I have a 86 Camaro Berlinetta. I just notice the passenger and rear carpet is wet under the mats. I dont smell any coolant and I dont have an ac or sunroof. Windows been rolled up and it has rain this last week. The car sits on level ground. Dont know why it would it be wet in the front and the back? No wetness on the sides. Does anyone one know what could be causing this? I dont want my car to start rusting out. I have notice my heater is not putting out the really hot heat like it used too but it still heats up though

Thank you

 

Check the coolant reservoir bottle ensuring coolant is not being lost.
Front windshield could be leaking
Door/window weatherstripping could be cracked or dry rotted.
Best troubleshooting trick would be to hit an automatic car wash and use a flashlight under dash, window(s), and where ever else you could see and check for leak(s).

 

IF,

you are sure that it's not coolant (heater core) and are absolutely sure that it was dry before this week, that it did not rain, then that leaves it to a messy passenger. Logic leads you nowhere else

I know on one of my cars I had passenger compartment water because the drain underneath the wipers got clogged and the well filled with water ultimately entering into the passenger cabin. I don't know if 3rd gens have such a drain but if you're sure that it's not from the heater core, and that there were no messy passengers, then you might want to check out the drain

 

Check to see if your firewall is rusted out. I had an '83 camaro with the same problem and when I peeled back the carpet, the firewall was rusted out and water was coming through.