It is very good you found the problem!!!
I had the worst experience with overheating in my 91 240sx. I was new to cars at this time. Car started overheating -> I replaced the thermostat, didn't work so I replaced it again because I have heard of them coming bad from the manufacturer. When that didn't work I just started throwing parts at it (water pump, radiator) because then I was too stuborn to take the car in to the shop. Finally took it in, they replaced the thermostat (despite the fact I told them I had done that twice) and told me it was good. Car overheats again, take to another shop, they claim they fix it... Overheats again. So one day I rev it hard in the driveway and see white smoke out the back. Burning coolant, why could the shops not find this? We just swapped the motor because a local J/Y had a KA24DE for 500 bucks with proven good compression. Sorry it's kind of off topic, but it was madness...
