1992 Chevy Caprice is leaking antifreeze at or near the firewall in the engine compartment. Is this from the heater core? How do I access it?

Your heater core is leaking. Replacement of this part is a big job and should be done by a professional.

Those two hoses are probably the heater lines, that flow antifreeze to the heater core under the dashboard. One of those hoses most likely has a leak and needs to be replaced.

the fan you are referring to is inside the trailblazer on the passenger side behind dash near floor wall? If this is the case it is the heater core and needs to be replaced by a professional. If is is under the hood in the engine compartment it is the water pump in need of replacement? thanks good luck on the heater core..

You have a coolant leak, either in the heater core, or from the heater hose that feeds heated coolant to the core.

It sounds like you probably have a leak in your heater core. Replacing a heater core can be a difficult job. If you decide want to try it I suggest you get a shop manual to help you out. I can give you a relatively easy temporary fix that will stop the leak until you have more time to fix it or you can take it into a shop to have it done. The down side is this fix will temporally disable your heater. Wait for the engine to cool. Open the engine compartment and look all the way in the back between the engine and the firewall. Find the 2 heater hoses that pass through the firewall. They should be about 1 inch in diameter. Undo the hose clamps and disconnect them from the firewall. Get a short piece of metal tubing about the thickness of the inner diameter of the hoses. Use this metal tubing to connect the heater hoses together and clamp them using the two hose clamps. Now the antifreeze that would normally circulate through your heater core will instead circulate through this loop and not enter the passenger compartment. If you can't find a short piece of metal tubing to do this fix you can completely remove one of the heater hoses. Then take the other heater hose and connect it to location near the engine where you disconnected the first hose. Save the first hose so you can hook it up later when you do the more permanent fix. Make sure to position all hoses such that they aren't resting on any hot surfaces. I hope this advice helps you out.

Heater Core REMOVAL & INSTALLATION Fig. 1: Heater core removal for 1987-88 models
Fig. 2: Heater core removal - 1988-96 models
Without Air Conditioning

1. Drain the cooling system to a level below the heater core. CAUTION
   When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.
   
2. Disconnect the coolant hoses at the heater core tubes.
3. From inside the passenger's compartment, remove the 7 screws that secure the heater core access cover to the plenum chamber. Remove the cover. On some models, it might be easier to first remove the glove compartment.
4. Remove the heater core.
5. Installation is the reverse of removal. Replace any damaged sealer.

With Air Conditioning Fig. 3: Disconnect the heater hoses at the firewall
Fig. 4: Remove the glovebox
Fig. 5: Remove the heater core access cover from the plenum chamber
Fig. 6: Remove the heater core from the vehicle

1. Drain the cooling system to a level below the heater core. CAUTION
   When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.
   
2. Disconnect the coolant hoses at the heater core tubes.
3. Remove the glove compartment.
4. Disconnect the temperature and function cables.
5. From inside the passenger's compartment, remove the 7 screws that secure the heater core access cover to the plenum chamber. Remove the cover.
6. Remove the heater core.
7. Installation is the reverse of removal. Replace any damaged sealer.

Check the heater control valve and the hoses where they go into the firewall. If the leak is not there, then the most likely problem is a leaking heater core. You need to look carefully to find the source of the leak before you can repair it. Use a flashlight, mirror or whatever is necessary to do that. If it is a hose, use extreme care removing it from the heater core connection. best to cut it off with a razor blade. If it is the heater core,most times it will make the passenger side rug wet. If it is the core, it isn't an easy job and I'd consider either getting a haynes or chilton manual to guide you, or, have a good shop do the work.
good luck

Yes he has to drain the system. It is located at the bottom of the dashboard. If looking into the engine compartment, you will see whre the hoses connecting to the heater core go into the cab at the back firewall.The heater core is just inside the cab.

Find the 2 hoses that go into firewall, for heater core, remove them & join together with a piece of copper pipe or similar & top up your coolant, you should be o.k.

your heater core has probably sprung a leak.does the smoke smell kinda sweet?....check the floor in the front where the floor mats are for moisture or even puddles of antifreeze.(the replacement of a heater core can be very expensive as the entire dash usually needs to be removed to access the heater core)also look under the engine near the firewall for antifreeze drips.