flushing cooling system
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Racer
Joined: Jul 2005
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flushing cooling system
Having problems flushing the system on my c4 thoughly,I drained the the radiator,fulled it up with distil water, burp it with the car running,ran for ten mimutes with the heater on, temp was fine,shut her down,let it cool for a few hours,drained it again,still green antifreeze coming out,a little lighter in color but still green.I did this three times already still old antifreeze in there,now it started to over heat,what Im I doing wrong?any Ideas would be greatly appreciated
Instructor
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From: I celebrate their entire catalog
Many months ago I read a post that said it took the guy 7 cycles of draining, filling, running, draining. If true, you're almost halfway there!
You could pull the knock sensors which will really empty out your block and get all that "hidden" coolant. But since you're halfway there with the fill/drain technique, maybe it's not worth changing tactics. Tough call.
Not sure about why you're overheating except sometimes the burping has to be done multiple times. Last time I did a drain I had to burp it 4 times over the span of 30 minutes.
You could pull the knock sensors which will really empty out your block and get all that "hidden" coolant. But since you're halfway there with the fill/drain technique, maybe it's not worth changing tactics. Tough call.
Not sure about why you're overheating except sometimes the burping has to be done multiple times. Last time I did a drain I had to burp it 4 times over the span of 30 minutes.
Melting Slicks
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If you only drained the rad, then you left a lot of coolant in the block and expansion tank. Did you pull out the T-stat before you flushed? If it's still in, pull it out, and do the flush again.
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Racer
Joined: Jul 2005
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No the T-stat still in, I'll pull it tomorrow and let you know how that works thanks
Burning Brakes
Joined: Aug 2010
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From: Manteca Calif
I opened drain on rad until it was empty then put garden hose in rad fill on slow, start your engine, turn on heater and when you see it run clear turn off engine secure drain plug n fill with antifreeze.....
Le Mans Master
Joined: Jan 2003
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From: Santa Maria CA
When refilling park uphill or raise the front of the car up to make the radiator the high point in the system.
Last edited by 86PACER; Nov 14, 2010 at 02:06 AM.
Racer
Joined: Apr 2001
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From: South Haven Michigan
I have a Prestone flush-n-fill kit on my 89 L98 and it works great for flushing out the old coolant. Plus when I am done I raise the heater hose where the valve is at and fill it from there as it is the high point in the system. I also put the front end on jackstands which I think helps eliminate air pockets. I leave my thermostat in and haven't had issues.
Racer
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Burning Brakes
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From: Washington District of Columbia
Many months ago I read a post that said it took the guy 7 cycles of draining, filling, running, draining. If true, you're almost halfway there!
You could pull the knock sensors which will really empty out your block and get all that "hidden" coolant. But since you're halfway there with the fill/drain technique, maybe it's not worth changing tactics. Tough call.
Not sure about why you're overheating except sometimes the burping has to be done multiple times. Last time I did a drain I had to burp it 4 times over the span of 30 minutes.
You could pull the knock sensors which will really empty out your block and get all that "hidden" coolant. But since you're halfway there with the fill/drain technique, maybe it's not worth changing tactics. Tough call.
Not sure about why you're overheating except sometimes the burping has to be done multiple times. Last time I did a drain I had to burp it 4 times over the span of 30 minutes.
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Drifting
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From: Newark, New Jersey
I have a Prestone flush-n-fill kit on my 89 L98 and it works great for flushing out the old coolant. Plus when I am done I raise the heater hose where the valve is at and fill it from there as it is the high point in the system. I also put the front end on jackstands which I think helps eliminate air pockets. I leave my thermostat in and haven't had issues.
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Racer
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Le Mans Master
Joined: Jan 2003
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From: Santa Maria CA
Purge valves on the T-stat housing didn't begin till about '92. All C4's before that had none.
Burning Brakes
Joined: Nov 2009
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From: Olney MD
Flushing coolant
Well, You probably won't do too bad by leaving the tstat in and driving around till it opens and putting the heater on. Then Drain it one last time, ignore the color, and fill it with 50-50 Green antifreeze. I agree with the crowd who says to avoid Dex-cool.
But two or three drain/flush cycles is enough if you do it every 2-3 years.
We're talking about a car here, not a human.
If you want to give it a 'treat' add a bottle of Water-Wetter. It will help keep temps down.
Also, while you're at it, clean the area between your radiator and your AC condenser (or is it the evaporator?). I found a mouse nest in mine.
Good luck!
But two or three drain/flush cycles is enough if you do it every 2-3 years.
We're talking about a car here, not a human.
If you want to give it a 'treat' add a bottle of Water-Wetter. It will help keep temps down.
Also, while you're at it, clean the area between your radiator and your AC condenser (or is it the evaporator?). I found a mouse nest in mine.
Good luck!
Intermediate
Joined: Jan 2006
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From: East Setauket NY
So it was a warm day today and with all the coolant changing going on, I did mine. Changed it until the coolant ran clear filled it with a 50/50 mix of the green stuff. Ran it until tstat opened with heat refilled all with additional 50/50. Now my low coolant light comes on when I start up and goes away after I drive for .5 miles. Check fluid levels are good both cold and warm. Any suggestions?
Le Mans Master
Joined: Jan 2003
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From: Santa Maria CA
So it was a warm day today and with all the coolant changing going on, I did mine. Changed it until the coolant ran clear filled it with a 50/50 mix of the green stuff. Ran it until tstat opened with heat refilled all with additional 50/50. Now my low coolant light comes on when I start up and goes away after I drive for .5 miles. Check fluid levels are good both cold and warm. Any suggestions?
You need to pack the radiator over the course of the next few days. You still have an air in the system so when you're driving the coolant level drops below the level of the sensor on the radiator and illuminating the light sporadically.
To pack the radiator means to top off with the engine RPM's held at about 1500 or so. Raising the RPM's drops the level in the radiator after the stat has opened. Put the cap back on before letting the RPM's back down. If you have a pre '92 which has no purge valve it helps to park uphill or raise the front of the car with a jack to make the radiator the high point in the system. Also have the heater on full hot and running during this so the heater core circuit is open and everything is fully circulating.
Last edited by 86PACER; Nov 14, 2010 at 09:34 PM.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
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From: Santa Maria CA
If you don't want to do it that way you can also just keep topping it off cold first thing in the morning over the course of the next several days till you can't add anymore. Of course you actually have to drive the car during the day though to help purge out the air.
Last edited by 86PACER; Nov 15, 2010 at 04:24 AM.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
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From: Santa Maria CA
They are different. Dex-Cool is garbage and doesn't belong in these cars. This is a lower intake manifold gasket I replaced not too long ago on a Chevy minivan with Dex-Cool in it. All that orange gunk is from Dex-Cool. That is what I find over and over inside most of the Dex-Cool vehicles I've worked on. Even cars just a few years old. I never see this on green coolant cars. On this car I had to toss out the radiator and cap as well as the T-stat and water pump. GM has been sued over Dex-Cool countless times and shops see this every day.
Stick with green coolant mixed 50/50 with distilled water. I like Peak.
Stick with green coolant mixed 50/50 with distilled water. I like Peak.
Last edited by 86PACER; Nov 15, 2010 at 04:34 AM.