hardly any heat....

[jakenscott]

First off its a 1998 2.4l, since i bought the car the heater hasn't been up to par. When i start the car in the morning I usually let it warm up for about 20 minutes before i leave for work and as long as i leave the window up ( usually cracked to smoke a cig) its got just enough heat to get to work. If I set still idling it gets real warm, but as i start driving again it cools back off. I thought it might be cause i have the radiator fan straight wired to come on with the key but the temp hand always sets at half way when the car warms up. This morning I unplugged the fan and drove the 20 miles to work with out it running ( the only reason i did that was because it was 15 degrees outside) the engine warmed up to half way as always but i still had hardly any heat. the blower works fine and the temp control seems to work fine. There are no coolant leaks and i just changed the coolant when i replaced the head. I would say the t-stat was bad if it didn't slowly climb up to the halfway point and stay there even on the freeway. What else could it be? Please help i'm a human popsicle!!!!!!
Jaken

[tenspeed]

It's sound like the heater core is not getting full flow. I don't know what you can do to fix it. Check the valve. The core might be clogged.

Use the low speed fan to increase the temperature of the air coming out.

[lilniemo]

On my '00 GAGT I had a similar problem - the coolant wasn't leaking anywhere that we could see. I let it warm up one day for about 15 minutes and when I got in there was no sign of heat at all. I turned the car off and let it sit for a few then popped the cap on the coolant reservoir. It was almost completely empty and mixing in with my oil - fun days right? But from what I read you've already replaced the head so I'm going to go with the same recommendation as tenspeed about heater core. Good luck, try and keep warm! :)

[RazorDX]

Check the hoses leading to the heater core.

Does your fan come on early or stay on? If you have a faulty thermostat, it might not be letting your engine warm up fully. What temperature does your engine operate at? It should stay around the first and second notches on the gauge.

[jakenscott]

It has one of those gauges that has a normal range, it starts at 100 at the low end and ends at 260 at the high end (i think) but the gauge is at half way, (center of the normal range) when the car is warm. I checked the radiator hoses after driving the 20 miles back home, there isn't any pressure on them and they feel cool. It hasn't used any coolant nor is there any water in the oil. Tenspeed could you tell me where the valve is because I didn't know that it had one. I knew older cars had them on one of the heater hoses but i thought newer cars didnt have them. As for the fan it is wired in to come on with the key and run all the time but i drove to work yesterday with the fan disconnected and still had very little heat.

[tenspeed]

It has one of those gauges that has a normal range, it starts at 100 at the low end and ends at 260 at the high end (i think) but the gauge is at half way, (center of the normal range) when the car is warm.

That where it should be. That's around 190* according to my scan gauge.

I checked the radiator hoses after driving the 20 miles back home, there isn't any pressure on them and they feel cool.

That's not normal. Radiator hoses and heater hoses should be hot and feel solid at normal operating temperatures and pressures. The hoses to and from the heater core have to be hot to get any heat in the car.

Tenspeed could you tell me where the valve is because I didn't know that it had one. I knew older cars had them on one of the heater hoses but i thought newer cars didnt have them.

Having a valve of some sort is an assumption on my part. The temperature knob has to change something to get the temperature to change. I haven't torn a Grand Am apart looking for one. Maybe someone who has changed a heater core can shed light on how the temperature is regulated.

As for the fan it is wired in to come on with the key and run all the time but i drove to work yesterday with the fan disconnected and still had very little heat.

I would leave the fan off for the winter but don't let the car idle for long without it. If your cabin heater isn't working and the fan is disconnected, it could over heat the engine quickly. Maybe a fan switch would be a better way to shut it off when you need to.

Or you could repair it so it works as designed ie comes on when the engine gets too hot.

[rixGAphx]

...there isn't any pressure on them and they feel cool....At the very least, there should be some noticeable pressure.
Since there's none, there must be some sort of leak-to-atmosphere.
Since you also don't lose any coolant, the culprit would most-probably be a faulty pressure cap on the reservoir.
...where the valve is because I didn't know that it had one.
I knew older cars had them on one of the heater hoses but i thought newer cars didnt have them.Tenspeed is thinking like an old guy, and he's made the same mistaken presumption I made relative to the GA's heater circuit.

You are right, there is NO valve in either of the coolant lines that serve the heater core; this is true for the GA's (at least '96+) and msot modern cars.
The heater core has full heat at all times.
Output temperature is 'balanced' *slightly* by routing of air thru the AC evap coil, with the compressor coming 'on' as required (particularly in the vent-and-floor mode, where cold air may be directed to your face, but warm air goes to your tootsies).
But mostly, the system balances how much cold outside air is drawn-in, versus proportion of warm cabin air is recirculated.
All of this 'balancing' is done with little doors ('dampers') in the ductwork, which are controlled by the knobs and actuated by vac tubing and diaphragm 'motors' at the dampers.

Your fresh-air intake door may be stuck open, or its vac motor isn't actuating it properly.
It's warm when you idle, but cools-down when you start to move.
Vac is strongest when you back-off the gas after running at road rpms (say, 2500+); it is second-strongest at idle, when the throttle plate is closed.
It is weakest when you open the throttle to accelerate or even just drive at constant speed.
I would *guess* you have a vac leak at either the control panel (knobs) or at the damper motor; a spring is pulling the fresh-air damper open, and you only have adequate vac to close it when idling, and during the few seconds when you back-off the throttle to approach a stop sign or redlight.

So crawl under the dash and examine those tubes and dampers, and also pressure-test the system.
AutoZone has a pressure-system tester for loan.
You might need a new $12 pressure cap. Only tighten the cap as much as an average woman can easily do one-handed; any tighter and you will damage or distort the delicate rubber sealing washer that maintains pressure.

Good luck,
-Rick