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8th Gen Antagonist
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Discussion Starter #1
This is how to properly bleed the cooling system on your 3400 engine, perhaps you have no heat at idle, or perhaps you just replaced a component, or maybe just a basic drain and fill. Regardless of why, this is what to do.

First, fill the overflow reservoir to the "full hot" line. Next, loosen the bleeder on the water pump outlet, both bleeders are 7mm.

Then fill the radiator till fluid starts coming out of the bleeder, close the bleeder and stop filling. Put the radiator cap back on, and start the car. Turn the heater controls all the way to hot, and let the car warm up to operating temperature. Once warm, open the bleeder screw on the thermostat housing

Once air stops coming out of the bleeder, close it.

Leaving the heat on full, drive the car around the block. You should now be free of any air pockets in the cooling system. Don't forget to recheck the level in the overflow tank.
 

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Back in Black
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Good write up King, maybe make this a sticky
 

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8th Gen Antagonist
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Discussion Starter #3
Already done, and thanks.
 

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Mr. Handy
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Can you still purge the air out when you break the bleeder on the pump?
Yes you can

Replace the bleeder or ..

1. Fill rad
2. Leave cap off and start car
3. Squeeze upper and lower rad hoses to squeeze out air
4. Let engine warm up
5. Add coolant as necessary
6. Squeeze hoses again and use towel if need be to protect hands
7. Check coolant again and refill, also fill overflow tank to correct line
8. Go for a decent drive and check coolant level once engine cools down


Monitor engine temps during this whole process and leave heater on full blast. You should see via your temp gauge the coolant thermostat open and your temps dropping. If your temps spike your T-stat is either stuck closed or you have a big air bubble yet.

I have done this many times and it has never failed me or have I ever had issues. It's just not worth the risk for me to break the bleeder valve. I'd rather do it the good ole' fashioned way.
 

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8th Gen Antagonist
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Discussion Starter #7
That will also work, just more of a pain.
 

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Mr. Handy
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I drained mine out and refilled without even using the bleeder, just filled it up at the reservoir and the rads cap.

Since the coolant will not be doing any cycling whatsoever before the car warms up, due to the thermostat been closed, usually 180 degrees before it opens, you may be low on fluid, I simply let the car warm up by driving it around, carrying extra water/coolant in a 1 gallon jug. Once the temps reach the middle area, they may go a tiny bit over, turn off and let cool for about 10 minutes or so, then add more fluid, its been keeping me cool for months like that.


However, the bleeder is the right way to do it as it will not require any top offs after the original fill up.
 

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Kingnutin the Genius

Kingnutin, you are my hero.

Long story short, I was ready to trade my 3400 Impala, as I had fought an overheating problem to the point I was disgusted. After reading a lot of BS with people having the same symptoms/problems on various forums and no one with an obvious answer other than people blowing thousands of dollars on unneeded repairs that didn't fix the problem, I found this thread.

Bottom line, I followed your instructions, and my chronic overheating problem was cured.

This forum is bookmarked!!

You da' man, Kingnutin!!
 

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Super Moderator
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Welcome Doctor! Feel free to use this forum whenever necessary! King is pretty cool, eh? Oh, and we can use a doc here sometimes....




Hey King, yer gonna have to grease your ears to get through doorways... :giggle::lol:
 

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8th Gen Antagonist
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Discussion Starter #13
Happy to be of service! I pick up lots of little things along the way with how much I work on these cars, it would be criminal not to share.
 

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Thanks again

Happy to be of service! I pick up lots of little things along the way with how much I work on these cars, it would be criminal not to share.
That is more than a little thing. :clap:

From my I-Net research, I learned this is a very common problem with the 3400, but no one out there seemed to know the right fix (and be it so inexpensive).

I have now driven my car a few hundred miles since properly bleeding the system per your instructions, and she runs like a new one now.

Here was my key to finally figuring I must have some kind of circulatory problem, per the way the car was operating prior to the proper bleed....

1) The heater would only work at speeds of 70mph and greater. Let off the gas on the freeway, and cold air instantly blew from the heater. Once I bled the system, hot air returned to being perfectly normal. Evidently, the air lock was within the heater lines/coil? The worse the heater progressively worked, the more often the car would overheat.

To think I went all winter without a heater, and had continuing intermittent overheating problems, was ready to sell my perfectly good and paid for Impala, and all I needed was a proper bleed... Jeez.

I also learned that any engine maintenance, including parts replacement, anti-freeze change, and even in some cases, just taking off the radiator cap, can cause the cooling system to ingest air. Hence why the problem is so common I assume. The bigger problem is, unknowing suckers are paying countless dollars for unneeded repairs. My mechanic suggested we put an intake manifold gasket on. I asked if that would cure the problem. He said, "I can't guarantee that." Needless to say I skipped his suggestion minus a guarantee. I also will find a new mechanic, though I do most of my own work, my job is long hours, and sometimes for routine stuff I will pay to have work done.

Thanks again KingNutin. You made a big difference in my budget. I couldn't afford a car payment. Thanks to you, I don't have to worry about that.
 

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something I would like to add that is in the same general venue. When you change your coolant. Instead of using tap water, use distilled water. Get 3 x 1 gallon jugs, what you have left over use for your battery ( if fillable).
 

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Mr. Handy
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something I would like to add that is in the same general venue. When you change your coolant. Instead of using tap water, use distilled water. Get 3 x 1 gallon jugs, what you have left over use for your battery ( if fillable).
Should always use distilled water. Yet, most people just use tap water whether it be from a well or city water.
 

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8th Gen Antagonist
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Discussion Starter #17
Distilled is ideal, but honestly I have always used tap water, never been an issue for me. Batteries are another story.
 

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What about needing to get the bleeders higher? I've seen many a folk talk about using a no spill funnel at the rad cap, or parking with the front of the car inclined, etc? I have an Alero with the same engine and am needing to bleed it. (I also have an 02 Impala which is why I'm joining this group.)
 

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Super Moderator
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Might see if your local parts store ( auto zone, O'Reillys etc.) has a rental program for tools and see if they have one of these

Uview Airlift 550000 Demonstration, Pressure Test, Coolant Fill - YouTube

I bought one recently and although I have not had the opportunity to use it myself yet, there are a number of videos of people that have used them and swear by them.

Makes sense that if the entire system is under vacuum ( 25+ inches) then no reason to have to bleed it. Coolant should be the only thing in there.

I have an antifreeze change to perform on my Nissan diesel truck sometime before winter. I will give it a try at that time and post my thoughts on it.
 
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