let it warm up when leaving work....It makes a green puddle in the parking lot. SO I changed the radiator.

Guess what.....NO CHANGE.

I have also installed cardboard to cut off some of the clean air and it has made no change.

What is the deal???

green puddle in parking lot... sounds like you might have a leak at the hose connection to the heater core. or core itself is leaking? is your passenger side floor wet by chance? (no doesnt always mean its not the core)

It was the radiator. It had some holes in the tank.

Already replaced it. But it is still cold.

You said you changed the thermostat, did you change it or did you have someone else do it? If you did it, did you make sure it was put in in the right direction. There is a certain way they are put in. If it is put in right and is working properly, then it could be a couple of things. It is strange that both the truck and the interior (heater) is not warming up. If it was just the truck temp gauge then it could be the temperature sensor or the temp gauge itself. The temp sensor screws in the engine block and monitors the engine (water) temp and sends signal to temp gauge. If it was just the heater I would check to see if both heater hoses are hot when engine is up to temp. If they are then I would focus on the dampers inside the heater box (behind glove box). For both to be cold....not sure. Good luck.

I have heat now. It was gunk in the core.