Cooling System Cleaners?

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1,909
Location
Tracy, CA
I'm getting to the end of the +15 hour RMI-25 cleaning cycle in the Lumina. I noticed that the filler neck of the radiator has a nice coating of oily/greasy brown stuff that is not water soluble. I'm sure this stuff is only in the filler neck/side tank and in the plastic coolant recovery bottle. I had to change the water pump a few days ago and the aluminum timing chain cover/water pump housing was spotless when I removed the old pump. I want to run a cleaner before starting with fresh coolant and water but opinions here regarding cleaners run the gamut from Preston flush, Prestone cleaner, Prestone flush+cleaner, Cascade, Simple Green, CLR, acid based stuff, etc. I'm thinking just use simple Prestone flush+cleaner (I don't think they make separate flushes and cleaners anymore). Basically, start with the least harsh chemical and go from there. BTW, I'm also not concerned with the intake gaskets. They're not OEM and this car did not have Dex-Cool as factory fill.
 

JHZR2

Staff member
Messages
46,295
Location
New Jersey
Run a citric acid flush. Mercedes shop manuals and a lot of the diesel pages show exactly how to do it. Check diesel giant.
 
Messages
518
Location
Severna Park, MD
The old Prestone Heavy Duty Cooling System Cleaner (no longer available) was very effective and used oxalic acid as the active ingredient. Oxalic acid removes rust. Since the Prestone product is no longer available, here's an alternative flushing technique that works well: Needed: Dry Oxalic Acid (DAP Wood Bleach), dry Sodium Carbonate (Arm & Hammer Super Washing Soda), water To use: Drain and flush the system to remove old coolant Fill it with clean water and add 9 oz of wood bleach powder Run it for an hour or longer and make sure the engine is up to operating temperature Drain the wood bleach solution, repeat if your system is really dirty When clean, flush the system again with clean water and add two oz of the washing soda Run for another hour, drain and flush well. The washing soda neutralizes any remaining oxalic acid. It's not a bad idea to use distilled or deionized water. Add new coolant of your choice
 
Messages
1,438
Location
NY
I have done the citric acid flush on my chevy and mercedes. It works wonders. Just remember to flush out the system with dish washing detergent first so the citric acid can do its job. I get my citric acid off of ebay. Its $14 for 5lbs.
 
Messages
2,824
Location
NYC
Originally Posted By: Olas
A dishwasher tablet works just fine, plus you already have them. No need to go shopping or spending money, just go to the laundry.
That doesn't work anymore It used to work, but the EPA pulled phosphates out of detergents, rendering it too weak for a dirty cooling system.
 
Messages
56
Location
WA
With RMI - 25 in the system for 15 hours, the radiator should be clean down to the base materials. Just do a through water flush, add appropriate coolant product along with 8 oz. dose of RMI - 25; now and every 15k miles thereafter.
 

paulo57509

Thread starter
Messages
1,909
Location
Tracy, CA
Originally Posted By: PHANI1
With RMI - 25 in the system for 15 hours, the radiator should be clean down to the base materials. Just do a through water flush, add appropriate coolant product along with 8 oz. dose of RMI - 25; now and every 15k miles thereafter.
Originally Posted By: paulo57509
I'm getting to the end of the +15 hour RMI-25 cleaning cycle in the Lumina. I noticed that the filler neck of the radiator has a nice coating of oily/greasy brown stuff that is not water soluble.
All, thanks for the input. I'm just going to start with Prestone cleaner/flush or whatever they call it now and go from there.
 
Messages
257
Location
Oklahoma
Originally Posted By: Joel_MD
The old Prestone Heavy Duty Cooling System Cleaner (no longer available) was very effective and used oxalic acid as the active ingredient. Oxalic acid removes rust. Since the Prestone product is no longer available, here's an alternative flushing technique that works well: Needed: Dry Oxalic Acid (DAP Wood Bleach), dry Sodium Carbonate (Arm & Hammer Super Washing Soda), water To use: Drain and flush the system to remove old coolant Fill it with clean water and add 9 oz of wood bleach powder Run it for an hour or longer and make sure the engine is up to operating temperature Drain the wood bleach solution, repeat if your system is really dirty When clean, flush the system again with clean water and add two oz of the washing soda Run for another hour, drain and flush well. The washing soda neutralizes any remaining oxalic acid. It's not a bad idea to use distilled or deionized water. Add new coolant of your choice
Would DAP be ok for a brass soldered together radiator? Being acidic obviously? slomo
 
Messages
518
Location
Severna Park, MD
Originally Posted By: slomo
Originally Posted By: Joel_MD
The old Prestone Heavy Duty Cooling System Cleaner (no longer available) was very effective and used oxalic acid as the active ingredient. Oxalic acid removes rust. Since the Prestone product is no longer available, here's an alternative flushing technique that works well: Needed: Dry Oxalic Acid (DAP Wood Bleach), dry Sodium Carbonate (Arm & Hammer Super Washing Soda), water To use: Drain and flush the system to remove old coolant Fill it with clean water and add 9 oz of wood bleach powder Run it for an hour or longer and make sure the engine is up to operating temperature Drain the wood bleach solution, repeat if your system is really dirty When clean, flush the system again with clean water and add two oz of the washing soda Run for another hour, drain and flush well. The washing soda neutralizes any remaining oxalic acid. It's not a bad idea to use distilled or deionized water. Add new coolant of your choice
Would DAP be ok for a brass soldered together radiator? Being acidic obviously? slomo
In the old days (1980s and earlier) it seemed that most radiators were brass. The old Prestone cooling system cleaner was made with oxalic acid, so I think you would be fine using the wood bleach as an alternative with a brass radiator.
 
Messages
2,021
Location
CA
"In the old days (1980s and earlier) it seemed that most radiators were brass." Actually, more likely they were copper. Copper has superior heat transfer, but it's heavier and more $$, much more. CLR works well, but don't use too much - a cup or 2 is plenty. A generic like ZEP brand is fine and much less $$.
 
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Messages
6,765
Location
Fort Lauderdale, FL
Most were both. I believe it's an alloy of both combined. I've seen enough myterious water pump failures soon after dishwasher detergent flushes to recommend against them. SHOUT is the recommended treatment before using a citric acid flush, and seems to work well without causing damage. About to do this to my Jeep and install a coolant filter to catch anything remaining that might be flying around.
 
Messages
247
Location
SE
After observing a couple of plugged radiator tubes through thee radiator cap hole, I am thinking about preforming oxalic acid ( or CLR / ZEP equiv, citric acid, sulphamic acid ) flush on my 1994 Ford 7.3 IDI ( brass radiator (copper ?) , cast iron block, colling system capacity 8 gal) However, I am concerned that larger loosened large particles might clog up the coolant passage in the engine oil cool located on the lower part of the engine on the driver's side (no east to R/R with engine in vehicle). Any suggestions ( besides flushing radiator, heater core, and engine separately) ? I if I use citric acid , wht is the dose per gallon of water in the system ?
 
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