Cooling sytem scale removal

[Warp6]

What's the best method for cleaning the brown sludge from a radiator/cooling system? Please describe steps and/or processes you have tried and are proven.
This is in reference to my wife's vehicle she had before we were married. Someone mixed ethyl glycol in with dexacool and really messed things up. I've flushed several times but I still have the leftover brown crud all over everything. I figured this could prove useful to Buick owners as well.
Also - sorry for putting this in the wrong forum

 

[turbo nasty]

If the stat could be pulled and you could back flush the syatem with a water hose shoved in the return hose from the block to the radiator for starts. Then the heater core needs flushing along with overflow/expansion tank
next the radiator.
I recommend puling the rad when back flushing it as well flush until clea, now if the radiator core is clogged then it should be replaced or serviced.
Once that is done get some RMI 25 and distilled water (t stat replaced at this point if pulled) and drive the car as much as possible and flush the system in 2 weeks.
Then do the above flush procedure again and then refill with rmi and dist h2o and drive for a month or so monitoring the coolant for floating crap or crud in suspension and that should get it cleaned up.
May need to do it one more time in another month.
After that it should be straight.
Just remember your freeze protection in the winter months

 

[jhanson1750]

I ran into the best way as a service manager at a Groendyke transport terminal. Drain all coolant, Flush with clean water, Remove thermostat, refill with water, Cascade dishwashing detergent POWDER NOT LIQUID!!! 1/4 CUP PER GALLON. Start the car and pour the detergent into the radiator. DO NOT INSTALL RADIATOR CAP. Let idle for 4-5 miniutes. Let cool for @ 45 miniutes and drain. Flush with clean water until clear water exits the ratiator. This is how we cleaned the cooling system on Detroit disel engines. I have been doing this on cooling system for years and it works. The detergent is strong enough to cut any scale in the cooling system but does not eat away and soft metals like aluminum,brass or copper. The only time I have found a problem is if there was a hole in something and there is a scale deposit blocking it. When the scale is removed there is a leak. I have had some vehicles that it took 2-3 times but it works great. Jon

 

[JDEstill]

years ago I got a Prestone flush kit. In the kit was a tee that had two barbed hose ends and one threaded garden hose end. The idea was to cut one of the heater hoses, insert this tee, hook up a garden hose, and just let the car idle with the radiator cap off while you pumped fresh water into via the garden hose. Worked pretty good I thought. Just keep it going until the water coming out looks all nice and sparkly. On my GN I didn't cut the heater hose as per the directions, I just took the heater control valve out and replaced it with the tee. Then when done flushing, swapped it right back. Combining this with some kind of radiator flush chemical, or the detergent idea listed above, ought to do the trick.

John

 

[Pablo]

Dexcool will do that all by itself without any outside help.

I highly advise against using it. GM just settled a big class action lawsuit having to do with the problems caused by dexcool.

My 98 olds intrigue was completely full of sludge which ended up contributing to a lot of problems. I flushed about 10 times and then switched to the green stuff and no more problems.