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Discussion Starter · #1 ·
My car is not a daily driver; just under 24K miles but the heater core is out...again. This will be the 2nd one I have replaced. Testing the coolant shows now AC voltage so I assume there is no electrolysis going on. I have a head cooling mod and am running the outer plastic restrictor without the inner washer. I have read the TSB regarding this issure and I can only assume that since there is no AC voltage present, I either have a flow/pressure issue or I'm just the unluckiest guy in the world and got 2 bad heater cores (the original from the factory and then the one I just replaced 8K miles ago). Anyway, I researched this issue first time around and here I go again. Can anyone shed some light on what I need to look for this time around or what exactly the problem is? Heater core R&R ain't exactly a fun thing to spend a Saturday afternoon doing...over and over. Thanks for any help.

Jeff
 

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Why not replicate the factory restictor somehow? I've also read that nearly all of the replacement heater cores are junk. Did you put a Ford part in there or a generic parts store replacement?
 

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Why not replicate the factory restictor somehow? I've also read that nearly all of the replacement heater cores are junk. Did you put a Ford part in there or a generic parts store replacement?
I replaced it the first time with an OEM core. I talked to a radiator shop and they said most your OEM stuff comes from over seas; replace it with a Detroit this time around as they are made in the U.S. and are clearly a better product. And as far as the restrictor, it was the factory restrictor, just minus the 3/16" inner washer. There is just so much debate as to what restrictor to use when running a cooling mod (none at all, outside plastic only or the outside plastic plus the inner washer). I could be wrong, but it would make sense to me that taking the restictor out altogether would decrease pressure inside the core. It would be no different than putting a restrictor on a running water hose; there would be an increase in pressure and a decrease in volume. Who knows though.
 

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The restricter acts as more of pulsation dampner. The coolant flows in pulses and the restrictor helps to soften those pulses before they enter the core. Second, did you put foam on the outer portion of the core before placing it in the heater box? If you just put it in there with no foam insulation, I have seen it where it will leak because of it being able to vibrate against the heater case.
 

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Ford put it there for a reason. I doubt they just found some restrictor lying around with the same O.D. as the I.D. of the hose and thought, "hmmm, maybe we'll just put this right here...."

I can't explain it based on volume/pressure, but I know I stuck that thing in there when I did my coolant mod.
 

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Discussion Starter · #8 ·
The restricter acts as more of pulsation dampner. The coolant flows in pulses and the restrictor helps to soften those pulses before they enter the core. Second, did you put foam on the outer portion of the core before placing it in the heater box? If you just put it in there with no foam insulation, I have seen it where it will leak because of it being able to vibrate against the heater case.
When I replace it this time, trust me, I will be paying special attention to everything...certainly including things like this.

Ford put it there for a reason. I doubt they just found some restrictor lying around with the same O.D. as the I.D. of the hose and thought, "hmmm, maybe we'll just put this right here...."

I can't explain it based on volume/pressure, but I know I stuck that thing in there when I did my coolant mod.
Yep, I will be putting in the outer plastic restrictor with the inner washer this time around. And I assume you used both restrictors as well (inner and outer)...and never had a heater core failure...?
 

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Yep, I will be putting in the outer plastic restrictor with the inner washer this time around. And I assume you used both restrictors as well (inner and outer)...and never had a heater core failure...?
Correct.
 

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When I replace it this time, trust me, I will be paying special attention to everything...certainly including things like this.

Yep, I will be putting in the outer plastic restrictor with the inner washer this time around. And I assume you used both restrictors as well (inner and outer)...and never had a heater core failure...?
46Stang is a form Ford Line Mechanic, now working on Beemers. Believe him
 
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