Bruce, I run my
LZ with 'Skips' water pumps and coil, with no thermostats, in the usual 80+ degree temps here in central Florida, where the duration of the 'red' traffic lights is sooo long, you can almost feel your metabolism changing (
due to aging) while you wait for the light to change...
I've seen the temp gauge climb up to the 220 range as well, and, just like you said, it drops back to the 160 to 180 degree range almost as soon as the car starts moving. One thing I haven't experienced with the
LZ is a loss of coolant after shut down. I run just water with a rust inhibitor additive in the cooling system.