Still consuming coolant, still approximately the same amount.
Did a little more inspection this past weekend.
Closer look at accessible hoses, clamps etc. Still can find no leaks or evidence there. Check hoses and steel tubes on firewall for heater core. Checked hoses going to and from there to the engine, waterpump and thermostat on top, other side of engine - nothing seems to be leaking there.
Unbolted fill bottle and lifted up and inspected under it. No leaks seen or noticed there.
Tried with little inspection mirror (like dentist's mini mirror on a long thin handle) to look behind alternator and water pump area (front cover area). Tried to illuminate well, good lighting in there, with a flashlight and a trouble light - but very difficult to see much of anything in there. Nothing noticed really leaking.
Looked under car, and up and towards the block thru the passenger side front wheel well. Managed to go in thru wheel well, with arm, with a 1/4" drive small ratchet and deep socket / short extension and check tightness of clamp on 2" rubber hose going from block to radiator. But looked tight enough anyway, and not leaking.
I am guessing that this leak is a slow seeping leak from the front engine cover gasket, and seeping slowly down onto exhaust tubes and cat convertor in that area. The steel sheilds and heat covers over the cat convertor and exhaust tubes in this area make it hard to see any leaks or wet there - plus it is probably evaporating / turned immediately to steam - so slowly that you don't normally notice or smell the steam from the evaporating liquid.
When it is cold, a little steam seen once, coming from front of car, sort of like out the front radiator, on that side.
I tried to look in and check for a rad leak - but noticed nothing.
After hot highway run, parked, and opened hood, and monitored. Level in bottle drops as engine cools - i.e. as coolant cools, contracts, pulls in missing fluid to replace that which seeped or leaked.
From 1/4" down at park ... to 1/2" down as engine cools - one hour later.
Then listened carefully and looked with flashlight as engine cools.
Hard to say for sure ... but every 2 minutes or so, as engine is cooling, I hear a very faint "drip ... sssss" possibly as mini drip falls and hits hot exhaust part and is quickly vaporized. It is so silent. Not sure.
Continuing to monitor. Would LIKE to be able to try tightness of all front engine cover bolts - but cannot get to them at all.
If gets worse - I am considering asking mechanic if possible to:
1. Go in with one of those mini inspection cameras / on long flex end / and try and look.
2. Ask if possible to pull off necessary accessories there - Alternator, AC
pump etc. to get to the front cover bolts and check tightness.
3. Do nothing, but just try find leak for me - tell me if/where it is leaking.
And then we will discuss.
4. Over pressure the system and test that way. Pump it up to say 25, 30 PSI
and leave it that way for several hours and see what gets wet.
Tough one to figure out ... I may just continue adding, and monitoring, and do nothing, and it will eventually get worse and show me itself where it is leaking that way.