92 Caprice Heater Core Problem SOLVED!!!

About a year ago I posted some messages concerning a 92 Caprice that I had replaced the heater core in and it lasted only 30 days or so before leaking
again. Got a replacement, same story, 30 days to the day and it sprung a leak as well.
Got number 3 and same story so this time I tossed in some stop leak and have lived with it over the summer, but now it is winter and while the stop leak fixes the holes as soon as they occur, I have to do something.
I went down the electrolysis path, defective unit, installation problems (meaning I was breaking them) and so forth and never got anywhere until...........
I had replaced the factory hoses which have those quick disconnect connectors, are bent like pretzels and consist of a metal and rubber mess, with normal heater hose because they cost over $100 for both of them and only GM makes them.
That was the mistake that killed me.
Turns out, the factory hoses have a check valve and a restricter in them which limits the flow, and back flow through the heater core.
Obviously my replacements did not, and if you look at the factory hoses you will not see these valves as the hose is encased in aluminum , plastic, rubber and that coiled protective sleave stuff they wrap wiring harnesses in.
The FSM is completely wrong as well because the pictures show an external valve, yet the description says the valve was eliminated for 1992. Even the parts guy at GM was confused!!
FWIW, I got the new hoses, a new heater core and all is well!!!
Hope this helps another poor soul who may think about the same thing.
psycho.
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psycho,
Interesting. But I wonder why the old-fashioned hoses caused a problem. Why are flow and backflow restricors needed?
BTW, how hard ws it to replace the cores ?
I am thibnking of buying a 90's Caprice, and wonder about how easy they are to work on. I can't seem to find them for sale anywhere !
L Thanks
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On 19 Sep 2003 23:22:22 GMT, snipped-for-privacy@aol.com (Lecher9000) wrote:

For the life of me I can't figure it out. It doesn't make sense to me, but it definitely will pop the core if straight hose is used.
According to the description in the FSM, their is always water passing through the heater core even if the heat is not turned on, unlike previous models that used that little vacuum activated valve in line with the supply line. The one that would leak all the time.
The supply hose comes out of the manifold, through the valves, into the core and out through another hose (which doesn't appear to have any valves) and to the radiator.

Not too bad. A plastic baffle box on the passenger side comes off with a few screws and the core is right there next to the evaporator.
Several of the screws are right up against the floor at the firewall (the book even mentions this) and are a bit tough to get out, but not too bad.
At least the dashboard doesn't have to be dismantled!

That's the square model I believe. They are all pretty easy cars to work on and parts are cheap and usually easy to find.
psycho

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