Cooling System Treatise for the Heavy Duty Diesel Engine

George R. Sturmon, P.E.

Executive Summary

This paper is based on the fact that any meaningful dialogues on present and/or future emission regulations must consider clean cooling system operation and maintenance.

It covers a long and exhaustive study in the tested and proven benefits of a clean cooling system in the heavy duty diesel. Because cleaning a cooling system with stan dard methods is difficult, time- consuming, and messy a new and unique cleaning method was used; the Enviro-Cool^TM Cleaner/Filter . The test results reported in this paper are dramatic.

Included is a discussion on the history of cooling system problems recognized 30 years ago to present day concerns of EPA regulations as they will affect diesel engine cooling systems past, present and future.

The test data study covers seven years of operation on a 650 diesel fleet running 25 million miles each year. To be totally objective the fleet was broken in two groups; older, high mileage vehicles and new, low mileage vehicles. Data from both test groups is absolutely unambiguous as to the value of a clean cooling system in terms of effective cooling, money savings and fleet productivity.

Introduction

For 30 years diesel engine users have been told that cooling system problems caused at least 50% of all premature engine failures. Now, suppliers and users alike are concerned and generally in the dark on the exact changes in methods necessary for engines and cooling systems to meet 2002 and beyond emissions regulations as well as retrofit requirements possibly back to 1986 models.

Most major engine manufacturers are expected to use Exhaust Gas Recirculation (EGR) systems on diesel engines to help them meet stricter EPA emissions effective in 2002. EGR will affect oil, oil drain intervals, filtration, etc. because of additional heat loads.

This additional heat load must be controlled by coolants and the cooling system. If not, the percent of premature engine failure due to cooling system problems will increase dramatically above the old 50% number.

No matter what new products or methods are used, there is one irrefutable fact that stands out: cooling systems must be clean and kept clean to do their job effectively. The old adage is still correct - Good Cleaning means Effective Cooling. Without effective cooling, no engine will stand up under the new EPA regulations.

History

In the mid 1980's, there was much talk about long life inhibitor filters - those that would last up to a year instead of monthly replacements to maintain inhibitor levels. But, inhibitor filters require a clean cooling system at the time of installation. At that time, the only available method of cleaning and protecting the diesel cooling system was to drain, flush, dilute the cleaning chemicals and then refill the engine - a process that produced inconvenient and costly downtimes. What was needed was a cleaner that would conform to the typical method of truck maintenance - a spin-on filter. One must understand the importance of starting with a clean cooling system to increase vehicle productivity by allowing regular and necessary maintenance to be as easy as installing a spin-on filter.

The search was on to find the same chemical technology in a dry or pelletized form to be used in a spin-on filter to replace the diluted liquid cleaning methods. After a few years, the proper combination of concentrated dry chemicals was found that exceeded the performance of liquid cleaners.

The Enviro-Cool^TM Cleaner/Filter is installed once a year and cleans the diesel engine coolant by sending out chelating agents to combine and remove system contaminants that form as a result of coolants reacting with water impurities and natural corrosion of system walls. After 30 days , the cleaner is removed and a standard inhibitor/filter is installed in its place.

Because it is a spin-on filter, the Enviro-Cool^TM Cleaner/Filter conforms to the typical method of vehicle maintenance. There is no costly downtime or expensive maintenance charges. Enviro-Cool^TM provides a way to keep diesel engines cooling system clean and cooling effectively without the inconvenience of disposing of toxic wastes created by draining, flushing, and mixing chemicals.

Technical Information That Led to the Development of the Enviro-Cool^TM Cleaner/Filter

Diesel engines for both on and off-road vehicles usually operate at high temperatures. At these elevated temperatures, supplemental chemical additives (SCA) in the coolant combine with the hard water, solder acids and corrosion products in the cooling system to form a gel, solder bloom and/or contaminants. These may consist of calcium silicates, calcium phosphates and magnesium silicate. The gel and solder bloom will eventually restrict the flow of the coolant through the cooling system and result in an inability to properly cool the engine or heat the cab of the vehicle. The engine block and liners are also subject to build-up of scale, rust and corrosion products, which cause hot spots, sticking thermostats, and failed water pump seals. Both the overall overheating and the localized heating lead to such problems as increased oil temperatures, premature water pump failure, scuffed cylinder liners, erosion, and cracked or warped heads.

To effectively clean a diesel cooling system with standard cleaners, the system must be treated by draining and flushing the engine, then mixing and adding a liquid cleaning agent, running it through the engine for three to four weeks, then again draining and flushing the cooling system to remove the loosed particles and then filling it again with coolant. These cleaning liquids that are currently on the market must be diluted before they are added to the system to prevent localized damage to the system. This method of cleaning is both complicated and expensive in that it requires considerable labor and substantial vehicle downtime. Therefore, it is not uncommon for diesel engine cooling systems to go for long periods of time without cleaning, or possibly never be cleaned at all.

The cooling system of a heavy duty diesel engine differs from that of other internal combustion engines in that it includes a filter for removing loose debris from the circulating coolant. The coolant filter is a by-pass filter, which typically sees all of the coolant in the system over a period of about sixteen to twenty cycles of the water through the system. Currently, rather than add inhibitor mixtures to the cooling system directly as concentrated solutions, they are frequently added to the system in a dry pellet or pellets in the coolant filter. So herein lies the problem that led to the development of the Enviro-Cool^TM Cleaner/Filter : adding the inhibitor mixtures to a dirty or corroded cooling system may be worse than adding no inhibitors at all. Inhibitors do not dissolve corrosion products or gel which have already formed. Thus, adding such chemical inhibitors to a dirty or corroded cooling system may cause scale or corrosion to break off in chunks, damaging surfaces it comes into contact with.

The foundation of the Enviro-Cool^TM Cleaner/Filter is based on the premise that it all has to start with a clean cooling system. Once a system has been cleaned, the introduction of inhibitor mixtures to protect against further corrosion and contamination is recommended and more effective. Some of the common sources of this contamination are:

• Water used in the 50/50 blend with antifreeze
• Mineral content in water has long been known to cause cooling system contamination by producing various types of scaling and salts as well as adverse chemical reaction with the antifreeze.
• Overtreating or undertreating with inhibitors
• The manufacturers of SCA's and antifreezes warn about undertreating and overtreating. Undertreating allows rust and increased scale formation as well as liner pitting. Overtreating can cause "green goo", chemical drop out and water pump seal failure.
• Air being introduced into the cooling system by a leaky radiator cap or simply removing the cap for a make-up or refill
• Air is an oxidizer that chemically reacts with various minerals and metal to get iron oxide and support salt formation.
• Replacing worn or failed cooling system parts with new but contaminated parts
• Keeping cooling system parts sealed while stored on the shelf is not an easy task.
• Solder bloom caused by the chemical reaction between the acid in the solder and coolant chemicals/antifreeze.

While this list is not complete it is obvious that contamination is a condition that diesel engine users must contend with no matter the coolant additives, antifreeze, or cooling system maintenance program used.

How the Enviro-Cool^TM Cleaner/Filter Works

The goal was to provide a simple, inexpensive, and effective method for cleaning the cooling system of an internal combustion engine, particularly a diesel and to provide such a method that would not require downtime of the vehicle by eliminating the need to mix chemicals, drain, and flush the cooling system.

The patented closed system cleaner formula is converted from a powder to a pellet form and enclosed in the cooling system filter cartridge by the Enviro-Cool^TM manufacturing process. The Enviro-Cool^TM Cleaner/Filter is in a spin-on filter that allows the pellet to dissolve and enter the coolant slowly enough as to form a generally homogenous mixture of cleaning agent throughout the entire volume of coolant in the system. Therefore, localized damage to the system is prevented, while permitting sufficient cleaning agent to be added to provide effective cleaning. The Enviro-Cool^TM Cleaner/Filter is removed after a period of approximately one month and replaced with a standard inhibitor filter.

The Test Results

Statistical data and field tests have supported the claim that PREVENTIVE annual cooling system cleaning with the patented Enviro-Cool^TM Cleaner/Filter saves time and money in the following typical ways:

• 100% reduction in clogged radiator and clog related overheats
• 50% reduction in heat-related engine failures with no failures due to internal cooling system problems
• 50% reduction in radiator and oil cooler replacements
• 80% reduction in defroster core replacements
• Water pump failures reduced by 80%
• Reduced anti-freeze usage by 35%
• Overall cooling system efficiency increased by 30%
• Locking-up thermostatic fan controls is no longer necessary in hot weather
• Elimination of man-hours spent cleaning cooling systems
• Elimination of harmful internal deposits in cooling systems

Fleet Condition Prior to Test - Problems Prompting Field Test

The tests were conducted in a fleet that operated 650 diesel-powered vehicles in daily revenue service, running in excess of 25 million miles per year. For definitive test purposes, the fleet was split into older, high mileage vehicles and newer, low mileage vehicles. Cooling system problems prior to the test included:

• Solder bloom and silica gel drop out problems
• Downtime and progressive damage from various cooling system failures.
• Labor intensive cooling system cleaning procedures
• Excessive anti-freeze usage
• In hot weather the engine fan thermostatic controls were bypassed so fans would run at 100% engine speed

Pretest Cooling System Condition

Prior to the test, data was collected and reviewed on the units selected for the test to ensure a more accurate analysis of condition before and after the introduction of the Enviro-Cool^TM Cleaner/Filter .

At that time, the cooling system maintenance and cleaning consisted of maintaining the supplemental coolant additives (SCAs) through the use of inhibitor filters, pre-charging the SCAs in liquid form, and monitoring the total dissolved solids (TDS) every 12,000 miles. When the TDS reached 2000 the system was drained, refilled with water and a cleaning product, run in the shop to circulate the cleaning products, then drained again, flushed and refilled with new anti-freeze. The SCA were pre-charged in liquid form, and a new inhibitor filter was installed.

Since this process was labor int ensive and relied heavily on accurate and consistent test procedures, it was not always successful. For example, an audit of SCAs and TDS performed, showed that only 40% of the vehicles tested were within acceptable limits, and most of the others tested were too high in TDS. This indicated the systems were not being cleaned as required, presumably because cleaning was labor intensive, expensive and messy.   The location that had the best results were cleaning the cooling systems and changing the anti-freeze on an annual basis.

Fleet "A" Test - On Older, High Mileage Vehicles: Procedures and Conditions

It was decided that the test would be on some units which had been in service nine years before testing began and had accumulated mileage of approximately 350,000 miles each.

To test the effectiveness of the cleaning performed by Enviro-Cool^TM Cleaner/Filter , the following procedure was instituted: run the vehicle on the chassis dynomometer to operating temperature; check and record the temperature drop across the radiator and record it; check and record the fan speed; check coolant and record the freeze point, total dissolved solids and nitrate level; and remove the inhibitor filter and install the Enviro-Cool^TM Cleaner/Filter and record the date and miles.

Conditions prior to the test included:

• At engine overhaul, all radiators over 6-months old were flow tested to determine if they were reusable; 95% of the radiators would not pass a flow test due to internal restriction from deposits.
• Radiators were being replaced at a rate of 18-20% of the fleet each year.
• Defroster cores were also being replaced at a rate of 17% per year.
• In hot weather, the engine fan thermostatic controls were bypassed so that the fans would run at 100% of engine speed at all times to compensate for poor flow through the radiator.

After installing the Enviro-Cool^TM Cleaner/Filter and running in daily service for 12,000 miles the vehicles were brought in for inspection. Significant results were found:

• Temperature drop across the radiators was reduced an average of three degrees
• In most cases total dissolved solids were not impacted to the point that a coolant replacement was required.
• There was no significant impact on nitrate levels

On one unit, a radiator that would not pass a flow test was installed along with an Enviro-Cool^TM Cleaner/Filter and run for 6,000 miles. The radiator was then removed and retested, with no special procedure or rodding of radiator tubes. This previously clogged radiator now passed the test. The total dissolved solids in the anti-freeze did not increase appreciably, so the anti-freeze was reused. In addition, several radiators were removed, disassembled and inspected. They were free of scale, corrosion and silicate deposits.

On the remaining test units, vacuum reading were taken on the suction side of the radiators before application of the Enviro-Cool^TM Cleaner/Filters , and again after 6,000 miles of operation with the Enviro-Cool^TM Cleaner/Filters . The vacuum reading taken after the test showed an average 40-50% decrease in vacuum.

SCA are still maintained through the use of inhibitor filters, but in 1995 the Agency began using precharged anti-freeze to eliminate the use of liquid SCAs. SCAs are now tested with Detroit Diesel's power track test strips rather than by chemical titration. TDS are still monitored at 12,000 mile intervals, but now when the reading reaches 2,000 the system is simply drained and refilled.

Cooling System Performance

The following improvements were achieved in the tests with the use of the Enviro-Cool^TM Cleaner/Filter :

• Radiators are still being flow tested at engine overhauls. The fleet has not encountered a clogged radiator in approximately four years, compared to the 95% clogging in the pre-test period.
• Radiators for the test fleet are now replaced at a rate of 8-10% per year; the previous rate was 18-20%. The replacements are due to external or mechanical problems.
• Defroster cores are replaced at a rate of 3-4% per year; the previous rate was 15-18%.

It is no longer necessary to bypass the thermostatic fan controls in hot weather; since the use of the filter, we have n ot had a clog-related overheat.   Engine failures due to prolonged overheating have been reduced by a minimum of 50%.

Fleet "B" Test - On Newer, Low Mileage Vehicles: Procedures and Conditions

This fleet group was also monitored throughout the test period and was new to less than two-years old. At the beginning of the test, this fleet had accumulated very few miles, and had established no record of cooling system failure. These units have now been in service for nine years and have accumulated over 400,000 miles.

This test was started by simply applying the coolant cleaner filter on an annual basis. The maintenance of the SCAs and TDS was performed exactly the same as on the main test fleet. The cooling system performance on the second test group was:

• Radiator replacements have never exceeded 12% per year, even though these radiators are prone to clogging of the external fins.
• Defroster core replacements have never exceeded 3% per year.

It is apparent that the implementation of regular cooling system cleaning has kept the failures at a much lower rate than we experienced on buses that had been in service nine years with sporadic cleaning.

Conclusions

The manager of the fleet conducting these tests determined that cleaning with the Enviro-Cool^TM Cleaner/Filter is only necessary on an annual basis to maintain a deposit-free cooling system. No man hours are expended on cooling system cleaning, as this is accomplished by replacing the inhibitor filter with the Enviro-Cool^TM Cleaner/Filter on a regular preventive maintenance inspection.

Based on these results, the use of the Enviro-Cool^TM Cleaner/Filter was instituted as a fleetwide policy for annual cooling system cleaning.

For a copy of the SAE Technical Paper 1999-01-3720 on this test, ASTM tests, or for furthe r information, call Enviro-Cool, Inc., Sullivan, MO toll free at (877)741-2111.

How to Use the Enviro-Cool^TM Cleaner/Filter

The use of the Enviro-Cool^TM Cleaner/Filter is clean and simple.

First use test strips to determine if the inhibitor and coolant level is correct. Then spin-on the Enviro-Cool^TM Cleaner/Filter ; it cleans while the vehicle is in service. In 30 days remove it. Check the cooling system to make sure dissolved solids are within recommended levels and spin on your conventional inhibitor filter.

By using the Enviro-Cool^TM Cleaner/Filter once a year you should be able to go for five years without draining the cooling system.

The Enviro-Cool^TM Cleaner/Filter is compatible with current inhibitor and coolant packages and compliments the use of a recycler.

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Cooling System Cleaning Through the Use of a Chelating Cleaner Filter

Lyle Howard
Bi-State Development Agency

Abstract

A new method of cleaning cooling systems has been developed that uses a filter with a chelating alkaline cleaner that is released into the cooling system. The cleaner filter is installed in place of the inhibitor filter on heavy-duty engines and left in place for one service cycle. After the service cycle, the cleaner filter is reinstalled. This represents a major change in the method traditionally used for cooling system cleaning.

Introduction

A large Midwestern transit authority tested the cleaner filters and documented the results on two of its sub-fleets over a seven-year period. Data was collected and analyzed from a computerized maintenance management system, and all cooling system related entries were analyzed and separated into categories. The test was undertaken to address several costly cooling system maintenance issues:

• Solder bloom and silica gel dropout problems
• Labor intensive cooling system cleaning procedures
• Excessive antifreeze usage
• Downtime and progressive damage from various cooling system failures.
• The goal of the testing was to determine if the cleaner filter cleaner the cooling systems adequately, if it performed the cleaning task using fewer man-hours of labor, and if there were operational improvements to the equipment attributable to regular cooling system cleaning.

Testing and Analysis

Fleet Analysis, Prior to coolant Cleaner Filter Introduction

In the late 1980's and early 1990's cooling system maintenance consisted of maintaining the supplemental coolant additives (SCA's) through the use of inhibitor filters, precharging the SCA's in liquid form, and monitoring the total dissolved solids (TDS) every 12,000 miles. When the TDS reached 2000, the system was drained, refilled with water and a cleaning product, run in the shop to circulate the cleaning product, then drained again and refilled with new anti-freeze. The SCA's were precharged in liquid form, and a new inhibitor filter was installed.

Since this process was labor intensive and relied heavily on accurate and consistent test procedures, (nitrates were tested by chemical titration) it was not successful. An audit of SCA's and TDS performed in 1990 showed that only 40% of buses tested were within acceptable limits for nitrites and most of that 40% were too high in TDS. This indicated that the systems were not being cleaned as required, presumably because cleaning was labor intensive, expensive, and messy. The locations that had the best results were cleaning the cooling systems and changing the anti-freeze on an annual basis.

The effectiveness of the cleaner filter was most pronounced on a fleet of 1981 GMC buses with 8V71 Detroit Diesel engines. These buses had been in service for nine years and had accumulated average mileages of approximately 350,000 miles each. The following condition existed prior to the introduction of the cleaner filter.

• At engine overhaul, all radiators over six months old were flow tested to determine if they were reusable. 95% of the radiators tested would not pass a flow test due to internal restriction from deposits. Per Detroit Diesel, the radiator should be capable of a flow of 100 GPM at 2100 R.P.M. The tester was used independently of the engine to measure total flow capacity, which on a new radiator was 110 G.P.M. range
• Radiators in the subfleet were being replaced at a rate of 17% to 20% each year.
• Of the radiators replaced, 95% were internally clogged and would not pass a flow test.
• Defroster cores were being replaced at a rate of 17% per year. These also were clogging due to being in a low flow area of the cooling system.
• In hot weather, the engine fan thermostatic controls were bypassed so that the fans would run at 100% of engine speed at all times to compensate for poor flow through the radiator.

Cooling System Maintenance and Cleaning

In 1992, the Agency tested cleaner filters on a group of 1981 GMC buses. On one bus, a radiator that would not pass a flow test was installed along with a cleaner filter and run for 6000 miles. The radiator was then removed and retested, with no special procedure or rodding of radiator tubes. This previously clogged radiator now passed the test. Total dissolved solids in the anti-freeze did not increase appreciably, so the anti-freeze was reused. On the remaining test buses, vacuum readings were taken on the suction side of the radiators before application of the cleaner filters, and again after 6000 miles of operation with the filters. Vacuum readings should be close to a steady 1.5 in. Hg across the entire operating range in a clean, properly sized cooling system with a Detroit Diesel 8V71 engine. Vacuum readings taken before application of the cleaner filter were in the 2.0 to 2.1 in. Hg range. The vacuum readings taken after the test showed an average 40% decrease in vacuum.

Supplemental coolant additives (SCA's) are still maintained through the use of inhibitor filters, but in 1995 the Transit Authority began using precharged anti-freeze to eliminate the use of liquid SCA's. Data was analyzed on radiator replacement in the GMC subfleet from 1990 forward to determine if the reduction in replacements was attributable solely to application of the cleaner filter, or if the use of precharged antifreeze also had an effect. (fig. 1) The greatest reduction in radiator replacements occurred in 1992 when the cleaner filters were first applied. The introduction of precharged antifreeze in 1995 had no notable effect on radiator replacement rates. SCA's are now tested with test strips rather than by chemical titration. Total dissolved solids (TDS) are still monitored at 12,000-mile intervals, but now when the reading reaches 2000, the system is simply drained and refilled. It has been determined that cleaning with the cleaner filters is necessary on an annual basis to maintain a deposit free cooling system. No man-hours are expended on cooling system cleaning, as this is accomplished by replacing the inhibitor filter with a cleaner filter on a regular preventive maintenance inspection.

The following improvements were achieved with the use of the cleaner filter:

• Radiators are still being flow tested at engine overhauls. This Transit Authority has not encountered a clogged radiator in approximately four years. (vs. 95% clogging)
• Radiators for the GMC subfleet are replaced at a rate of 8-10% per year. (1/2 the previous rate)
• Defroster cores are replaced at a rate of 3-4% per year. (1/5 the previous rate)
• It is no longer necessary to bypass the thermostatic fan controls on the GMC's in hot weather. (Since the use of the filter, there has not been a clog related overheat)
• Anti-Freeze consumption fleet wide has been reduced 35%.
• Engine failures due to prolonged overheating have been reduced by a minimum of 50%

Another sub-fleet that was monitored throughout the test period was a fleet of 1988 Flxible buses. These buses have now been in service for eleven years and have accumulated over 400,000 miles per bus. At the beginning of this test, this fleet had accumulated very few miles, and had established no record of cooling system failure.

This test was started by simply applying the coolant cleaner filter on an annual basis. Maintenance of SCA's and TDS was performed exactly the same as on the 1981 GMC subfleet.

Cooling system performance:

• Radiator replacements have never exceeded 12% per year, even though these radiators are prone to clogging of the external fins.
• Defroster core replacements have never exceeded 3% per year.
• It is apparent that the implementation of regular cooling system cleaning has kept the failures at a much lower rate than was experienced on buses that had been in service nine years with sporadic cleaning.

Conclusion

The preventive cleaning of cooling systems with the cleaner filter has benefited the transit fleet in several ways:

• Reduced anti-freeze usage
• Elimination of internal deposits in cooling systems
• Elimination of man-hours spent cleaning cooling systems
• Reduced heat-related engine failures
• Recent fleet audits show that over 85% of the fleet is within specifications for TDS in the cooling system.
• Over the term of the test period, soft metal and elastomer components exposed to the coolant were inspected for any signs of degradation attributable to annual cleaning with an alkaline product. Particular attention was paid to injector tubes and 'o' rings, and tube to header soldered joints in radiator, heater, and defroster cores. The usage of these items over the test period remained almost constant, with radiator cores and injector tubes being replaced as required at the time of engine overhaul.
• Since coolant service life was being extended beyond the yearly replacement, samples were analyzed for by products of ethylene glycol degradation, as the coolant would exceed the TDS limit and be changed out prior to degradation of the ethylene glycol. Coolant changes after the introduction of the cleaner filter in 1992 were extended by as little as 60 days and as much as one year.

Based on these results, the use of the cleaner filter was instituted as a standard policy for annual cooling system cleaning.

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Test Results

Independent test results indicate that the Enviro-Cool^TM Cleaner/Filter will not harm or attack any engine cooling system components when used according to manufacturers prescribed cooling system maintenance procedures. Therefore, it is safe to use and no worry of potential damage to an engine.   Testing was performed by Amalgatech of Phoenix, AZ.

The Results:

Physical & Chemical Tests
The alkalinity (pH level) of the Enviro-Cool^TM Cleaner/Filter is up to the necessary level (11.0) for proper coolant inhibiting. The alkalinity level test results of the Enviro-Cool^TM Cleaner/Filter means the chemical in the cleaner will not attack non-ferrous metals.

Foaming Tendency
In the area of foaming tendency, we are concerned with size of bubbles and the length of time it takes for the bubbles to burst. The Enviro-Cool^TM Cleaner/Filter test results indicate that the bubbles created by the cleaner are very small and dissipate rapidly. The bubbles are only 1/10th the size of acceptable bubbles (acceptable is 150ml, Enviro-Cool^TM is 15ml). The acceptable bubble breakage is 5.0 seconds.   The Enviro-Cool^TM Cleaner/Filter created bubbles that dissipated in 1.5 seconds. Therefore, the Enviro-Cool^TM cleaner resists any potential engine cavitation problems.

Corrosion of Cast Aluminum at heat surface
The acceptable average weight loss is 1mg/sq.cm/week. The results indicated that the Enviro-Cool^TM sample test average weight loss is only .2mg/sq.cm/week. Therefore, there is a factor of a 5 to 1 margin. The pH after the test indicated that the Enviro-Cool^TM Cleaner/Filter maintains an acceptable alkalinity of 10.2 (acceptable range is 7.5 to 11.0). This is especially important with the Caterpillar engines with aluminum head. The chemical used in the Enviro-Cool^TM Cleaner/Filter forms a film on the engine cooling system components which resist corrosion.

Corrosion in glassware
Under the column "Max", the ASTM D 1384 standards are identified for copper, 30a solder, steel, cast iron, and cast aluminum. The Enviro-Cool^TM cleaning chemical beats all the standards by factors of 1/2 to 1/10 to no effect. All this means is the Enviro-Cool^TM Cleaner/Filter will not damage engine cooling system components.

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