lemme see

you have your exhaust valve(or valves for multiple valve engines) which open and allows the exhaust gasses to pass out the cylinder head to the exhaust manifold or headers

Yes, there is a head gasket that if leaking, could allow combustion gases to enter but not just exhaust gases.

That is why I focused on on 'exhaust leak"


rule of thumb is simple

if coolant is going down, and it's not leaking from the radiator, reservoir, freeze plug, hose, steam pipe or any of the fluid carrying pipes, then it's going out your tail pipe and time to pull the heads, get them cleaned up and replace the gaskets. Of course there could always be a cracked water jacket which isn't a good thing

 

if your not seeing a leak or have coolant in the oil then, are you getting wet spots on the passenger side floor? other than it going out the exhaust like tig says, heater core is the only thing i can think of.

 

No tig it's not leaking out of any of those that's why I'm breaking her down and checking the heads for cracks and/or bad head gasket. And no there were no wet spots under the passenger side. The water jacket? Not sure yet. I should hear something tomorrow. Thanks again tig and craby for the help. I do believe this is really my last option to tear it apart and see. I was hoping I wouldn't have to but I want save her before anymore damage is done.

 

My money would be on the head gasket

Now that you are in there, you may as well spend just a few more $$$

oil pump
oil pan gasket
front seals
timing chain kit
plugs and wires
get the heads cleaned and checked. You don't have to get them ported but enlist a machine shop.

yes, you may be looking at an extra $500-$750 but it's money well spent.

You then have a freshened up top end as well as new oil pump and she should give you lots of extra miles in return

EDIT: also check all the vacuum lines and small hoses and fixtures while you are tearing it down. $20 worth of various size hoses and tubes is great to have in your garage