I suspect there was a leak in the heater core and when they turned on their HVAC it reeked of coolant. Hence why they might have bypassed it.

If you do purchase it, I would hook it back up or replace it if necessary. A heater core is nice to have in the event that the engine is overheating. You can quickly cool it down by turning on the heat and letting cool coolant circulate through the system.

Apart from that, I would be listening for lifter tick or any unusual noises coming from the engine bay unless it’s a minor serpentine belt squeal. Also, check the exhaust smoke and see if it’s throwing out coal or if white smoke is pouring out. Those might be possible indications of expensive repairs and parts. If you test drive it, feel how the transmission shifts. If its jerking between shifts or slipping, it might mean that the previous owner neglected to change it or it was damaged. It wouldn’t be worth buying after that.

Good news! I did what you said although I ditched the radiator fittings and got an aftermarket cooler from Amazon and it’s actually Better. I’ve been running the car with low ATF all this time (not too low).

It took me a few jugs of ATF to figure out how to fix the leak which basically flushed the system. That worried me since old transmissions will slip real bad with new fluid.

However, it didn’t slip at all and it Shifts FLAWLESSLY. These transmissions are great. Thanks for the help!