They use plastic quick connect fittings with rubber o-rings that shrink in cold weather and leak. New and improved replacement hoses have two o-rings that shrink and leak. The best fix is to remove them and use plain bulk heater hose cut to the right length, and regular hose clamps. Leave the old hoses on the van to tie the new hoses to.
Because the nipples for the rear heater core are on the bottom, burping the air out is very difficult. What I found works the best is warm the engine to build pressure in the cooling system, (or better yet, use a pressure tester to pump the system up to 15 psi), use a hose pinch-off pliers on one of the hoses, and loosen the hose clamp on that same hose next to the heater. Pressure will escape by the coolant traveling into the heater core and forcing the air out of the loosened hose.
Please reply directly to my personal e-mail if you have more questions. This site is going through changes and right now I'm not getting the automated messages telling me when you post a reply. Include the year and model of your vehicle, the problem, and your user name.
Monday, November 15th, 2010 AT 4:09 AM
By the way, the rear heater will only blow cold air until that air is burped out. Until that is done, no hot coolant will flow through it. Usually, if you don't burp the air out, it will work its way out over time and eventually start to work on its own, but that could take days or weeks and many warm-up cycles.