Negative Effects of Chlorine and Sulfur on Your Machines

Just say no to chlorine and sulfur.


If we suggested that pouring bleach in your engine would improve fuel mileage, would you do it? Of course you wouldn't. The risk verses reward is not worth it.
Below is what happens when you put a corrosive material in contact with metal.....

  • Because they are so corrosive, the oil industry stopped using chlorine compounds as engine-oil additives more than 40 years ago.
  • You, too, should reject any product that contains chlorinated hydrocarbons.
  • We personally sent samples of both [Dura-Lube and Prolong] products to a respected lab for analysis of chlorine content. Dura-Lube tested at 6.8 percent chlorine, while Prolong came in, incredibly, at just under 30 percent. For what it's worth Motor-Up was shown to contain 17.9 percent chlorine.

Only ASTM and SAE approved engine test protocol results are meaningful, and neither of these companies [meaning Dura-Lube nor Prolong] have proven its product performance under test conditions sanctioned by these industry-recognized organizations.

Chlorine (Cl) Overview: Chlorine is a chemical element in the halogen group, and is the second lightest halogen after fluorine. The element is a yellow-green gas under standard conditions, where it forms diatomic molecules. It has the highest electron affinity and the third highest electronegativity of all the elements; for this reason, chlorine is a strong oxidizing agent. Chlorine has many uses and serves in a variety of roles:

  • In the form of chloride ions, chlorine is necessary to all known species of life.
  • Other types of chlorine compounds are rare in living organisms, and artificially produced chlorinated organics range from inert to toxic.
  • In the upper atmosphere, chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion.
  • Small quantities of elemental chlorine are generated by oxidation of chloride to hypochlorite in neutrophils, as part of the immune response against bacteria.
  • Elemental chlorine at high concentrations is extremely dangerous and poisonous for all living organisms, and was historically used in World War I as the first gaseous chemical warfare agent.

Free chlorine is rare on Earth, and is usually a result of direct or indirect oxidation by oxygen. The high oxidizing potential of elemental chlorine led commercially to free chlorine's bleaching and disinfectant uses, as well as its many uses of an essential reagent in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride (PVC), as well as many intermediates for production of plastics and other end products which do not contain the element. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used more directly in swimming pools to keep them clean and sanitary.

So, what happens when chlorine containing technologies are added to the motor oil used in engines?

Chlorine Additives Cause Corrosion: Consumers frequently encounter “engine treatment” products containing chlorinated additives because chlorine reacts with the metal substrate to form a reactive species, or an oxide, which becomes a friction barrier … and produces dramatic demonstrations on ‘bench tests’. However, the by-product of oxidative chlorine causes problems in both engines and the environment. Chlorine is extremely reactive, making it corrosive to engine metals and interactive with many motor oil components. Further, chlorine’s long-term corrosive attack can outweigh any short-term benefits. Therefore, the addition of lube supplements containing chlorine, when added to motor oils, is akin to rolling the dice with the engines short and long term performance … it’s risky.

Where Chlorine Use in Lubes Makes Sense: Chlorinated additives react quickly with metal surfaces due to high electron negativity. Therefore, chlorinated additives are sometimes used in industrial cutting fluids designed to meet the extreme pressure requirement of metal machining. Metal machining involves a “one pass” metal shearing operation in an open system with constant flushing, conditions not conducive to corrosive attack (like it would be if used in motor oil that is constantly recirculating within your engine). Interestingly enough chlorine gas reacts with most organic compounds, and will even sluggishly support the combustion of hydrocarbons.

Hydrochloric Acid Corrosion – The Long-Term Impact: Internal combustion engines involve a closed loop system with conditions described by Mr. Maurice LePera, who served as Associate Director for Fuels and Lubricants at the U.S. Army’s Tank - Automotive Research Development and Engineering Center, in the August, 1998, Lubes-n-Greases article “Chlorine & Engine Oils: A Good Mix?”: “Chlorinated additives are not used in modern, fully formulated automotive engine oils. The environment within an internal combustion engine consists of high temperatures, combustion and blow-by gases, moisture, acid and oxidation precursors, wear debris, unburned fuel, etc. The combination of these ingredients when combined with the catalytic effects of metallic surfaces and trace soluble metals such as copper will cause the chlorine to hydrolyze, forming hydrochloric acid and other associated reaction products. Once generated, these acidic reaction products can cause serious internal engine corrosion problems, especially on ferrous and aluminum alloys.”

Considering the ferrous and aluminum nature of the most modern engines, one must seriously consider the use of chlorine-containing supplements if engine durability and longevity are important criteria.

Specifications – They Prohibit Chlorine: The reality of engine operation is that the corrosion inhibitors, which are added to motor oil formulations, are simply a short-term fix that leaves engines prone to corrosion after they do their job (are consumed) and lose their effectiveness. Certain chlorinated additive manufacturers claim that their products are non-corrosive. Unfortunately for consumers the corrosion process is not visible to the vehicle operator, and thus can continue unabated until the cumulative effects induce engine malfunctions and failures. Again, quoting Mr. LePera: “Corrosion within an engine can be a ‘silent killer.’” These concerns are supported by military lubricating oil specifications and commercial specifications prohibiting use of chlorinated additives.

Chlorine – An Engine Component Damage & Environmental Risk: Further, Mr. Cliff Gottlob of Gottlob Research and Engineering reports: “This [by-product of chlorine in engines] is a very corrosive product that is not only detrimental to such components as bearings, pistons and any metal parts, but also the environment. ... The devastating effect of chlorine on such items as rubber, neoprene, cork and compositions which are basic ingredients used in seals, gaskets, etc., is extremely bad.”

Lube Supplement Labels - Can Dodge The Real Issue: Unfortunately, many chlorine additive container labels do not state, “Contains chlorine.” Technically, chlorine in its pure form is a gas, so these products dodge the issue by using chlorinated; hydrocarbons, paraffin’s, solvents, etc. If the additive container label states, “Contains no PTFE, graphite, molybdenum disulfide or solids,” the product may likely contain chlorinated additives. And in some cases, the label may claim it contains moly or PTFE or whatever, but then they use chlorine to illustrate wear protection capabilities – especially during bearing wear demonstrations.

Trick Demonstrations: Due to chlorine’s quick reactivity, promotional demonstrations such as oil-less engine operation and friction bearing testers prove attractive to the unwary consumer. However, note comments from syndicated newspaper column Drive It Forever by leading automotive expert Mr. Bob Sikorsky, member of the SAE and STLE, nationally syndicated automotive columnist and author, and recognized consumer advocate:“Sadly, a number of these [chlorinated additive] infomercials use trickery and deception to convince the public to buy the product. ... The demonstrations shown in these infomercials are meaningless, and have nothing to do with what actually happens inside an engine during operation. ... The downside, which of course is never mentioned, is that it’s extremely corrosive." Further he states, “Choosing the right product could mean the difference between real 50,000-mile engine wear protection, and an engine hosting unproven possibly dangerous formulations.".

Only ASTM- and SAE-approved engine tests are meaningful, and neither of these companies [Dura-Lube and Prolong] has proven its product under these industry-recognized testing procedures.”

Longevity – Chlorine’s Impact: An October, 1998, Consumer Report article, “Prolong additive: Don’t try this at home,” addressed the infomercial demonstration issue: “The bond is supposed to last even when the oil is drained. In the [Prolong] infomercial, Unser and others drive along a racetrack in the Mojave Desert without oil or oil drain plugs. The same ad, broadcast nationally, pictures a woman who, thanks to Prolong, supposedly drove from Santa Barbara to Los Angeles without oil. (The reason she stopped after 4 hours, 40 minutes, and 7 seconds? She was hungry.)" We didn't test the other claims, but we did see whether Prolong would protect an engine after the oil was drained. “We installed a factory-rebuilt GM 4.3-liter V6 engine into each of two Chevrolet Caprices. We broke them in with Pennzoil motor oil, and added Prolong to one of them. Prolong claims to work immediately. We drove more than 100 miles, then drained the oil and started driving again. After only 13 minutes and five miles, both engines failed simultaneously.”

Lab Analysis Comments: Lab results indicate the product provided for analysis contains:

839 ppm Cl (chlorine)

57,300 ppm S (sulfur)

Chlorine: The provided product contains chlorine and with that, the associated risks as commented on above. Since we have already addressed the chlorine impact ... let’s look at sulfur.

Sulfur: For many years the use of sulfur-phosphorus (S-P) additive chemistry has been a mainstay of EP (extreme-pressure) lubrication. It works, but does have temperature sensitivities. Most gearboxes are designed to run at 140°F or less. The reason for this is the S-P EP additive package. What happens at a microscopic level is the S-P package is thermally activated creating a chemical reaction that is so violent that the turbulence separates opposing metal surfaces from coming into contact with one another. Therefore what one should really ask is; “What is the difference between total sulfur and active sulfur contents in extreme pressure additives? How does sulfur (both forms) increase extreme pressure (EP) characteristics?”

Sulfur is used in many EP oils and metal-working fluids as an EP additive. The basic way this works is for the sulfur to react at elevated temperatures, such as those experienced by meshing gears to form a sulfide layer. For example, for steel gears, an iron sulfide layer forms on the gear tooth surface. This ductile layer improves sliding contact, preventing scuffing or galling. There are two types of sulfur compounds used — active and inactive sulfur. The main difference is that for active additives, the sulfur-containing additive reacts with the surface at much lower temperatures, whereas inactive compounds react only at much higher temperatures. While active additives have advantages of greater reactivity and hence may offer better anti-scuff protection, especially at lower temperatures, they are also mildly corrosive, particularly to yellow metals (brass, bronze, etc.), and should be avoided where these alloys are present. The amount of active sulfur additive can be measured by first determining the total sulfur content using an appropriate ASTM test method, then reacting the active sulfur with copper powder and removing the copper sulfate by filtration, and again measuring the remaining total sulfur.

Extreme Pressure (EP) Additives: EP additives for lubricants serve a role to decrease wear of the parts of the gears exposed to very high pressures. Again, one of the most common is sulfur-phosphorous EP additives. They are also added to cutting fluids for machining of metals. EP additives are usually used in applications such as gearboxes, while AW (anti-wear) additives are used with lighter load applications – such as that require hydraulic fluids and automotive engine oils. The reason for this is again tied to temperature sensitivity, meaning that the AW additives can operate in an environment where higher operating temperatures are the norm (i.e. hydraulic systems and engines).

EP additives typically contain organic sulfur, phosphorus or chlorine compounds, including sulfur-phosphorus and sulfur-phosphorus-boron compounds, which chemically react with the metal surface under high pressure conditions. Under such conditions, small irregularities on the sliding surfaces cause localized flashes of high temperature (300-1000 °C), without significant increase of the average surface temperature. The chemical reaction between the additives and the surface is confined to this area.

Sulfur in Motor Oils: EP gear oils perform well over a range of temperatures, speeds and gear sizes to help prevent damage to the gears during starting and stopping of the engine. Unlike AW additives, EP additives are rarely used in motor oils. The sulfur or chlorine compounds contained in them can react with water and combustion byproducts, forming acids that facilitate corrosion of the engine parts and bearings.

What All This Means: Without knowing more about the specific chemical links carrying the sulfur in the submitted lube supplement additive, it is impossible to comment on specific properties and outcomes. That said, one must recognize that with engines running at a controlled operating temperature of 210-220°F (to cook of water) that one must concern themselves about the long-range impact the addition of sulfur to motor oil will have on associated acid generation and corrosive wear.

Hopefully this provides you with the insights you were looking for to compare the lube supplements offered by Petron Plus, to the lube supplement you using (and others like it). The technology we present is 100% biodegradable, and contains no chlorine. It works and is supported by a 35+ year track-record of success in applications ranging from normal to severe. Please do not hesitate to let me know if you have any additional questions

Below is an example of a company that claims to not have Chlorinated solvents in their product. Yes that is true, it does not contain Chlorinated solvents, but it contains Hydrogen Chloride gas. Still Chlorine...It's very Misleading...

mt-10 metal treatment

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