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Old 10-12-2002, 11:54 PM   #1
frisky68
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heater question

when i purchased my 69 the previous owner had installed a new heater core....my question is the cores outlets are 5/8 and 3/4......the 5/8 is on top..w/ the heater hose running from it to the intake manifold outlet...the 3/4 outlet is running to the water pump..vehicle does not have a heater valve on it...my problem is that i am getting very little warm air @ best from it...from some other engine pic posts ive seen it looks like either the heater core is in upside down or is plumbed wrong...but the correct hoses are running to the correctly sized outlets..the posts that i have seen show the5/8 hose on the bottom of the heater core and the 3/4 on top.....any ideas or suggestions..as it is starting to cool off here in Northern Indiana....thanks............Ken
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Old 10-13-2002, 12:03 AM   #2
Longhorn Man
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While one way or the other is right, either way will work.
I think your trouble lies in the heater box its self. My money says you have all kinds of leaves and ca-ca blocking the damper door preventing a good tight seal. That or rotted rubber on the damper door.
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Old 10-13-2002, 12:08 AM   #3
Zkast
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With or without A/C, in either case the upper hose is your return (waterpump fitting)

A quick test is to bring the water temp up to normal. Check the inlet hose (from intake) is it hot? should be... Next check the outlet hose (to waterpump) is it warm? Is it Hot? or is it cold.

If its hot, your not drawing air across the heater core (check blend door). If its cold you have a restriction in the water flow (heater core/waterpump/intake)

Check for crimped heater core pipes, check for good flow coming from the 5/8's hose (from the intake).
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Old 10-13-2002, 03:44 AM   #4
oleblue72
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My heater core, damper and all was packed full of leaves and other foreign material. I had to replace the core and after a good cleaning it made a huge difference in the heat output.

Good Luck
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Old 10-13-2002, 08:32 AM   #5
Alaskan
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Coupla more things to check is the engine thermostat, it's easy if you have a good manuel gauge. Also the dampener door cable might be broke or sticking. But more than likely it's twigs, leaves, dead bugs or bad gaskets like others have said.
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Old 10-13-2002, 09:40 AM   #6
frisky68
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addl. information

I have the blower fan hooked to a toggle switch b/c the heater switch is bad..this switch only runs the blower motor, correct ??
for low speed and hi speed fan...also the temp lever is stuck fwd...which should be set for heat...will not move back...so it probably is full of 33 years of garbage, will check that out today.
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Old 10-13-2002, 10:08 AM   #7
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I'll double check but I beleive if the cable(door) is pulled inward towards the inside of the cab, thats full heat. Away is closing off the heater core passthrough. Check this at the heater duct housing inside the cab. The cable passes through on the passenger side and is pretty easy to see.
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