Why Too Much Coolant Corrosion Inhibitor Can Be Harmful

What are coolant corrosion inhibitors?

Coolant corrosion inhibitors help decrease the corrosion rate of metals within your equipment and help maintain other coolant properties. The coolant manufacturers will determine the type of coolant corrosion inhibitors utilized in their product. The main types of inhibitors are:

  • Inorganic based (IAT)
  • Organic based (OAT)
  • Azoles

What coolant should I use?

The coolant you use while maintaining your equipment should utilize the same type of inhibitors as the coolant formulation that’s already in your system.

Here are some ways to make sure your fluid is able to properly protect your equipment:

  • Testing with test strips (see technical bulletin below)
  • Using fluid analysis laboratories
  • Following recommendations on how to maintain inhibitor for the specified fluid type

We know low corrosion inhibitors for heavy duty applications leave our equipment vulnerable to corrosion but, why is too much a problem?

Even though heavy duty equipment will require a higher level of inhibitors compared to light duty equipment, a specific range must be maintained for proper protection. Adding too much coolant corrosion inhibitor to the cooling system, no matter what type of inhibitors are utilized in the fluid, will impact other coolant properties. The pH and specific conductance will increase which will lead to corrosion concerns.

Another concern is the coolant’s saturation point. When the saturation point (where no more inhibitor can be absorbed in the coolant) is reached, the inhibitors will drop out and a precipitate will form. The precipitation will cause plugging of the coolant passage ways.

When this occurs the coolant will no longer be able to prevent corrosion of the metals that come in contact with the coolant.

What a coolant corrosion inhibitor drop out means

A major function of the cooling system will be impacted due to the drop out of coolant corrosion inhibitors. This important function is coolant flow. When the coolant cannot effectively circulate through the engine due to precipitation restricting coolant flow we lose our capability for heat transfer. Without proper heat transfer we will experience engine overheating and may cause further engine damage. Both scenarios of too little or too much coolant corrosion inhibitor will negatively impact your equipment and overall decrease your equipment’s reliability. Maintaining the correct coolant corrosion inhibitors in the recommended ranges per coolant manufacturer recommendations will provide the best protection for your equipment.

Below are some technical bulletins with additional information on coolants, coolant test strips and high performance liquid chromatography (HPLC).

Coolant and Cooling System Maintenance

Coolant Test Strips

Benefits from High Performance Liquid Chromatography (HPLC)

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Published October 8, 2019

Tips for Pulling a Fluid Sample for Analysis

From oils to coolants, from coolants to grease – we all have our own methods for pulling a sample. But are you truly getting the best representative sample to send for testing? An accurate, representative sample will get you the most reliable sample results, so you can take the correct maintenance action. Want to learn more about best practices for pulling a sample?  See below for some tips:

Oil and Coolant Samples

There are several methods for pulling oil and coolant samples including a vacuum pump, probing valve and a pushbutton method.

  • Tips for using a Vacuum Pump Method
    • Use to pull samples from a dipstick or non-pressurized system
    • Pull a sample when equipment is at or close to normal operating temperature
    • Make sure the tubing is long enough to reach the middle of the reservoir tank
  • Tips for using a KST Series Probing Valve Method
    • Use with valves installed on a pressurized system with a minimum of 4 psi to a maximum of 1000 psi
    • Pull sample when equipment is at or near normal operating temperature
    • Wipe the valve clean with a dry and lint-free cloth
    • Flush at least 3 times into a “waste container” under the valve to purge stagnant oil and debris.
    • Fill the sample bottle bottle approximately 3/4 full
  • Tips for using a KP Pushbutton Sampling Valve Method
    • Use with valves installed on a pressurized line with a minimum of 4 psi to a maximum of 100 psi
    • Pull sample when equipment is at or near normal operating temperature
    • Remove protective valve cap and wipe opening with a dry and lint-free clean cloth
    • Flush at least 3 times into a separate container and then dispose of the waste oil
    • Fill the sample bottle bottle approximately 3/4 full

For full, step-by-step instructions for taking an oil sample or a coolant sample with these methods, view our technical bulletins or view our Fluid Analysis Sampling and Submission video.

Fluid Analysis Sampling and Submission

Grease Samples

There are two methods for collecting grease samples including a standard grease sampler device or a T-Handle.

  • Grease Sampler Method
    • Each kit comes with a plunger, syringe, spatula and grease sampler used collect your sample
    • Collect grease from the component and fill syringe
    • Use the syringe to fill the grease sampler
  • T-Handle Method
    • Use this method to collect a representative sample when a spatula can’t reach the active zone
    • Attach the grease sampler to the T-Handle tool
    • Measure the appropriate depth of the sample by inserting the locking knob into the proper hole
    • Fully insert the grease sampler and T-handle into the component until the tee contacts the housing face

For full, step-by-step instructions for taking a grease sample with a grease sampler or using the T-Handle tool, view our technical bulletins or view our demonstration videos below.

How to Take a Grease Sample with a Grease Sampler

How to Take a Grease Sample with a T-Handle

After collecting your sample, apply the bar code sticker to the sample bottle/container, submit your sample information online and ship the sample in to the laboratory nearest you for processing and testing.

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Published September 17, 2019

Tips for Understanding Coolant Component Types

POLARIS Laboratories® has over 32 component types to select from for samples pulled from the cooling system. This can become overwhelming. Why are there so many options when the sample is pulled from the cooling system? The reason there are so many options is because a coolant component type represents:

  • The type of inhibitor packaged used for cavitation protection
  • The type of glycol
  • If the sample is new, a concentrate or in-service
8 Common Formulations

There are at least eight common formulations to select from. Once the formulation is determined, the base glycol will need to be selected. After the formulation and glycol base are selected, there are three options to select from to determine if the sample is a baseline or in-service. This is why there are so many options when it comes to selecting the appropriate coolant component type.

The antifreeze formulation can be provided by the Coolant Manufacturer. Anyone submitting samples, purchasing and maintaining cooling systems should know the type of antifreeze utilized in their fleet. The antifreeze information will help indicate if the coolant formulation meets OEM specifications. OEMs specifications will help regulate what formulation is compatible with equipment, seals and hoses. New, advanced equipment technologies and a competitive coolant market will also help drive the different combination of coolant inhibitors being utilized. A mixed OEM fleet may require different antifreeze formulations on-site to meet specifications or a single antifreeze formulation may be acceptable for all OEMs in the fleet.

Selecting the Correct Formulation

Selecting an accurate formulation of antifreeze for the equipment is important. If antifreeze information is unknown and submitted to the laboratory for testing, we default to consider it a conventional ethylene glycol. If the test package evaluates all possible inhibitors we test for, we will be able to determine what type of antifreeze formulation may be in the system. The coolant component type will determine how the results are analyzed and what recommendations are applied on the final report.

To help understand component types and learn the steps for how to select the correct coolant component type, view our Technical Bulletin, Selecting Coolant Component Types.



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Published July 9, 2019

5 Reasons You Need to be Testing Your Coolant

40 to 50 percent of preventable premature engine failures can be traced back to problems in the cooling system

The majority of those failures are due to issues in the cooling system that can be identified early with coolant sampling

The Importance of Adding Coolant Testing into Your Program

Have you lost an engine and wish you could have caught the problem before the point of no return? Or better yet, what if you could determine the root cause all together? Adding coolant testing to your existing program can do exactly that.

Only monitoring the lubricant provides a limited view of a much bigger picture.

Research has found that when physicians take a whole body approach, their patients heal faster, have a higher success rate, and have a more favorable response to a prescribed medication or therapy. In thinking about our equipment, we should take a similar approach. If you are not testing your coolant, you are ignoring half the patient and half the problems.

As engine metallurgy and design have become more advanced and the demand for increased fuel efficiency and emission’s, engine operating temperatures have increased more than 40 degrees Fahrenheit in the last 50 years. This puts a greater emphasis on maintaining the thermal loads placed on the modern cooling systems.

Some common issues that can be detected and addressed with coolant testing include:

1. Identifying incorrect glycol concentration

There are many causes for the glycol concentration to not be at the proper ratio. Some of the common causes include system top offs with water or coolant concentrate, loss of water due to boil off from a defective pressure cap, and/or flush water left in the system. When glycol concentration is not at the proper ratio per OEM specification problems occur including coolant and engine block freezing, seal damage, and/or overheating. This reduces the life of the lubricant and may cause premature engine failure.

2. Are your pH levels out of specification?

Monitoring the coolant pH levels will indicate early concerns within the cooling system. An engine coolant’s acceptable pH level varies depending upon the coolant formulation. Issues that may arise when pH is out of specification include corrosion of iron components and other metals which often results in pitting of engine liners. Also, corrosives will attack the EGR coolers, or any other cooler in the system. The problem is exacerbated when corrosion protection inhibitors drop out of solution which causes plugging and inadequate coolant flow. When coolant cannot properly circulate, heat cannot be removed efficiently from the engine and the lubricant degrades more quickly resulting in shorter drain intervals.

3. Inadequate corrosion protection inhibitors

The purpose of corrosion protection inhibitors are to maintain pH, prevent foaming and prevent internal metal surfaces from corroding. When corrosion exists in the cooling system heat will not be efficiently removed. Additionally, a corrosive environment will attack most solder joints causing holes and leaks in the system. These leaks will in themselves cause secondary issues including internal coolant boiling, contamination, and adverse chemical reactions.

4. Find sources of contamination

There are many possible sources of contamination which cause damage to the cooling system and ultimately the engine. For our purposes, we will focus on the most preventable source: water, which is used to dilute coolant concentrate or top-off the system. Using water that does not meet ASTM and/or OEM manufacturer’s specifications will increase scale formation and corrosion potential within the cooling system. Even ‘clean’ tap water may contain magnesium, calcium, sulfate or chloride in levels that are harmful for the equipment. Scale forms where the greatest amount of heat transfer is needed and acts as an insulator resulting in overheating and engine damage.

If you want to learn more about adding water to your cooling system, check out our video here.

5. Detect early failure

Coolant testing can indicate combustion gas leaks, air leaks, glycol degradation, electrical issues and contaminants. Each issue will cause chemical reactions within the cooling system, resulting in failure. With early detection, scheduled down time for repairs can be made. Correcting the issue will help prevent complete engine failure or unexpected downtime.

Corrosion occurs at a slower rate than engine wear. This is why engine failures occur more frequently but are often traced back to issues within the cooling system. The cooling system must be able to circulate coolant, remove heat from the system and dissipate the heat in order to function correctly. When the cooling system is not able to circulate or remove the heat effectively, we will see reduced life of the lubricant, increased engine wear, and/or issues with system components, which often result in premature engine failure.

Coolant Test Descriptions

See all possible coolant testing, how the testing is performed and what it can tell you about your system:

Basic and Advanced Testing

Test all fluids in your equipment!

Testing all fluids within the equipment by utilizing an effective fluid analysis program will help reduce unexpected down times and/or equipment replacements – resulting in an increase return of investment (ROI).

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Published April 16, 2019

Cooling System Do’s and Don’ts

40% of engine failures can be attributed to issues within the cooling system. Knowing the do’s and don’ts for maintaining your cooling system will help protect your equipment, increase reliability and avoid failure. Here’s few things to do and a few things not to do.


  • Use a water that meets specifications
    • This includes water being used for top offs, mixing a concentrate and if you are unable to remove the majority of the flush water.
    • Water that meets specifications will not add contaminates to cooling system and will help maintain fluid properties.
  • Use the same coolant formulation for maintenance adjustments
    • If you are unable to use the same coolant in the cooling system (this is recommended), then select a coolant that has similar corrosion protection inhibitors (this will maintain the inhibitor levels for adequate corrosion protection)
  • Test your engine coolant and observe fluid at every PM
    • Every engine sample should have at least one coolant sample tested by the laboratory to ensure equipment health and fluid properties are adequate
    • Catching issues early will stop further corrosion or potential for corrosion by proactively correcting the issues found before catastrophic failure occurs
  • Ensure the correct coolant testing is included in your test package
    • Testing all inhibitors in the formulation will help determine if the corrosion protection levels are adequate or not
    • Advanced testing will help determine if degradation acids are present, identify mechanical issues and determine if the system was contaminated with sulfate and/or chloride
    • Using the right test package will provide the best recommendations and protection for your equipment

Do not:

  • Use any type of water to mix with antifreeze
    • This includes top offs, diluting a concentration or leaving excessive amounts of flush water in the system
    • Using hard water that does not meet specifications, will cause scaling of the system components resulting in loss of heat transfer abilities of the cooling system
  • Mix different coolant corrosion protection formulations
    • Be aware, if you mix an organic formulation with a conventional formulation, some OEMs or coolant manufacturers will state the coolant now must be treated as a conventional antifreeze
    • Some OEMs and coolant manufacturers may also only recommend to change out the coolant if mixed. It’s important to know what recommendations for mixing are for you equipment
    • Mixing formulations will hinder corrosion protection levels and could cause inhibitor drop out, leaving the system vulnerable for corrosion. Concerns of incompatibility between inhibitors can be concerning for the equipment health, too.
  • Put coolant in and forget about the cooling system
    • The most preventable engine failure is not maintaining the cooling system. The cooling system should circulate, absorb heat and dissipate heat from the engine. If issues within the cooling system hinder the removal of heat from the engine then equipment issues and eventually engine failure will occur
  • Simply choose to just test the cooling system
    • Not understanding the proper testing needed for the coolant formulation may not provide the whole picture of corrosion protection levels, equipment health and contamination that may be present in the cooling system
    • These can lead to premature engine failures if the cooling system is not being properly maintained

These simple do’s and don’ts are some of the ways to maintain your cooling system from premature engine failures. The cooling system is part of the overall health of your equipment and should not be ignored.

If you aren’t sure what coolant testing is best for your equipment, reach out to us for guidance and explanation. We’re here to answer your questions – and help you save your equipment!

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Published  February 19, 2019

Extended Life Coolant: Why You Should Monitor Your Corrosion Inhibitors

Extended Life Coolant formulations contain organic acid inhibitors for corrosion protection similar to how conventional formulations use inorganic inhibitors. With extended life coolants becoming more popular testing, the organic acid inhibitors can be trickier in the field and require additional testing in the laboratory than what the conventional formulation would have used. For conventional formulations, monitoring nitrite and/or molybdenum was the main way to determine if corrosion protection levels were adequate or not. Now with all different possible organic inhibitors used in extended life coolants, the fluid may or may not contain inorganic inhibitors, nitrite and/or molybdenum, with the addition of organic inhibitors. Some may contain only organic inhibitors in the formulation.

Organic Acid Inhibitors

Not all extended life coolants are applicable for testing on all test strips used to determine organic levels. The test strip testing may only work on certain organic formulations because the strip is looking for a certain organic acid(s) present which may or may not be present in the formulation in use. Some of the more common organic acid inhibitors found are Benzoic Acid, Sebacic Acid and 2-Ethylhexanoic Acid for iron and aluminum protection. Azoles that are commonly used are Benzotriazole (BZT), Tolyltriazole (TTZ) and Mercaptobenzothiazole (MBT) for copper and brass protection. Coolant manufacturers might not use all of these inhibitors in their formulations which is why laboratory testing is beneficial in determining the type of inhibitors present in the coolant formulation.

High Performance Liquid Chromatography (HPLC)

In the laboratory, the only testing that can report in parts per million the organic acids (carboxylic acids) is with the High Performance Liquid Chromatography (HPLC) testing. The HPLC will report the organic acids present in the formulation and determine if the levels are adequate for corrosion protection. The testing can indicate if mixing of coolant formulation has occurred as well. To determine if mixing occurred, make sure the laboratory testing will include the testing of both the inorganic and organic inhibitors when submitted to the laboratory. If the coolant formulation is unknown it is important to include testing for both inorganic and organic inhibitors as well. If mixing did occur already, then testing will show the current level of inhibitors and help determine if levels are adequate for corrosion protection. Receiving testing that includes identification of all types of inhibitors will be the only way to help determine the type of inhibitors present currently in the system and how to maintain the fluid.

Why Add HPLC to Your Program?

Adding this testing to your current test package will help to indicate if someone has topped off with a different coolant formulation which can cause dilution of the organic acids that protect the metal in your engine or if the current fluid inhibitors are still adequate for corrosion protection. If the organic acid inhibitors are low cavitation, pitting and premature failure can occur. Overall, HPLC testing will help to ensure you achieve longevity with your Extended Life Coolant and engine. The Technical Bulletin, Benefits Gained from High Performance Liquid Chromatography Testing, will provide additional information on the benefits of HPLC testing and explain how the HPLC instrument operates.   

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Published July 10, 2018

Summer Heat Got You Down?

Cooling systems are already burdened with high operating temperatures, and summertime heat can take its toll on your equipment. In order to continuously improve your system’s life and maintain effectiveness, proper cooling system maintenance is vital.

So, what can you do to monitor and identify overheating issues that can lead to catastrophic failure, loss of productivity and a decrease in ROI? Routinely test your coolant – especially during the hot summer months. Read more in our technical bulletin.

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Published June 12, 2018

Can Your Equipment “Weather” the Cold Temperatures?

Dropping Temperatures Equals a Drop in Health

Our winters in Canada, and those in other countries will agree, are often a time of increased health risks. As temperatures drop and winter sets in, so do a whole host of circulating bacteria and viruses. A virus or illness usually starts with a trip to the doctor to assess the symptoms and typically, the doctor uses both a physical exam and potential blood tests to determine how to restore our health and get us back on our feet.

Cure Your Suffering Equipment

Similar to the human body, another winter phenomenon involving cold temperatures is the health of the equipment you use to keep your business running. Mechanical problems or symptoms often arise during the cold temperatures and can cause your equipment to suffer. Similar to the steps the doctor takes, analyzing the critical fluid inside the machine allows you to understand the causes of the problems. Fluid analysis can also allow you to see what actions need to be taken in order for the equipment to get back on it’s feet and be able to “weather” future cold temperatures.

A Prescription for Coolant Analysis

Coolant analysis is one area that is often undervalued or overlooked. But, coolant analysis goes well beyond checking the freeze protection offered by the coolant in cold temperatures. In fact, more than 40% of engine failures are caused by issues that can be traced to the cooling system, the coolant itself holds clues that appear long before any imminent danger. Coolant analysis can shed light on developing problems caused by:

  • Cavitation corrosion
  • Leaking combustion gases
  • Breakdown of the coolant chemicals
  • Overheating
  • Electrical ground problems

A Clean Bill of Health

It’s easy to see that sampling coolant isn’t just a winter activity. But, just like that trip to the doctor when the sniffles set in, sometimes the best course of action is to look within and proactively, to understand what we’re experiencing with our machine health and to begin to save your equipment, before a failure happens.

Let us prove how POLARIS Laboratories® can provide these same benefits to your equipment health.


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Published January 30, 2018

Out With The Old and In With Advanced Coolant Testing

“Out with the old and in with the new.” To help start 2018 new and free of problems – and engine failure – make sure your cooling system is operating correctly with advanced coolant testing.

Prevent Engine Failures

Approximately 50 percent of preventable engine failures can be traced back to problems in the cooling system. Advanced coolant testing can be used not only when trying to detect the root cause of cooling system issues, but can be added to testing anytime to help make sure the cooling system is working correctly before issues arise. With regularly performing advanced coolant testing on the cooling system early, concerns can be addressed before a snowball effect of corrosion, loss of heat transfer and ultimately, engine failure occurs.

Ion Chromatography

Advanced coolant testing will involve Ion Chromatography, or “IC” testing. The IC test detects degradation acids that can form naturally as the glycol breaks down with age or may form due to issues with the cooling system. The IC will also detect contaminates, chloride and sulfate that may have entered the system without you knowing of an issue. Contaminates found by IC testing can form acids and create corrosion to the system rapidly. Once degradation acids form, the glycol will continue to break down, creating more and more acids that can cause severe corrosion of the cooling system components and will lead to engine failures. Two of the most common issues seen on the engine side due to issues with the cooling system include exhaust gas recirculation (EGR) failures and oxidized oil, shortening the life of the oil and increasing wear contamination.

See Trends

Performing advanced coolant testing regularly will also let you see trending results. This will help indicate possible issues such as air leaks, combustion gas leaks, hot spots or even electrical ground issues. With the ability to trend results, an increase in contaminates or degradation acids would indicate an issue or issues are occurring in the system.

For more information, view our Technical Bulletin and reach out to your laboratory to have advanced coolant testing added to your coolant sample.

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Published January 2, 2018

The Underwater Test: Why You Should Test Your Equipment After a Flood

Sometimes it’s hard to plan for destructive natural disasters – such as Hurricane Harvey along the Texas and Louisiana Gulf Coast and the subsequent flooding. So, what do you do if your equipment is exposed to the disaster’s effects and flooding?

Based on years of experience in helping companies save their equipment and extend the equipment’s lifecycle, quite simply we recommend taking action.

Flooding can result in water contamination and can cause corrosion and oxidation which can be extremely harmful for your equipment and, in turn, can cause holds in production and loss of business. How will you know if you need to test your equipment’s fluids to see if any damage was caused and determine if potential maintenance is needed?

First, check for signs of water ingression or leaking. Search for answers to key common challenges, such as:

  • Is the high-water mark above the containers?
  • Is dried mud crusted on the container?
  • Are caps, lids and vents still in place?
  • Are desiccant filters saturated?

After you check for signs of water ingression, the next steps for testing depend on the type of fluid:

Oils and Lubricants

Check the fluid itself for signs of water contamination. A milky appearance indicates the oil additives have emulsified as much water as they could, and there is likely more dissolved in the fluid. An oil analysis test from POLARIS Laboratories® includes a water test, and elemental analysis can identify dirt contamination from mud or salt from sea water.


Pressure caps on coolant containers typically prevent floodwaters from entering cooling systems. However, it is still worth the time to perform a field test using a refractometer or paper test strip to determine if the glycol/water ratio is still in balance. If you suspect contamination, a coolant analysis test from POLARIS Laboratories® will determine if the external water and dirt requires the cooling system to be drained and/or flushed.

Bulk Tanks

Bulk tanks typically have water drain-off ports to remove free water that settles to the bottom of the tank, but the fluids should be checked for water as well as using the techniques above. A “thief bomb” or “bacon bomb” may be needed to collect the sample. Diesel fuel and new lubricant testing from POLARIS Laboratories® will determine if the fluid quality is adequate for future use.

It’s crucial for any contaminated oils, coolants or diesel fuel to go through analysis testing when flooding occurs. Testing can prevent future issues from arising and can help determine what equipment maintenance is needed to resume work.

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Published September 6, 2017