Coolant leak

[05Coupe]

So I have a weird problem. I'm loosing coolant at around 1 gallon per 10-14 days. I have exhausted all diagnostics to find it, but still it leaks.
1: I've replaced the thermostat housing that was seeping onto the block with an aluminum housing new thermostat and new connecting hoses to the waterpump and heater-core.
2: I've pressure checked the system up to 32psi, double the 16psi the system is supposed to hold. No pressure drop.
3: I've removed and pressure tested every coolant line, no leaks.
4: I've changed the oil, no coolant in oil.
5: I've pulled all 6 spark plugs, no build up nor corrosion.
6: I've scoped the combustion chamber, no residue at all.
7: I've visually inspected the block and as much as I can with a video scope, no build-up or puddles.
8: I've disassembled the exhaust and found to sign of coolant.

My only assumption is that a portal has developed in my engine and is transporting my coolant to another dimension......

Any ideas where it could be going would be appreciated.

 

[Dino Dino Bambino]

You either have a very small leak from somewhere and the hot coolant is evaporating before you can see it, or the expansion reservoir cap isn't holding pressure allowing coolant vapors to escape.
Your best chance of finding any coolant leak is immediately after you shut off the engine when it's hot. Your nose should be able to trace the smell and pinpoint the leak. If there's no obvious leak anywhere (including the heater hoses under the intake manifold and the heater matrix under the dash), try replacing the cap on the expansion reservoir first. Since you aren't finding any leaks by pressurising the system, I suspect that's the most likely culprit.

 

[86GT351]

Radiator Cap or coolant line beneath the Intake Manifold. No teasy to see.

 

[05Coupe]

So I think I found the culprit. The outside was just fine, but the inside was a different story.