Thanks for the info.
The coolant tank on my GMC is pressurized and is the only access point to
add coolant to the cooling system. So far no leaks are visible. This may be
good news!
"Floyd" wrote in message
...
needed a drop of coolant added since it was new! I added some coolant and
could see no visible leaks underneath tonight. Will check again in the
AM. If I see leaks...........it looks like it goes in the shop tomorrow
AM.

On many vehicles the coolant tank also acts as an expansion reservoir that
accepts coolant that is pushed out of the radiator when it is heated up.
Coolant may also be sucked back into the radiator when the engine cools.
It is possible that your radiator may only be half full....after you fill
the reservoir, so a heat cycle may pull coolant from the reservoir and
make it look like you still have a problem. A few heat cycles, and
keeping the reservoir topped off, will let you know if you still have a
leak somewhere.
Not seeing any coolant leaking or driping from the engine is good, but if
you have a head gasket leak or cracked head/block the coolant could be
going out the tailpipe. Maybe if there is a coolant leak into a
cylinder, that sparkplug will look different.