View Full Version : Radiator flushing and engine internal cleaning

Paul Steinberg
04-12-2017, 10:23 PM
What I use is Arm & Hammer Washing Soda (NOT BAKING SODA). You can purchase it in the laundry isle of the supermarket. Drain the entire system by pulling off the lower radiator hose at the radiator. Be careful not to damage the radiator hose nipple, by using a pointed tool designed to loosen the hose without damage to the radiator or the hose. Use of this tool is important, so you don't break the soldered joint. Next, remove the thermostat, and replace the thermostat housing. Then remove, swap, and reinstall the heater hoses on the engine side of the heater hoses. This is important, because you can easily damage the heater core hose nipples, if the rubber is stuck to them. If you need instructions for removing them without breaking them off, let me know. Reinstall the lower heater hose, and clamp lightly. Now you are ready to start cleaning. Dissolve 1 cup of washing soda in a couple quarts of water, and pour it into the radiator. Fill the engine and radiator with clean water, and make sure that the heater valve is closed. Once the engine and radiator are full, start the engine, and at a fast idle, allow the cleaner to work for about 15 - 30 minutes, or until you see it turning a bright orange color. Shut engine off, and carefully pull the lower radiator hose off, allowing the cleaning solution to exit quickly. Allow the engine to cool until you can put your hand on the engine without it being hot. Usually this takes about 1/2 to 1 hour. Reinstall the lower radiator hose, and repeat. Do this until the water is clean and white looking. Then, open the heater valve, and allow the solution to clean the heater core. The reason for reversing the hose connections, at the engine, is so the heater core is flushed backwards, so it doesn't clog. Allow the solution to flow through the heater core for about a half hour. Then pull the lower heater hose one more time. Remove the two heater hoses from the engine, and point one toward the ground, and flush the heater core with fresh water from a hose. Do it in both directions, to make sure that everything in the heater core is removed. Put fresh water into the engine, and run till it is warm to hot. Drain from the lower radiator hose once more. When the engine is cold, I would replace all heater hoses, radiator hoses, and thermostat with new parts. Add pre mixed anti freeze, and you should be good to go for another 3 - 5 years. I prefer the premixed anti freeze, because it is made with mineral free water, and it is also PH balanced. If you are not sure of the engine, it might be wise to check the water pump also. Many times, once you clean everything, they start to leak. The crud in the system acts like a stop leak. The Washing Soda will not cause any harm by itself, but if the engine has years of neglect, you might find that the freeze plugs will also start to leak. If that happens, you might as well replace all of them, because once one goes, the others are not far behind. They are a pain to replace, especially those at the rear of the engine and the rear of the heads. Sometimes, I had to partially remove the engine to get to them all. I have used this method of engine block and radiator cleaning for over 50 years, and have never experienced any problems as a result of the cleaning. I have experienced failures that were a result of neglect. Better to have the cooling system fail now, then later on when you are on the road. The washing soda is a cleaner, that will not attack the metal parts of the engine, only remove rust and scale.

Walter Suiter
04-13-2017, 03:59 PM
My curiosity abounds; Why are you so specific regarding Sodium Carbonate rather than Sodium Bicarbonate?

I only have a few years studying with the master of electroplating rust off an object I want to clean, and truthfully see little difference in performance when using Bicarb with the additional oxygen atom in a water based solution. I've even met people who are addicted to Sodium Pentacarbonate (Oxyclean) as a cleaning agent, who insist more Oxygen atoms increase performance. Magnification of aluminum surfaces in contact with the Pentacarbonate generally shows the aluminum was etched.

By the way, Sodium Carbonate + water + Aluminum becomes a Hydrogen gas generating reaction when heat is added.

Paul Steinberg
04-13-2017, 06:18 PM
From Wikipedia, the free encyclopedia

Sodium carbonate (https://en.wikipedia.org/wiki/Sodium_carbonate)

MSDS (http://www.sciencelab.com/msds.php?msdsId=9927263)

Sodium carbonate (also known as washing soda, soda ash and soda crystals, and in the monohydrate form as crystal carbonate), Na2CO3, is the water-soluble sodium salt of carbonic acid.
It most commonly occurs as a crystalline cecahydrate, which readily effloresces (https://en.wikipedia.org/wiki/Efflorescence) to form a white powder, the monohydrate. Pure sodium carbonate is a white, odorless powder that is hygroscopic (absorbs moisture from the air). It has a strongly alkaline taste, and forms a moderately basic solution in water. Sodium carbonate is well known domestically for its everyday use as a water softener. Historically it was extracted from the ashes of plants growing in sodium-rich soils, such as vegetation from the Middle East, kelp from Scotland and seaweed from Spain. Because the ashes of these sodium-rich plants were noticeably different from ashes of timber (used to create potash), they became known as "soda ash". Sodium Bicarbonate (https://en.wikipedia.org/wiki/Sodium_bicarbonate)

MSDS (http://www.sciencelab.com/msds.php?msdsId=9927258)

Sodium bicarbonate (IUPAC name (https://en.wikipedia.org/wiki/IUPAC_name): sodium hydrogen carbonate) is a chemical compound with the formula Na (https://en.wikipedia.org/wiki/Sodium)HCO3 (https://en.wikipedia.org/wiki/Bicarbonate). It is a salt composed of sodium ions and bicarbonate ions. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate (https://en.wikipedia.org/wiki/Sodium_carbonate)). The natural mineral form is nahcolite. It is a component of the mineral natron and is found dissolved in many mineral springs.Sodium carbonate has a caustic nature while sodium bicarbonate displays less of the sodium carbonate’s characteristics. Of the two base compounds, sodium carbonate is the stronger base while the sodium bicarbonate is the weaker base. The former is diprotic, a term given to something that reacts with two equivalents of acids. After reacting to one equivalent of acid, it then converts to sodium bicarbonate, a monoprotic.
Read more: Difference Between Sodium Carbonate and Sodium Bicarbonate | Difference Between (http://www.differencebetween.net/science/chemistry-science/difference-between-sodium-carbonate-and-sodium-bicarbonate/#ixzz4eAMM7g5z) http://www.differencebetween.net/science/chemistry-science/difference-between-sodium-carbonate-and-sodium-bicarbonate/#ixzz4eAMM7g5z

Walter Suiter
04-22-2017, 03:33 AM
I don't think we're on the same page here when it comes to cleaning cooling systems.
My first problem with your suggested Sodium carbonate or even Bicarb is their etching properties on aluminum radiator tubes. How either soda is derived isn't of much import. My second is their minimal beneficial cleaning properties in this situation. The situation becomes even worse if the radiator has copper tubes.

In the case of a copper cored radiator, your solution actually becomes the electrolyte in a low grade Bagdad or Edison battery. Given that radiators are often isolated from the vehicle ground by the nature of the mounting system or because the radiator wasn't grounded to the frame when installed the situation can become nasty fast. I happen to have some less than joyous experience in short core life from copper radiators back in the 70s. When the tubes were cut open for investigation, pitting was obvious. That situation was determined to be due to the alkilinity of the water in the systems, but I remain hesitant to use an alkiline cleaner.

With an aluminum tubed radiator, either of the Sodas is an etchant commonly used as a precoating adhesion surface prep.

My experience over the years is most cooling systems get flushed only after a problem is discovered, usually black or brown slop showing in the coolant when observed via the radiator neck. Generally the floating black snot is the result of transmission fluid or power steering fluid from a minor leak in one of the coolers that lives in the cooling system. The trick becomes removing this crap from the cooling system without adhering it to cooling surfaces of either the block or radiator core or tanks. The heavy equipment and military vehicle community has developed great fascination for machine dishwashing detergents for this cleaning. I don't particularly care for that approach primarily because the surfactant in dishwashing detergents works well only within the temperature parameters it was designed to. A dishwasher operates with an initial charge of hot water, and flushing a cooling system generally doesn't fall into that design parameter. Add in that the slop has an excellent chance of adhering to the surface you're trying to clean as the coolant is drained and then locks on as cold flushing water is introduced, and you just made the job harder.

Secondly, in my experience, what's inside a car radiator, and diminishing cooling efficiency is largely the result of where the car spent much of its life. Most deposit inside a cooling system come from thewater component of the coolant, prior to the era of Premix solutions, and cooling systems from New Mexico generally contain large rocks. Local water can kill a battery, and will generally diminish cooling system efficiency. Therefore, it's necessary to KNOW the Ph of the water you're using for cleaning as well as cooling. There is also the matter of both dissolved and suspended minerals and other solids in the water, which filtration might remove.

Moving forward from the position the water is good for use, My personal preference for the job is to first add some Polysorbate 20 to the coolant in situ, and put a few miles on the vehicle. Polysorbate is a wonderful product, you find it in everything from ice cream to Minoxodyl (read that label and save money) because it emulsifys better than anything else at the price. Ideally, with the thermostat removed, I will then reverse flush the system by introducing water to the lowest possible point on the block and blow the coolant and emulsified crap out the radiator neck with the engine running, beginning at a low rate of replacement. I also like to continue this flush until I have clear water showing at the neck. At that point with flushing shut off, I'll introduce Oxcalic acid to the circulating system, and possibly more Polysorbate. Oxcalic is essentially nonharmful to iron, copper and aluminum, and will dissolve rust on the block as well as act as a cleaner. The Polysorbate will emulsify the crud the acid removes, and keep it in solution. This will work best hot, but will also work cold when using an external pumping system such as a flushing machine.. After a few hours I'll again flush this solution out the neck of the radiator to the point of seeing clear water coming from the neck.
At this point, my preference is to shut the system down, close the supply port to the engine, and put the Stant Pressure tester on the system for a few hours to indicate if a leak is present. My experience is that leaks generally show up as the system gets back to ambient temperature rather than at operating temoeratures.

If there are no evident leaks, my next step is to check the Ph of the water in the system. If it's neutral, drain and fill the system with coolant solution. If it's acidic, add soda to the water in the system and circulate for an hour or so before flushing and dumping.
Final step is filling with the coolant f your choice, and pressure test over a few hours of time.

For your convenience I've attached the relevent sections of the Patent for an early coolant system flushing machine/syste,.

0033] An exemplary cleaning solution composition comprises water, 0.1 to 99 weight percent (wt%) of oxalic acid, 0.001 to 4 wt% of an azole compound, 0 to 10 volume percent of ethylene glycol, 0 to 20 wt% of maleic acid or maleic anhydride, 0 to 20 wt% of an organic phosphate ester, 0 to 20 wt% of an organic acid having a pKa less than 5.0 at 250C (other than the oxalic acid and maleic acid), and 0 to 5 wt% of an acrylic acid or maleic acid based polymer.

Walter Suiter
04-22-2017, 03:34 AM

[0034] The cleaning solution can have a pH less than or equal to 5.0, or more specifically less than or equal to 4.5, or, more specifically, less than or equal to 3.5, or, more specifically, less than or equal to 2.5, or, more specifically, less than or equal to 2.0, or, more specifically, less than or equal to 1.8, or, more specifically, less than or equal to 1.5. The pH of the cleaning solution is determined at room temperature
[0035] Typically any heat transfer fluid present in the heat transfer system is drained prior to cleaning. The heat transfer system can be flushed with water prior to adding the cleaning solution to the heat transfer system and drained. Some heat transfer systems are difficult to drain and retain a significant amount of the previously circulated fluid. The heat transfer system is filled with the cleaning solution. The engine is started and run for a period of time which can be for a few minutes to several hours. The cleaning solution can be recirculated. The cleaning solution can be recirculated by an internal pump (i.e., the water pump in a vehicle engine) and/or one or more external pumps in the cooling system to be cleaned. Alternatively, the cleaning solution can be gravity fed into the system. Additionally, a filter, such as a bag filter, can be used during the recirculation of the cleaning solution. The filter can be installed in a side stream of the recirculation loop or in a location of the system so that it can be removed or exchange easily during the cleaning process without interruption of the circulation of the cleaning solution in the main part of the system. The filter can have openings or pore size of 10 microns to 200 microns. After the cleaning is completed, the engine is shut off and the cleaning solution is drained from the system and the system is flushed with water.
Sec 36
An exemplary cleaning procedure utilizes an external pump and a fluid reservoir open to atmospheric pressure. The external pump and fluid reservoir are used to circulate fluid through an automotive cooling system. The heat transfer system is flushed of heat transfer fluid and filled with water. The thermostat is removed and a modified thermostat is installed to simulate an "open" thermostat condition. The procedure utilizes a reverse flow design through the heater core and ensures flow through the heater core. Gas generated in the system is purged through the system and discharged into the reservoir. The external pump draws cleaning solution from the reservoir, sends it into the heater core outlet, through the heater core, out of the heater core inlet hose, and into the heater outlet nipple on the engine. A discharge hose is connected from the heater inlet nipple on the engine back to the reservoir. An optional filter may be used on the discharge hose into the bucket to capture any cleaned debris. The vehicle engine is used to develop heat in the cleaning solution, but can only be run as long as the temperature of the cleaning solution remains below the boiling point. The system can be allowed to cool and the engine can optionally be restarted to reheat the solution but again the engine is only run as long as the temperature of the cleaning solution remains below the boiling point. The cleaning solution in the reservoir can be replaced between heating and cooling cycles. Additional cleaning solution can be added during a heating cycle to keep the temperature of the cleaning solution below the boiling point. The cooling step and reheating step can be repeated until the system is considered clean. The cleanliness of the system can be evaluated on the basis of the appearance of the cleaning solution. After circulating the cleaning solution the heat transfer system is flushed with water.

[0037] A conditioner can be used to passivate the heat transfer system after cleaning with the cleaning solution. The conditioner can comprise water, a water soluble pyrophosphate such as tetra-potassium pyrophosphate, in an amount of 0.5 to 80 weight percent, one or more azole compounds in an amount of 0.05 to 5 weight percent, alkaline metal phosphates, such as sodium phosphate or potassium phosphate, in an amount of 0 to 10 weight percent, alkaline metal polyphosphate, such as sodium tripolyphosphate, in an amount of 0 to 5 weight percent, and optional components, such as corrosion inhibitors, scale inhibitors, colorants, surfactants, antifoams, stop-leak agents (i.e., attaclay or soybean meals) etc. Amounts in this paragraph are based on the total weight of the conditioner.

[0038] The pH of the conditioning solution can be greater than or equal to 7.5 at room temperature (15 to 250C), or, more specifically, greater than or equal to 8.0, or, more specifically 8.5 to 11.

[0039] The conditioning solution is introduced to the heat transfer system in a method the same as or similar to that of the cleaning solution. Similar to the cleaning solution the conditioning solution should be circulated at a temperature less than the boiling temperature of the conditioning solution. The temperature of the conditioning solution can be between ambient and 800C.

[0040] After the optional conditioner is removed and flushed from the heat transfer system the heat transfer fluid is added. [0041] The heat transfer fluid can be a glycol based heat transfer fluid comprising an aliphatic carboxylic acid or salt thereof and/or an aromatic carboxylic acid. The heat transfer fluid can further comprise an azole, a phosphate, or a combination thereof. In addition, the heat transfer fluid also contain water, one or more glycol based freeze point depressants, and an optional pH adjusting agent to adjust the pH of the heat transfer fluid to between 7.5 to 9.0.

This thread on Steel Soldiers offers 3 additional "cleaners" 2 of them being dishwashing products primarily Sodium Silicate based.

John ED Renstrom
04-22-2017, 12:07 PM
or you can do like I do and when the green gooey stuff shows up under it see were it coming from if it's rubber replace it if its the radiator and it a GM cross flow decide if replacement is cheaper then repair. then go get the cheapest mix it your self antifreeze off the shelf cut it 50/50 with tap water. run the car around a bit, then park it. the neck morning is there is no green stuff under the car we make sure that fluid is at the proper level and go about our business.

with the understanding if it was not running hot before it most likely won't start after.

of course there is no substitute for proper maintenance to prolong the life of the car.

Kenny Dreher
04-22-2017, 12:30 PM
take vehicle and credit card to quickie lube. ask for flush and fill. drive home. repeat in a couple of years

Nicholas Studer
04-22-2017, 01:11 PM
Walter - thank you for taking the time as a new forum poster to write such a detailed review of your thoughts on this topic.

Please do join the PCS! :)

Walter Suiter
04-22-2017, 03:23 PM
or you can do like I do and when the green gooey stuff shows up under it see were it coming from if it's rubber replace it if its the radiator and it a GM cross flow decide if replacement is cheaper then repair. then go get the cheapest mix it your self antifreeze off the shelf cut it 50/50 with tap water. run the car around a bit, then park it. the neck morning is there is no green stuff under the car we make sure that fluid is at the proper level and go about our business.

with the understanding if it was not running hot before it most likely won't start after.

of course there is no substitute for proper maintenance to prolong the life of the car.

PLEASE, I beg you, do NOT use tap water. Distilled water is CHEAP.
More radiators and batteries get killed prematurely by tap water than any other cause.

Fill a clean glass jar with your tap water, put it o the shelf for a year, and examine what's on the bottom of the jar.
I made damn good side money from Dentists getting their tools back in working condition for years because they refused to believe tap water was loaded with contamination.

John ED Renstrom
04-22-2017, 11:00 PM
my tap water has a lot of minerals. you drink it with a spoon. been using it for the propose I described for about 58 years now. were I like Nick enjoyed your vary thorough explanation of what is best and why. I could see the chemistry and fallow it threw. there is no place to buy distilled water for 60 miles around. a battery in this country will go about 5 years. I can't tell you the last time I have added any water to one.

unlike the rust belt and east cost in general, in this desert climate rust it not a big problem. hail, now that is a problem but not rust. so as long as one changes the coolant every now and then to keep the acid build up at bay we don't have those problems. tell I got on this forum I have never heard of changing a steel brake line. it is just something we never need to do here. so for us it's a little dawn dish soap to clean the mud out and back flush with the garden hose. we have 100+ lb line presser in the main here so plenty to flow to do a good enough job for here. I marvel at the length people living elsewhere need to go to keep there cars. I have not gotten one from there that I did not have to replace the radiator and heater core. now I know why.

Walter Suiter
04-23-2017, 02:53 AM
John, have ypu ever seena printout of what the minerals in your water are?

Rochester gets water primarily from Lake Ontario, the world's largest sewer when you consider all the cities upstream flushing toilets into it, and we don't even want to talk about the Estrogen level. My bud has a beautiful well, with just a bit of lime. Well is fine for radiators and such, but not good for batteries.

In discussions such as cooling systems I try to keep at the front of my mind the differences in tap water around the country. Therefore I generally recommend distilled or even demineralized water.
A quick and dirty way of evaluating local water is either a steam iron (I hope somebody else remembers those) or a tea kettle. Look at the bottom of either after a few months and you have an idea what is happening in your cooling system.

Ph of the water is also quite important. Our rain water here is so acidic it needs to be buffered before you can use it for much chemistry as we've learned in rust removal tanks over the years. Ground water can go either way depending on well location, which is probably a result of this area being glacial deposit primarily.

Just back flushing with the thermostat removed isn't a bad way to go if you follow the path I outlined above. Vehicle water pumps are really circulaters, so there is plenty of space to blow crud back around the impeller.

If all else fails after you flished and you see squirting from the core or block, course ground black pepper and 3 or 4 eggs whipped up will get you home.

BTW, a lot of this game changes on vehicles made in the 50s. They were built for alcohol, not glycol.

Walter Suiter
11-08-2017, 09:56 PM
Update; Cummins is selling 2 varietys of cooling system cleaner, one alkaline and the other acidic.

The link offers good information.

My only hesitancy in using the PLUS variety on an old cooling system would be with regard to its property to remove deposited silicates, which may be plugging minor leaks that could become worse. I definitely wouldn't use it on a system where a StopLeak product has been employed.

Peter Grave
11-08-2017, 10:43 PM
When I had my 87 Buick Grand National Turbo the other Grand National owners began to have cooling problems. Solution was use strait Anti Freeze (not coolant) and distilled water no minerals NOT tap water problem solved. Remember coolant is just anti freeze with water added its not distilled water just coolant Companies tap water.

Paul Steinberg
11-08-2017, 10:55 PM
........ Remember coolant is just anti freeze with water added its not distilled water just coolant Companies tap water.

A while ago, probably 4 or 5 years ago, I contacted a couple of companies that offered premix antifreeze, and asked the question about the type of water that they used. They all said the same thing... "the water is PH balanced at neutral, and it is mineral free".

John ED Renstrom
11-08-2017, 11:31 PM
So if it is alkali that add acid and if it is acid they add baking soda to there tap water.

Peter Grave
11-08-2017, 11:41 PM
I would love to be a believer BUT!!! And remember over half the cars that go to AMCO don't need a new transmission BUT!!!! I will stick with strait anti freeze and the distilled water just don't trust em.