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1997 Blazer heater core

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08-04-03, 06:30 PM   #1  
1997 Blazer heater core

I have a 1997 Chevy blazer 4.3L V6 with 140,000. The heater core seems to make gargoling sounds when you are taking off. Does anyone know an easy way to repair this problem without changing the heater core.

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knuckles's Avatar
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08-04-03, 07:36 PM   #2  

First, make sure the noise you're hearing is actually coming from the heater core. A clogged a/c evaporator drain will cause water to pool in the evaporator case. This causes a sloshing sound when accelerating or making turns.

If you're sure the noise is coming from the heater core, you can try backflushing it. You can buy a Prestone kit to backflush your entire cooling system (recommended) or you can simply use a garden hose directly on the heater hoses.

Clogged heater cores are pretty common on these trucks. The problem is the coolant. Dexcool, despite all claims to the contrary, DOES NOT LAST 5 years or 100K miles without suffering from age related breakdown. Solids precipitate out of the coolant and clog the heater core.

After flushing your heater core, flush the entire system and refill with a 50/50 mix of DexCool and clean water.

From now on, flush your cooling system and replace the coolant every 2-3 years or 30K miles.

darrell McCoy's Avatar
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08-04-03, 07:37 PM   #3  
darrell McCoy
Noise is usually a sign of low coolant or an air lock in the system.Have you ever flushed the system and changed the coolant?

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08-04-03, 08:15 PM   #4  
I agree with both the other gentlmen..Low coolant will definately cause this noise..And because those engines are prone to this other problem, pressure test the cooling system. Look for leaks at the intake manifold..(this will definately cause the low coolant condition/gurgling noise in the heater core..) They'll usually leak driver's side front corner of the intake, or passanger side rear corner...

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08-04-03, 11:54 PM   #5  
There is a class action lawsuit againt GM now due to DEXCOOL antifreeze. Check it out at www.classactionamerica.com

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08-05-03, 03:36 AM   #6  

All GM will do is say, "Well now it's no longer extended drain". LOL.

That is the true problem, people think they don't have to change their coolant regularly.

Newsflash: You do . I do mine every year. At the same time, I inspect the cooling system parts and look for any troubles. This is how you avoid breakdowns .

I agree with Knuckles.

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