Percolation? Heat soak? Don't drive during summer??
Sorry i just finiahed with my patients for the morning and then read all of the party that I missed lol.
I'm also sorry if anyone is getting upset in the thread, and hopefully it starts to cool down in here. (See the pun there :D)
As some suggested with my car getting hotter in the garage while I dont want it to happen unfortunately it did. Ive gone through the cooling system as much as i can, the only thing that could be suspect is the block itself. There was some gunk built up in the cooling passages (correct term?) In the block, I got out what I could when we took the engine apart though.
My garage was also gets blazing hot when I run the car in it, even with the garage open. The other day there was probably a 15-20 degree swing between the garage and outside temp. I kept stepping outside the garage to actually cool off and get some air flow... and its 100* outside...
Your cooling system is likely OK - a shorted coil negative will stop an engine in it's tracks, and a spotty short can act like what you were experiencing. Hotter temps can soften wire insulation and cause the short to come and go with heat/cool. The fact that your ignition was firing a buzzing spark is the evidence that the short was likely not a good solid direct short to ground.
The thermostat will only control the min temp, as YR said. It won't stop an engine from going over. A lower temp thermostat in some cases CAN lower the operating range a bit, but not because it's a lower temp thermostat - it's because the higher temp one sucks (doesn't fully open at the rated temp, but only partially - can make a 195 stat run an engine at 200~205).
An engine with an iron block and iron heads with at least an 8 psi rad cap is going to be OK until it starts to go beyond 230 degrees. It will begin to lose performance long before that, but it's unlikely to experience damage in that range. Idling at 220 is not comfortable, but not major cause for concern unless it happens every time you hit a stoplight.
Typical rule of thumb is that if it gets hot at idle, but not when moving then it's either water pump or fan. If it's outside and hot at idle, pop open your hood. If temps drop, it's most likely the fan/shroud or combo. Electric fans will move a LOT more air at idle than any crank-driven system could, but you'll want at least a little bit more electrical experience before taking on that project. I'd still do your A/C before the cooling system. If it gets hot with the A/C on at over 20mph, then the cooling system will likely need upgrades (and the A/C won't work as good if it gets hot, so it'll be easier to convince the wife!).
Looking forward to hearing if she stays running on the next trip.