It sounds to me like you plan on going all the way from the engine to the rear heater core, and depending on why, that may not be the best solution.
These vans had a lot of trouble with the o-rings at the rear quick-connects to the heater core. They shrink in cold weather and leak. You get a green puddle on the ground next to the right rear tire. When these vans were under warranty, we were obligated to repair them with factory-approved and supplied parts. The new hose assemblies had TWO o-rings, ... That shrank and leaked in cold weather! The new, superceded parts did not permanently solve the problem.
When the vehicles were out of warranty, the much more effective repair was to cut the crimps off the hoses at the front, right behind the engine cross member, (under the front passenger's foot area), then cut the hoses off. At the rear, just pop the couplers apart. Don't even bother to remove the old hoses. Use new bulk heater hose in place of those you just disconnected. At the front, just slide them on and use regular hose clamps. At the rear, the hoses will slide onto the nipples of the heater core but you have to watch that they don't kink from making such a sharp bend. Use tie straps to hold the new hoses to the old ones.
Leave one of the hose clamps loose at the rear. If left to itself, it can take weeks of driving before the air will burp out of the rear heater core sufficiently for coolant to flow. That's because it sits up so high and the inlet and outlet are at the bottom. You can use a pressure tester to pressurize the cooling system, but I just let the engine warm up to build pressure. Use a hose pinch-off pliers to pinch the hose with the clamp that's still loose. The pressure will force coolant into the heater core through the other hose, and the air will sneak out by the loose clamp. Tighten the clamp, refill the reservoir, and you're done. Don't get excited if you don't get good heat right away. If there's still some air in there, it will work its way out over time.
Friday, December 16th, 2016 AT 12:43 PM