forget the prestone super cleaner, tide, dawn, pine-sol etc ... read on.
No offense ... but forget the prestone super cleaner, tide, dawn, pine-sol etc ... do use “DRY” 2-part Prestone Heavy Duty Cooling System Cleaner P/N AS100 (GM P/N 12346500) ... read on.
Just Friday, I had email & phone conversation with retired GM cooling systems engineer John Brunner about cooling & flushing late model GM pickup with failed DEX-COOL. John writes, consults & teaches. I realize we're not talking DEX-COOL here ... but the principles involved are much the same ... if not simpler.
Below is a list of the three most commonly available aggressive radiator cleaners/flushes. They are all liquids, all contain primarily water & some citric acid ... BUT are not recommended by GM bulletins because “The diluted cleaners that are available in liquid form are not recommended for this repair.” quote from GM bulletin #99-06-02-012D dated 04/09/2002.
Prestone Super Radiator Cleaner (1 liquid qt) P/N AS101
Prestone Super Flush (22 liquid oz) P/N AS107
Radiator Specialties/Gunk/SolderSeal Super HD Radiator Cleaner (1 liquid qt) P/N C2232
I have MSDS for all three ... I know what's in them & concentrations ... BTW, both prestones are the same ... one is a bigger jug. & No BS ... I've done a tastetest on all 3.
Quite simply, the above three are wimps. The above bulletin & Brunner recommend Prestone Heavy Duty Cooling System Cleaner P/N AS100 (aka AS-100) ... this is a DRY chemical in a discrete 2-part canister; 9 dry oz of Oxalic Acid cleaner and 2 dry oz of Sodium Carbonate neutralizer. This is available at your GM dealer under GM P/N 12346500 ... I bought some Friday a local GM dealer parts room. Albeit many years ago, I’d used this product many times with great success. I’ve searched for it several times recently but could not find it at any parts house and it is NOT listed on Prestone website. This is not a routine warning ... it is a VERY STRONG ACID and can be quite hazardous if not handled carefully ... Perhaps that is exactly why it is not readily available to an increasingly litigious consumer base. I personally was mistaken in that I’d surmised that oxalic acid was too strong an oxidizer for use with aluminum radiator, head, water pump etc. Again, I was apparently mistaken because the AS100 canister reads “Harmless to aluminum cooling system metals and parts when used according to directions” ... AND ... GM bulletin #99-06-02-012D dated 04/09/2002 (and earlier revisions) specifically addresses vehicles with aluminum radiators & aluminum-lined heater cores filled w/DEX-COOL such as my 97 4.3 V6 Sonoma has.
Bottom line for flushing? ... don’t fuss with those wimpy liquids on shelves at most parts houses & wally world. Get the “DRY” 2-part Prestone Heavy Duty Cooling System Cleaner P/N AS100 (GM P/N 12346500) ... cost about $6 ... only a dollar or two more than ineffective liquids. Follow the directions exactly & use extra safety precautions (goggles are essential). And replace your radiator cap with a new one of USA manufacture ... Stant is a good choice. Also, GM bulletin #99-06-02-012D is a VERY complete procedure on how to properly flush ... there may be others that more closely address your needs ... just go to your GM dealer service dept & ask ... mine printed it off for free.
BTW, I have it on very good authority just what the problem is with DEX-COOL. There is NOT a problem with DEX-COOL itself. It works VERY well so long as there is NO air in the system. Its composition makes it much more reactive when exposed to air than the green stuff is. It seems the problem often begins when GM dealers fail to properly topoff-fill during new vehicle prep & check. The air combines with the DEX-COOL and quickly (20,000 miles or less) oxidizes/reacts with metals and forms a rusty goopy mess on radiator cap & neck that disables the radiator caps ability to let coolant back into system from the overflow tank ... more & more air is introduced as a result ... more rust & goop forms and can completely clog a rad or core in as little as 20,000 miles. Since I don’t want to be married to a coolant that can’t stand a bit of air now & then ... and $10 of green stuff/2 yrs is cheap ... I’m gonna flush w/ dry AS100 & refill w/ green stuff.
JACK:gap