So I bought a stock replacement radiator to run temporarily until my new Griffin (which is on backorder until God knows when) arrives.
This radiator has what I believe is a fitting for a coolant level sensor, which the original radiator never had.
It also has some sort of inlet/outlet toward the top on the passenger side that is capped off with a rubber cap and worm-gear clamp. What is this for? The original radiator doesn't have it. And does that fitting for the coolant level sensor need to be capped off?...

 

Those radiators are somewhat "universal"; they fit LOTS of cars, some of which have the sensor. Usually they come with one installed. If yours didn't, look up newer vehicles until you find one that has it, and buy it and put it in there. Try late 90s early 00s luxury sedans like Caddy CTS or the like. 4th gen Camaro or Firebird might even have one.

 

Here is a pic of my stock replacement. There is something that sticks out about 1/2 way down the pass side. As you see nothing attaches to it and nothing leaks out. It looks like it could be a low coolant sensor and it does not look like it is plugged. I have 2 inlet/outlets at the top on that pass side and the top is for the coolant tank and the one below is from the heater/bypass hose.

 

Yes that is a level sensor. They come installed in new radiators usually.

 

The funny part is how few thirdgens used that sensor and how every stock replacement thirdgen radiator comes with it installed.

All the factory plastic tank radiators have the port for the sensor molded into the tank, but undrilled. Some reason the aftermarket feels they have to not only drill the hole but install the sensor. Seems like it'd be easier to just include a note to drill the hole if your car has the sensor and transfer the contact.

Whatever...

 

Actually,... that is the sensor hole and it is plugged.

ASAIK only the Digital Dash Thirdgens ( Berlinetta and GTA )use it.

 

Thanks, vinny R. That's what mine looks like. I guess if nothing leaks out, then I don't have to buy a sensor. Didn't know about the heater bypass connection since '83/'84 didn't have that...