This is the pipe that connects the lower radiator outlet to the heater core and (on '83-85 12A's) the Beehive. I took mine off to see if it could be cleaned up, and found it's totally blocked with rust and crud. No water will pass.

What's the best way to replace this? Do I need to search for another used one and hope it's cleaner, or is this a common job for a radiator shop?

Or should I just get a long rubber hose to replace it end to end?

 

I'd go with a used one. They don't tend to rust too bad like your experiencing.

The other option would be to try so loosen the crud up with something like CLR and then blast and power coat or paint. I'm not a fan of using a hose that long.

 

If its blocked I would try straightening a coat hanger and working it through and chipping away at it. How far in is the blockage? You might be surprised as how quickly it loosens up.

 

Compressed air might unclog it too. I'd try to salvage that piece if possible.

 

I ended up just replacing the same pipe on my FC with HPS silicone heater hose: https://hpsperformanceproducts.com/p...-overflow-tube

This should avoid further rust issues, and would require you whip up some bracket or loop clamp to hold it in place, and a 't-fitting'.