flushing cooling system - Chevy Impala SS Forum
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post #1 of 7 (permalink) Old 10-04-2016, 07:02 PM Thread Starter
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flushing cooling system

when flushing cooling system should you use just water or can you use a cleaner like prestone radiator flush. According to prestone you should run the vehicle with product and water for 10 minutes at operating temp with heat on then drain and repeat with water. The prestone flush is non acidic. Is this the way to go or plain water?. By the way what should be used to rinse the surge tank?.
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post #2 of 7 (permalink) Old 10-04-2016, 09:08 PM
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Different Century - Different Answers

In the 'Old Days' (long before ingredient disclosure laws) I heard Prestone Flush was simply powdered Oxalic acid (teak wood cleaner), neutralizer (baking soda) and a fancy yellow plastic tee with cap you cut into the heater line and left permanently installed (hoped for at least by Prestone) with successive applications of the same $3.49 price of the total kit price. Yes, I bought it and used it like everyone else back then. It seemed to work, but everyone drained their AF into the stormdrain every year or two when we didn't know it killed dogs and 2 gallons only set you back a whole $3.50 including tax.

Regulations what they are today you're likely getting some (as you say) 'non-acidic' non-phosphate version of TSP - and of course baking soda afterward. I recommend doing a dItpot full of search and "just use your best judgement, Joel."

The surge tank is just a big plastic bottle. Unbolt it from the car and clean the living vrap out of it with whatever you want. Muriatic Acid (aka pool acid, soldering flux....), or magic purple, Bleche-White, TopJob, CLR....

Methodical flush process and burping the system for air is equally important to simply getting the old rotten acidified garbage out of your engine and radiator every 5-10 years.

\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
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post #3 of 7 (permalink) Old 10-04-2016, 11:42 PM
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Good post above. Whatever you do, pull both knock sensors or all your work is for naught.

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post #4 of 7 (permalink) Old 10-05-2016, 06:09 AM
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No Chemicals for me except to flush the Reservoir but this is ONLY after the reservoir is removed from the car first. The Coolant reservoir is a little more difficult to clean completely due to all the passages molded into the tank. Other items like the Block, Rad and Heater core are flushed with straight water to get the "sediment" out of those areas.

I use the KS's to plug the Block holes to fill the block numerous times with water and then remove them again to aid in the "flushing effect" of the block. Do this a few times til the water comes out clear. On the Heater core, I use the Heater hoses that are still attached at the Firewall to both Fill and flush (both ways) numerous times....again unit the water is clear. Then I'll take some compressed air at a very low PSI (20 PSI or so) setting and "Blow out" the water from the HC.

Same with the Rad, leaving the Top Hose connected, fill the rad to the Top, open up the valve and/or pull off the Bottom hose (That I also Plug to retain water) so that the water flushes through a few times. The more volume of water you can get to dump out at once, the greater the flushing effect on each component.

Lastly, since you will be moving these hoses around quite a bit, I would recommend you get a new Flow restrictor and Coolant tee. these get brittle with age and heat cycles and once you move those hoses, they can become compromised and break....at the worst time. Ask me how I know this. I went with a tee that was made from metal instead of the plastic and just got the AC Delco Restrictor. New T-Stat and oring gasket are a good idea too along with a new pressure cap on the reservoir. Fill with a 50/50 mix of coolant and Distilled water and should take 2 gallons of each on a bone dry system. GL

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post #5 of 7 (permalink) Old 10-05-2016, 08:03 AM
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back when I like everyone else used tap water and silicate antifreeze in 1980 and older vehicles with lead soldered radiators did have to use the 2 part acid/neutralizer flush procedure. GM V8 engines had the drain plugs on each side of the block.

drain out all the anti freeze . mix up the acid. fill the coolant system adding the pre mixed acid run it for an hour or so do some driving. then dump it out and using a water hose flush out all the scale deposits . then add the pre mixed neutralizer to the coolant system and let it idle for 15 min or so and dump that out . block /radiator very clean then 2 years later you get the same scale issue with the coolant/tap water used. [poor cooling]..

I changed the water used back in the late 1980's . never had to use the acid again. only distilled water with 65% antifreeze.. my 96 coolant system is very clean and no corrosion .. when I take the goose neck off the metal is not corroded in any way/no deposits. 3-4 yrs on the coolant change. no acid required DEXCOOL.

I still have that acid kit ..I doubt I will ever have to use it with how I do this since 1980's.

If someone does screw up and mixes different antifreeze , then the acid will be required ..
I also only use the same manufacturer on anti freeze as well as the spec.
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post #6 of 7 (permalink) Old 10-06-2016, 05:29 PM
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Btw - if my last post doesn't explain the flushing process/steps real well, do a Search here as there are many threads that will help guide you in doing this correctly.

As for chemicals, I just never used them or personally believed in them very much. Newer Componet materials of modern engines and cooling system parts (aluminum/plastic vs old school copper/metal rads for example) is another reason for this. Not to mention the whole neutralizing process after being sure you completely flush the flush chemicals is another reason. Just my $.02.

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post #7 of 7 (permalink) Old 10-06-2016, 06:23 PM
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I flushed my cars cooling system a number of times because it had mud for coolant, and it never really cleaned up, so I decided to actually take it apart and clean it.

Now this is opinion, but it went so much better once I removed the reservoir and backflushed everything. The reservoir was holding a couple pounds worth of mud/rust in its little chambers that I got out by filling it then aggresively shaking it as it emptied. That was the only way to get the sediment to come out. I flushed the reservoir about 8 or 9 times just to get clean water to come out of it as I shook it. That covers the reservoir.

As for the rest of the system, I bought one of those stepped garden hose backflushing tools and that was the best 35 dollars I spent. I could flush my car in a matter of a minute with that thing. And you simply go from hose to hose and it collects all the crap and pushes out. As for the restrictor and Tee, you have to replace those. Mine broke after I put the old ones back in with new hoses and thankfully, I had the hood open as I was filling the tranny when it decided to break. so I just hurried and shut the car off. of course it pumped about a gallon of coolant out in the 15 seconds it was broken, but hey, I caught it in my driveway. So I put a new restrictor on. Its a 7 dollar part on rockauto, I think.

I made a coolant filter for my car from a baldwin filter head off amazon and napa filters. Never flush again, except to change old broken down coolant. I cant recommend to anyone with one of these cars enough to get a coolant filter. Thankfully space is plentiful under the hood so adding it is as simple as a splice and hose clamps. I can post up what I bought if anyone is interested...

94 RMSB 170K Sat 5 years, ran for 1 of those then remained untouched for 4. Sat because it was slapped by a deer and the owners didnt want to fix it for whatever reason.
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