Author Topic: New To this Forum, Bought a 1987 C20..  (Read 4291 times)

Offline JohnnyPopper

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Re: New To this Forum, Bought a 1987 C20..
« Reply #15 on: June 24, 2019, 02:13:49 PM »
Sounds like you have a cooling problem.

Popping sounds usually come from water boiling in the block when it's real hot and your radiator cap is not holding pressure.

The heater core is the closest part of the cooling/circulation system, so you would hear it.

Bypassing it does not mean you've corrected the problem.

Check your cap for a cracked seal or other cooling issues.
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline VileZambonie

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Re: New To this Forum, Bought a 1987 C20..
« Reply #16 on: June 24, 2019, 07:53:49 PM »
Quote
My mechanic say the fix to it is to put in a very small. mabee 1/4 inch size restrictor tube in the heater Hose lines to reduce the amount of flow through the heater core...

I think your best investment is a new mechanic.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Online bd

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Re: New To this Forum, Bought a 1987 C20..
« Reply #17 on: June 24, 2019, 08:02:29 PM »
 ;)
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
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Offline 75gmck25

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Re: New To this Forum, Bought a 1987 C20..
« Reply #18 on: July 05, 2019, 07:30:48 AM »
Other than to resolve a leak, I've never seen a recommendation to bypass a squarebody heater core.  They are usually continuous flow (always have water running through ), so there isn't much of anything to fail except to start leaking.

One very common heater problem is that a lot of junk falls down the defroster vent and ends up in the plenum behind the glove compartment.  If you remove the glove compartment door you can access the screws that hold the panel on the heater plenum right behind the glove compartment.  Then you can see the blend door, move the controls to make sure it goes full travel, and pull out the pens, pencils, matchbooks, parts receipts and other junk that has fallen down there.  You might even find remnants of a mouse nest they made from the fluffy insulation on the firewall.

Bruce