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2004 chevy trailblazer_lt
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Discussion Starter · #1 ·
I will be replacing my t-stat soon. A previous owner has switched the coolant over to the green stuff, and after reading this forum I thought I should switch back over to dexcool. I was wondering if it would be a good idea to flush water from the top radiator hose through the block with the thermostat off to clean out the green stuff. Is there a good way to flush the heater lines out? Is it really worth it or is it ok to use the new prestone that is supposed to go 5 years?
thanks
david
 

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2005 chevy trailblazer_ls
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That would probably get most of it out, but the only way to really get the heater lines would be to drain the system, fill with distilled water, and run it with the heater on high to operating temp. Do that 2 or 3 times until the water coming out is pretty much clear. Then refill 1/2 of the system capacity with undiluted dexcool. It takes a while, but like wooluf said you DO NOT want to mix green & red/orange/pink. Chemical reaction...not good. You may even want to consider a chemical flush or a backflush setup, especially if the previous owner did not get out all of the dexcool before putting in the green stuff.

Or, you could just stick with the green and change it every year.

The service manual procedure for flushing says to remove the thermostat, drain and fill, then run the engine for 20 minutes, drain, repeat until nearly colorless, install the stat, and fill. Now, call me stupid, but if anyone can figure out how to remove the stat, then not only fill, but run the engine for 20 minutes...I'd love to hear it!! It does not differentiate between the LL8 or LM4 engines in this procedure. Hopefully this is a misprint, but could be a bad one.

Off the subject...I lived for several years in Bassett. Hello to Danville!
 

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Discussion Starter · #4 ·
Maybe I can " remove" the the old thermostat from the housing and use the housing till it's flushed, then replace with new t-stat.
The green prestone you see on the shelf now claims to last 5 years or 150,000 miles. The kind that says you can mix with any color antifreeze.

About Bassett sctb, my wife and I just went up to Pigs R Us the other night. We go up to that area rather often.

david
 

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The service manual procedure for flushing says to remove the thermostat, drain and fill, then run the engine for 20 minutes, drain, repeat until nearly colorless, install the stat, and fill. Now, call me stupid, but if anyone can figure out how to remove the stat, then not only fill, but run the engine for 20 minutes...I'd love to hear it!!
When you get the t-stat and housing out, grab the housing in both hands. Push down hard on a flat surface and twist the housing about 1/6 turn and release the pressure on the stat spring. You now have the four pieces, bottom keeper, spring, t-stat, and housing. Assemble in the reverse order. :cool:
 

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When you get the t-stat and housing out, grab the housing in both hands. Push down hard on a flat surface and twist the housing about 1/6 turn and release the pressure on the stat spring. You now have the four pieces, bottom keeper, spring, t-stat, and housing. Assemble in the reverse order. :cool:
Well, I'll be...live and learn!! Thanks :thumbsup:
 

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Maybe I can " remove" the the old thermostat from the housing and use the housing till it's flushed, then replace with new t-stat.
The green prestone you see on the shelf now claims to last 5 years or 150,000 miles. The kind that says you can mix with any color antifreeze.

About Bassett sctb, my wife and I just went up to Pigs R Us the other night. We go up to that area rather often.

david
There are several companies now making coolant that can install after Dex-Cool, and likely work better. I've made the switch myself, as I've found that Dex-Cool vehicles typically have a lot of problems as they age -- things like leaking radiators, heater cores, and even engine castings -- all eaten up by the acid build up in the "lifetime" coolant.
 

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2007 chevy trailblazer_ls
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Something to add to your vehicle check is a simple "litmus paper" check. Simply dip the tip in you radiator fluid and it will measure the amount of acidity in you coolant. The company I work for does this on every "P.M." check (500 hour oil change) to moniter the fluids acidity. I've never been able to leave the fluid in for the five years they say it will last but then again show me a warranty that last longer than five years. The dealer wants your engine to fail or leak after it expires.:m2:
 

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2003 chevy trailblazer_ls
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Something to add to your vehicle check is a simple "litmus paper" check. Simply dip the tip in you radiator fluid and it will measure the amount of acidity in you coolant. The company I work for does this on every "P.M." check (500 hour oil change) to moniter the fluids acidity. I've never been able to leave the fluid in for the five years they say it will last but then again show me a warranty that last longer than five years. The dealer wants your engine to fail or leak after it expires.:m2:
I've seen the problem in other ways... As a Snap On dealer, I got to call on over 100 shops and dealerships. There was almost always a Chevrolet vehicle in at least one bay with cooling system problems -- usually a head replacement, at times, a complete cooling system replacement, heater core, radiatior, all lines, water pump, etc. All looked fine from the exterior, but inside were completely eaten away. You could poke your finger through the coolant passages on some heads, they were so thin...

The independents called Dex-Cool their "bread and butter." It ranked right up there with Ford's rack and pinion issues, and electrica and door hardware problems on Dodge/Chrysler vehicles.
 

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Discussion Starter · #10 ·
So what should the acidity read in coolant? I believe the blower motor was replaced in my TB before I bought it at around 80K miles based on receipts I found in the glove box. Would they have had to drain coolant to do this?

thanks for the great replies!
David
 
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