Stop Leak In Radiator

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Jimbarry

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The heater core seems to be plugged up after replacing the intake manifold. The truck had stop leak in it when I bought it and I added some to get it home due to a leak at the heater hose inlet. I'm going to try to back flush but has anyone successfully gotten stop leak out of a heater core and, did you use anything but water?
 

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Ok, water it is!!
 

idahovette

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If you have a way to hook a hose to a hot water tap that may help loosening that stuff up??!!! Try it a few times alternating the flow.
 

Jimbarry

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If you have a way to hook a hose to a hot water tap that may help loosening that stuff up??!!! Try it a few times alternating the flow.
Thanks. It isn't possible, too far and not enough hoses. I read online that a 50-50 mix of white vinegar and water loosens calcium but also read that it damages joints and there is no info on stop leak removal. I'm going to go easiest first, drain, remove thermostat, then backflush heater core then entire system to try and get all the residue out. In my experience backflushing hasn't been real successful but it's worth a try.
 

Jimbarry

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Go both directions with the water flow. Maybe that's what you meant my back flushing. It will require some patience... get beer.
Yep, run the pressure both ways. I almost have enough beer i think...
 

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Rusty Nail

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Ever seen a heater core before?
Ever used Stop Leak before?
Ever seen a heater hose before?
Dontcha reckon it's pretty damned tough to "plug up a heater core with stop leak"?


Did I miss something?
:scratchhead:

We need pix.
 

shiftpro

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Ever seen a heater core before?
Ever used Stop Leak before?
Ever seen a heater hose before?
Dontcha reckon it's pretty damned tough to "plug up a heater core with stop leak"?


Did I miss something?
:scratchhead:

We need pix.
You did miss something. You're never seen it happen that's what you missed. It's easy to do, seen it a few times. Even blocking head passages. Not necessarily stopping flow through a head but getting in to the nooks and crannies... which restricts cooling.
 

Jimbarry

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Don't know Rusty, I'll let you know. Do you miss a lot? Once this rain/ snow stops I'll try the flush and see how much stopleak is actually in there.
 

Rusty Nail

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I dunno exactly what SBC cooling system line pressure usually runs but the radiator caps are 16 pounds or so yeah?

I imagine 16psi of water pressure goin through one inch diameter coolant hose at 195°... Good luck with diagnosis!
 

Jimbarry

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I dunno exactly what SBC cooling system line pressure usually runs but the radiator caps are 16 pounds or so yeah?

I imagine 16psi of water pressure goin through one inch diameter coolant hose at 195°... Good luck with diagnosis!
Yeah it's a BBC but probably around that pressure. I was going to put a valve on one end to fluctuate the stream but on 2nd thought I don't think I will. Too much of a chance of over pressurizeing the core.
 

Rusty Nail

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Why don't you undo the top hose and observe the volume ? The bottom hose (of the heater core) is the inlet, yes?
I bet you could save some money (at the expense of time?) using a 5 gallon bucket to see how closely the volume (pressure) of output meets expectations.
 

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