Heater problem on '96 3.8L Camaro

Hello everyone,

I have a '96 Camaro with the 3800 engine. About a month ago I noticed that my heater doesn't work at all. I've tried flushing the heater core, replacing the thermostat, and flushing the entire cooling system. I removed the heater input hose from the engine and started the engine. The water rises slowly and eventually trickles out, but not as much as I would expect if it were working properly. I recently took the car to a service center to diagnose the problem and they claim that combustion gases are present in the radiator - which means a bad head gasket, cracked head or block. The car runs great with no visible symptoms of a problem.

My question is this: Is it likely that the heater problem is caused by a bad head gasket, or could it be due to a bad water pump? The car doesn't overheat, which means the water pump is working at least somewhat, but could it just be "weak" and not providing enough pressure to force water through the heater core?

Any help is greatly appreciated. I'm starting to think about trading it in since winter's coming fast and I'll need a heater soon. Thanks in advance!

In case anyone was wondering, I finally got the heater working. I replaced the water pump since it was near the end of its life anyway, and tried flushing the heater core more thoroughly. This gave me SOME heat, but not enough. I finally replaced the heater core this weekend (cost $80, took a couple hours) and now the heater works perfectly. I also broke the old core open to see what was going on inside and found that it was about 90% clogged with orange/brown crud. The moral of the story is that the coolant should be replaced before hitting 100k miles (I didn't) because the Dexcool seems to go bad around there.