Frequently Asked Questions

An antifreeze/coolant (“coolant”) provides 3 critical functions in a cooling system: 1) Maintain optimum operating temperature, 2) prevent freeze-up, and 3) protect cooling system metals from corrosion.

An engine creates heat in the process of generating power to move the vehicle.  That heat needs to be removed from the engine and transferred to the surrounding air through the radiator.  Water is a great heat transfer fluid, but has some significant shortcomings.  First, it freezes at +32F, which would be a problem in many areas of the country.  Second, it boils at a relatively low 212F, so the risk of overheating would be high.  And third, it does not provide corrosion protection to the metals in an engine, and can actually cause corrosion to occur.  So, something better is needed.

A typical antifreeze/coolant is a mixture of ethylene glycol and corrosion inhibitors.  In fact, most of a gallon of antifreeze/coolant concentrate is ethylene glycol.  This mixture cannot be used by itself because the freezing point would not be low enough and it would be too viscous (thick) at low temperatures.  Water must be added to create a 50% to 70% mixture of antifreeze/coolant and water to create acceptable freezing point, boiling point and corrosion protection.  Most vehicle manufacturers recommend a 50% mix to help the engine run at optimum conditions.  That’s why all antifreeze/coolant companies offer a 50/50 prediluted product which already contains high-quality water.  The charts below show the freezing and boiling points that result from different antifreeze/coolant and water mixtures.  As the amount of antifreeze/coolant is increased, the boiling point goes up and the freezing point goes down.  To provide even higher protection against boilover, cooling systems are pressurized, typically to 15 psig.  The values in the chart are based on this system pressure.

Finally, an antifreeze/coolant must protect cooling system metals from corrosion over the service live of that coolant.  All coolants marketed in the US must meet the performance requirements of industry standards ASTM D3306 and D6210.  All OWI coolants meet or exceed these standards, and OWI guarantees the performance of their coolants for the service life indicated.

For many years, life was pretty simple when it came to antifreeze/coolants (“coolants”).  Most vehicles in the US were factory-filled with a green conventional formula designed to provide excellent corrosion protection to cast iron and steel engines with copper/brass radiators.  It was based on inorganic additive technology (IAT) corrosion inhibitors.  Over the years, OEMs looked for ways to reduce vehicle weight and started using aluminum components.  That meant the mix of metals in the cooling system was changing and conventional coolants were no longer the best option.  New types of coolants started to be developed to provide protection to systems containing aluminum.

In 1995, the first coolant was launched in the US using a new type of corrosion inhibitor called organic acid technology (OAT).  It was capable of providing good protection for the emerging mix of metals in the system.  This type of coolant quickly became widely used and was marketed by coolant manufacturers as “All Makes/All Models” because it can be used on top of any existing coolant in any vehicle cooling system.

As more foreign vehicle manufacturers started making their vehicles in the US, a range of vehicle-specific coolant formulations began to appear, each designed to protect specific mixes of cooling system metals.  The range of coolant formulations expanded quickly to include what is known as hybrid organic acid technology (HOAT) coolants.  These use both inorganic and organic corrosion inhibitors to provide customized protection.

With all of these new coolants in the market there can be a lot of confusion.  Not only are there different types, but different colors are used to identify the formulas.  This has created a “rainbow” of colored coolants.  To deal with the confusion, PEAK has made it easy for vehicle owners to find the right coolant.  For DIYers driving older vehicles for engines requiring a conventional green coolant, we offer PEAK Green Antifreeze + Coolant.  For those who just want good long-lasting protection, there is PEAK Antifreeze + Coolant for All Vehicles with its extended life technology providing a minimum of 10 years or 300,000 miles of cooling system protection.  And, for more hands-on DIYers who only want OE-level performance, OWI has developed its PEAK Original Equipment Technology Antifreeze + Coolant line, with formulas meeting the specific needs of Asian, European, and North American vehicles.  Each product is formulated with the same technology and color as that of coolant that was in their vehicle right from the factory.

OWI also offers a full line of Fleet Charge and Final Charge brand antifreeze/coolant products for heavy duty applications.  These are specifically designed to protect systems in a wide range of more severe-duty operating conditions.

To find which antifreeze/coolant is right for automobiles, light/medium duty pickup or heavy duty vehicle, check out PEAK’s Product Finder tool or refer to your owner’s manual.

Cooling system failures are the leading cause of mechanical breakdowns [1].  Overheating and other cooling system problems can be the result of many factors such as those listed below.  However, the majority of problems are related to not having enough coolant in the system or the coolant being weak or neglected.  In an OWI survey [2], 60% of vehicles were found to be low or dangerously low on coolant.  A low coolant level can lead to overheating because the coolant is no longer in contact with the hot metal surfaces to absorb the heat and carry it away from the radiator.  It also allows air into the system which can significantly contribute to corrosion.  Weak or neglected coolant is not able to provide the right level of freezing, boiling and corrosion protection.  Major cooling system component manufacturers [3] have found that up to 60% of water pumps and 40% of radiators fail due to poor coolant condition.

Reasons for Cooling System Problems Including Engine Overheating:

The best defense against engine overheating and cooling system damage is good cooling system maintenance.  There are 3 major pieces to this winning strategy:

1. Check the Level in the coolant reservoir every time you open the hood. Top off; if in good condition (for testing the condition see Step 2); as needed. Also inspect cooling system components and make repairs as soon as problems are discovered.  Follow manufacturer’s recommendations for changing hoses, belts and other critical components.  See Question 4 below for checking the level and topping off the system.
2. Test the Condition of the coolant at least twice a year. Once in the beginning of Summer and then again in the beginning of Winter.  It’s important to ensure the corrosion inhibitors are still protecting the cooling system.  Use a test strip, hydrometer (such as the PEAK Antifreeze & Coolant Tester, antifreeze/coolant tester instructions in Question 5), or refractometer to verify adequate freeze-up and boilover protection.
3. Change Your Coolant as outlined in vehicle owner’s manual.  Change intervals may vary from every 2 years/36,000 miles to 10 years/200,000 miles, depending on the manufacturer.  See Question 6 below for changing your coolant.

[1] US Department of Transportation; American Automobile Association

[2] OWI 2017 employee vehicle population survey

[3] Gates Corporation:  Gates I60/R90 Be System Smart Initiative; Spectra Premium radiator failure assessment

Follow the directions below.

CAUTION: NEVER WORK ON A HOT COOLING SYSTEM.  Allow system to cool before removing the pressure cap.  THE UPPER RADIATOR HOSE SHOULD BE COOL AND SOFT WHEN SQUEEZED.

The upper radiator hose will be cool to the touch and soft if the system is sufficiently cool.

Before starting, locate the radiator, coolant overflow reservoir, and pressure cap. The reservoir will be located at a high location on either side of the engine and may be near the radiator or at the back of the engine near the windshield.  The cooling system pressure cap may be on the reservoir if not on the radiator.

If the pressure cap is on the radiator:

1. With the engine off and cool, remove the pressure cap. The coolant level should be at the top of the radiator, ideally flush with the bottom of the pressure cap seat.  If the coolant level is low, go to step 2. Otherwise, securely replace the pressure cap.
2. Add either 50/50 pre-mixed antifreeze/coolant or a 50/50 mix of antifreeze/coolant concentrate and good quality water (e.g., distilled water) until the coolant level reaches the cap seat. Replace the pressure cap.
3. Locate the fill line on the side of the overflow reservoir. If the coolant level is low, remove the reservoir cap and add either 50/50 pre-mixed antifreeze/coolant or a 50/50 mix of antifreeze/coolant concentrate and good quality water until the coolant level reaches the level marked on the tank.  Replace the pressure cap.

If the pressure cap is on the overflow reservoir:

1. With the engine off and cool, locate the fill line on the side of the tank. If the coolant level is low, go to step 2. Otherwise, securely replace the pressure cap.
2. Add either 50/50 pre-mixed antifreeze/coolant or a 50/50 mix of antifreeze/coolant concentrate and good quality water until the coolant level reaches the level marked on the tank. Replace the pressure cap.

Periodically check coolant level and test for freeze and boil protection.

DIRECTIONS

CAUTION: DO NOT REMOVE PRESSURE CAP WHEN ENGINE IS HOT. THE UPPER RADIATOR HOSE SHOULD BE COOL AND SOFT WHEN SQUEEZED.

1. Unscrew the pressure cap on your vehicle’s antifreeze/coolant reservoir or radiator to allow access to the coolant for the test.
2. Take your PEAK Antifreeze/Coolant Tester and squeeze the air out of the device by pressing and holding the black rubber ball at the top of the tester. While squeezing the rubber ball, insert the nozzle into the coolant. After inserting the nozzle, slowly loosen your grip on the black rubber ball to allow the coolant sample to enter the tester, filling it up to the fill mark.
3. Once you have a sufficient coolant sample in the tester, hold it up to any light source so that you can see through the tester. If the coolant sample is discolored (e.g., rusty-brown), or has particles or sediment in it, a complete drain, flush and fill should be performed [insert link for drain, flush & fill directions]. Bubbles may appear soon after collecting the sample. Tap the tester to shake loose any bubbles so the pointer/needle can move freely.
4. One side of the tester displays the freezing point and the other side displays the boiling point, both in Fahrenheit and Celsius. The pointer/needle on the tester will point to a certain temperature reading based on density of the antifreeze/coolant and water mixture.

You can either perform a Drain/Fill or Drain/Flush/Fill. A Drain/Flush/Fill is recommended because it does a better job of removing old coolant and corrosion deposits.  Follow the directions below for each.

DRAIN/FLUSH/FILL

Draining the system may leave a significant amount of old coolant and flush water behind.  Use only antifreeze/coolant CONCENTRATE when performing a drain/flush/fill to ensure the right coolant/water ratio is achieved.

Check vehicle owner’s manual for coolant TYPE, capacity and change interval recommended by vehicles manufacturer. specific cooling system maintenance recommendations.
Note: Before starting, locate the radiator drain valve (if equipped), lower radiator hose and cooling system pressure cap. The cap may be on a remote overflow reservoir if not on the radiator.

DIRECTIONS
CAUTION: DO NOT REMOVE PRESSURE CAP WHEN ENGINE IS HOT. THE RADIATOR HOSE SHOULD BE COOL AND SOFT WHEN SQUEEZED.

1. Remove pressure cap from radiator or overflow reservoir.
2. Drain cooling system by opening radiator drain valve. Disconnect lower radiator hose if there is no drain valve. Collect fluid for proper disposal. If the system has corrosion deposits (the coolant color is typically rusty/brown which is a good indicator that it needs to be replaced) in it, a chemical flush is recommended. Use PEAK Cooling System Cleaner & Flush to ensure maximum cooling system performance. Follow instructions on the bottle.
3. Close radiator drain valve and reconnect radiator hose.
4. Fill with fresh water and replace pressure cap. Start engine and run for 15 minutes with the heater on high. Stop engine and allow to cool.
5. Repeat steps 1 and 2.
6. Close radiator drain valve and reconnect radiator hose.
7. Check owner’s manual for cooling system capacity and recommended antifreeze/coolant concentration. Fill system with enough new antifreeze/coolant to achieve the desired concentration. A 50% to 70% concentration is acceptable. A 50/50 antifreeze/coolant and water mix is recommended to achieve optimum freeze, boil and corrosion protection. Top off the system with water.
8. Remove old coolant from reservoir tank and add a 50% to 70% mixture of antifreeze/coolant concentrate in water to the level marked on the tank.
9. Replace pressure cap and run engine 15 minutes with the heater on high. Stop engine and allow to cool. Check antifreeze/coolant level and freeze protection and add more antifreeze/coolant concentrate or water, as necessary.

Periodically check coolant level and freeze protection.

DRAIN & FILL

Draining the system may leave a significant amount of old coolant behind.  Using antifreeze/coolant concentrate is recommended when performing a drain & fill to ensure the right final concentration is achieved.

Check vehicle owner’s manual for coolant capacity and specific cooling system maintenance recommendations.
Note: Before starting, locate the radiator drain valve (if equipped), lower radiator hose and cooling system pressure cap. The cap may be on a remote overflow reservoir if not on the radiator.

DIRECTIONS

CAUTION: DO NOT REMOVE PRESSURE CAP WHEN ENGINE IS HOT. THE RADIATOR HOSE SHOULD BE COOL AND SOFT WHEN SQUEEZED.

1. Remove pressure cap from radiator or overflow reservoir.
2. Drain cooling system by opening radiator drain valve. Disconnect lower radiator hose if there is no drain valve. Collect fluid for proper disposal. If the system has corrosion deposits in it, a chemical flush is recommended. Use PEAK Cooling System Cleaner & Flush to ensure maximum cooling system performance. Follow instructions on the bottle.
3. Close radiator drain valve and reconnect radiator hose.
4. If using a 50/50 prediluted antifreeze/coolant, fill the radiator up to the bottom of the filler neck. If there is no radiator pressure cap, add the antifreeze/coolant to the pressurized overflow reservoir to the level indicated on the reservoir. If using antifreeze/coolant concentrate, install a 50/50 mix of antifreeze/coolant and water into the radiator up to the bottom of the filler neck, or into the pressurized overflow reservoir to the level indicated on the reservoir.
5. Remove old coolant from reservoir tank and add either 50/50 prediluted antifreeze/coolant or a 50/50 mix of antifreeze/coolant and water to the level marked on the tank.
6. Replace pressure cap and run engine 15 minutes with the heater on high. Stop engine and allow to cool. Check antifreeze/coolant level and freeze protection and add more antifreeze/coolant or water, as necessary.Periodically check coolant level and freeze protection.