Weird expanding noise under glovebox

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MouthForWar

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Yeah if it's like a gurgling noise
It could be a failing heater core
Also check coolant level could be air in the cooling system

Don't mean to jack the thread, but I have this issue once in a while when I hit the throttle (in gear).

No coolant fumes or leak yet, so the core hasn't completely failed yet I guess. Lol. Also, there's no particular bleed procedure on my truck; it's largely self-venting from what I understand? Not sure how air would get/stay in the system (there's no other leaks anywhere else that I'm aware of either).

My coolant was particularly nasty though, some oil and sludge and the PO hadn't done a drain or flush. I just took care of that when I did the intake mani. Meh.

As far as the OP goes...pretty sure you're just hearing the recirc. door. Mine does that too.
 

Brother Al

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It was said by several and Ill add my own...

If it sounds like a brief 2-3 seconds of something "groaning" with a sorta rubbing/sucking sound, yup Recirc Door groan...

Gurgling is always Antifreeze vs Air in the heater core/cooling system in any vehicle... either a system leak or air pocket.

All SBCs can have air pockets, regardless of what they are in. The heater core in these trucks can definately form an air bubble pocket that doesnt simply flow out, because the heater core is partially above the top of the radiator. Easiest way to clear it is to park it on a hill or put it on jackstands, so that the nose/radiator is higher up than the dash and bleed it.

- Run it up to operating temp on the highway, then Park it on a suitable hillside/jackstands and jam the Ebrake pedal nice and tight. You need the top of the radiator to be higher than the heater core. Shut it down and let it cool off for at least an hour, allowing everything to cool, contract, & depressurize.

Before you start, make sure the radiator is warm, not hot to the touch, if otherwise, give it more time to cool off. Open the radiator cap SLOWLY, to fully depressurize the system. Be absolutely sure you open it very slowly... you dont want to have an antifreeze volcano and get 3rd degree burns... be prepared to close it fast.

Completely open the rad cap, but leave it sitting on the radiator's cap hole kinda ****-eyed to prevent AF from splashing all over. Fire up the truck and let it run for about 30 seconds, then shut it off. Top off the antifreeze in the radiator and run it for another 30 seconds... top off and repeat until you cant put anymore AF into the radiator. Lock the radiator cap down and take the truck for a good run... repeat if necessary... but it should clear itself of any remaining air. Also top off the AF overflow tank to the proper height because if its empty, it will suck air into the cooling system .
 

MouthForWar

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Man, I didn't even think about that (elevating the front end when doing the fill/top off). Makes sense. I'll do that when I've got this thing put back together. Maybe that'll take care of it. Thanks!
 

REALFUNCO

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My 94 sounds like a ticking noise when i shut off the ignition. i call it a time bomb.
 

MouthForWar

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No Problem! Glad to help. Post up how you made out.

Finally got the rest of it put back together and was able to finish bleeding/topping off following your procedure. No air pockets in the core anymore as far as I can tell. We'll see, but I did notice a bit of air being purged during the process, and I haven't heard a peep since, so hopefully we got it. Thanks again!
 
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