Radiator lines to rear heat are leaking

FWD • AUTOMATIC
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TANORDSTROM
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I have a 1999 Dodge Caravan. The radiator lines going to the rear heat need to be replaced because they leak. Do you know where they connect to the front of the vehicle so I can replace them?
Apr 21, 2011 at 3:26 PM
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CARADIODOC
  • ✓Experienced Mechanic
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You can get to the connections right behind the front cross member, but don't waste your money on factory parts. Both hoses have plastic quick-connect fittings with rubber o-rings that shrink in cold weather and leak. The new superceded "improved" part, which is probably already on there, has TWO rubber o-rings, . . . that shrink in cold weather and leak!

When these were repaired under warranty we were required to use only factory-approved parts. When they were out of warranty we were free to fix it properly so it wouldn't start leaking again. You can leave the old hoses bolted to the bottom of the van for convenient tie points, but disconnect them on the front and rear, then run bulk heater hose with regular screw-type clamps. Sorry I can't remember the diameter of the hose. The front pipes and rear heater core tubes will have creases, (for lack of a better word), that will prevent the hoses from sliding off. I don't think they'll slide on very hard but if they do, spray a little Silicone Spray Lube on them. That makes rubber hoses slide over metal tubes real easily.

To burp the air from the heater core, since the tubes come out the bottom, pressurize the system either with a pressure tester or by just warming up the engine, then pinch one of the hoses and loosen the clamp on one of them so the air has to travel through the heater core to get to the loosened clamp. You might have to do that multiple times. If you don't bleed the air that way, you won't have rear heat until the air works its way out on its own. That can take a week or more but it will happen if you're patient.
Apr 21, 2011 at 3:50 PM
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