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No flow to heater core


Old 11-04-2009, 01:07 PM
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Default No flow to heater core

Hello! I ahve searched this forum for a solution, and the eBahn, here goes. We have poor heat. We have heat, but low. I have flushed, etc etc. The radiator and the coolant are now new (radiator was leaking), and a couple years ago I replaced all the front motor seals water pump thermostat etc. The problem started before this. The vehicle stays at the same temperature, not matter what I do (the thermostat and water pump are fine). The oil temp stays the same too. So here is the problem. I went out to backflush the core, and did get some flaky stuff out, but not so much that I was really concerned. The flow was fast, in both directions. So, great. I hook the hoses back up, leaving the outflow open a bit to bleed. Nothing much comes out.

So, I pull the supply tube. The problem is that there is little supply to the heater core. Has this problem been discussed previously? And if so, what should I do?

I plan on draining the system, and then hooking up the garden hose to the supply hose, and backflush that. But I do not know the circuitry. Any ideas will be helpful.


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Old 11-06-2009, 05:10 AM
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No replies? Oh well. If I find the solution, which may be the root of many of the issues I haveread here, I'll share.
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Old 11-06-2009, 01:09 PM
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Try removing the three screws holding the plastic coolant tank, then lift it as high as the hoses allow, with the filler cap off, and see if you begin to get coolant flowing out of the heater supply hose.
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Old 11-20-2009, 06:21 AM
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I had the same problem. Ended up using a pump to recirculate SuperFlush through heater core for about an hour. Suposedly there is a special tool to bleed the heater core, I used a plastic bottle as a funnel on the coolant tank - the trick is to get the coolant level at the tank higher than the heater core while using the bleed hole on the out line at the core. Hope this helps, its nice to have heat again.
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