I noticed that the two metal coolant lines that come down from the engine and head towards the rear are rusted very badly. What's the fix for this? Dealer? (don't want to go that route...) Junk yard? aftermarket?

 

There are several fixes:

1. Buy the new part from the dealer (over $200)
2. Dorman makes that part and I've seen it on line for around $100

In both cases, installation is very labor intensive. I had a really hard time fishing the old one out even after cutting off parts of it. From either the top or the bottom. I am guessing fishing the new one in involves removing a lot of stuff in the engine bay. I haven't tried it.

3. Cut off the rusted parts and replace with heater hose. Careful to shield it from exhaust.

4. Get rid of it altogether. Get the heater hoses for a non-rear AC application. You lose rear heat function. This is what I did. Never used rear heat anyway.

 

Try Rock Auto. They have it for about $77. Dorman makes it, part no. 626-300

http://www.rockauto.com/catalog/raframecatalog.php

 

98 Dodge Grand Caravan. I had a leak in my radiator, replaced the radiator, only to find that my rear heat lines were corroded, a mechanic friend of mine said that I could just "U" off the rear lines leaving me with no rear heat. Which I'm fine with, but since he did that my van overheats (red line hot) within 5-10 minutes being driven. (doesn't overheat at all when in park) I replaced the thermostat, the water pump and had the radiator rechecked. what would make my van over heat so quickly? I'm no mechanic, but others that I try to explain this too are at a loss as well

 

isn't this part for the rear of the heater lines?

 

Have you verified you don't have an exhaust leak into the coolant. Buy or sign out a test kit from many parts stores. Here's an example:
BTW - usually best to open a new thread instead of bringing back an old thread. How? Click "New Thread" at upper and lower left of opening page.