Be Really Cool

| May 13, 2002

Managing SCA depletion by maintaining the level in the system is another challenge. In addition to the above variables, every engine runs a different duty cycle. The SCA additives used with all conventional coolants, composed mainly of nitrites and nitrates, will deplete at a rate that depends upon how the engine is used. There is no reliable way to determine how fast the SCAs will break down, or when you should add them, except testing. As David Strauss says, “It’s best to test. The truck owners who test their coolant regularly have the best luck with their cooling system.”

Why? Because too little SCA means the system will corrode or clog, and too much creates that damaging grit.

When using SCAs, it’s best to buy what Strauss terms a “3-way” test kit. This tests the percentage of water versus glycol, the level of SCAs, and the pH. Caterpillar recommends the use of a refractometer-a glass device that reads the level of either type of glycol with light. Some engine makers’ test strips don’t test for pH, but you can have coolant tested through a dealer to check that all-important acidity.

Preserving SCA protection
See your OEM operator’s manual for coolant test intervals, most often 15-20,000 miles, although some suggest longer intervals.

One thing SCAs protect against is acidity. The pH should be between 8.5 and 10.5, says Strauss, but if the protection fails and pH drops below 8 (meaning the coolant has become acidic), it must be replaced.

There are three ways to add SCAs to the system (in addition to starting out with fully-formulated coolant). You can buy SCAs in concentrated form in a jug and just pour them in. Or, you can buy a cooling system filter that adds SCAs as the coolant passes through it.

You can change a filter with a “maintenance” charge of SCAs at recommended intervals-such as every oil change or every other oil change. You can also use a “need-release” type of filter. These use a membrane or special chemistry in the additives to ensure that SCAs only leave the filter and enter the system when the fluid’s SCA level is too low and more are needed. These, typically, have a long change interval in the range of 18-months and 120,000 miles, says Ed Eaton president and chief engineer of Amalgatech. Eaton says “The PowerCool need-release filter, used with Detroit Diesels, automatically adds protective chemistry as it is needed, reducing the concentration of dissolved solids and extending the life of the antifreeze.”

Dave Brisk, business manager coolant and chemical products at Fleetguard, adds that these filters contain a “very fine, synthetic media” that does a better job of getting debris out of the system in addition to adding the chemicals gradually. He agrees with Eaton that such a system allows coolant to last much longer.

With these filters there is much less leftover solid material in the coolant from the SCAs. So instead of having to drain at 200,000-240,000 miles to get that solid stuff out of the system, you can use the coolant for 600,000 or more miles.

Strauss reports that Mack has a maintenance-type filter that has a standard replacement interval that varies from about 30,000 to 50,000 miles, depending upon the duty cycle (hours also figure in). It’s good to generally follow manufacturer’s guidelines when changing these filters. But, you should also test. When adding SCAs out of a container, it’s essential to test.

Follow the directions on the test strip container as to coolant temperature and other details to get a good measurement. Once you get the reading of SCA level, typically something like 800-1,200 parts per million, you need to determine the number of containers of SCAs to add. Follow charts in the OEM maintenance manual as to test levels and how much to add. Change the maintenance filter only if the reading is low enough. If the concentration is extremely low, you will have to change the filter and add a container of SCAs. Always remember to match the size of the filter to the engine’s coolant capacity.

Above all, make sure not to add SCAs both via a maintenance filter and other containers. And, if you are using a need-release filter, don’t change it before it’s time, replace it with the wrong filter, or add SCAs from a bottle by mistake.

Be Really Cool

| May 13, 2002

Managing SCA depletion by maintaining the level in the system is another challenge. In addition to the above variables, every engine runs a different duty cycle. The SCA additives used with all conventional coolants, composed mainly of nitrites and nitrates, will deplete at a rate that depends upon how the engine is used. There is no reliable way to determine how fast the SCAs will break down, or when you should add them, except testing. As David Strauss says, “It’s best to test. The truck owners who test their coolant regularly have the best luck with their cooling system.”

Why? Because too little SCA means the system will corrode or clog, and too much creates that damaging grit.

When using SCAs, it’s best to buy what Strauss terms a “3-way” test kit. This tests the percentage of water versus glycol, the level of SCAs, and the pH. Caterpillar recommends the use of a refractometer-a glass device that reads the level of either type of glycol with light. Some engine makers’ test strips don’t test for pH, but you can have coolant tested through a dealer to check that all-important acidity.

Preserving SCA protection
See your OEM operator’s manual for coolant test intervals, most often 15-20,000 miles, although some suggest longer intervals.

One thing SCAs protect against is acidity. The pH should be between 8.5 and 10.5, says Strauss, but if the protection fails and pH drops below 8 (meaning the coolant has become acidic), it must be replaced.

There are three ways to add SCAs to the system (in addition to starting out with fully-formulated coolant). You can buy SCAs in concentrated form in a jug and just pour them in. Or, you can buy a cooling system filter that adds SCAs as the coolant passes through it.

You can change a filter with a “maintenance” charge of SCAs at recommended intervals-such as every oil change or every other oil change. You can also use a “need-release” type of filter. These use a membrane or special chemistry in the additives to ensure that SCAs only leave the filter and enter the system when the fluid’s SCA level is too low and more are needed. These, typically, have a long change interval in the range of 18-months and 120,000 miles, says Ed Eaton president and chief engineer of Amalgatech. Eaton says “The PowerCool need-release filter, used with Detroit Diesels, automatically adds protective chemistry as it is needed, reducing the concentration of dissolved solids and extending the life of the antifreeze.”

Dave Brisk, business manager coolant and chemical products at Fleetguard, adds that these filters contain a “very fine, synthetic media” that does a better job of getting debris out of the system in addition to adding the chemicals gradually. He agrees with Eaton that such a system allows coolant to last much longer.

With these filters there is much less leftover solid material in the coolant from the SCAs. So instead of having to drain at 200,000-240,000 miles to get that solid stuff out of the system, you can use the coolant for 600,000 or more miles.

Strauss reports that Mack has a maintenance-type filter that has a standard replacement interval that varies from about 30,000 to 50,000 miles, depending upon the duty cycle (hours also figure in). It’s good to generally follow manufacturer’s guidelines when changing these filters. But, you should also test. When adding SCAs out of a container, it’s essential to test.

Follow the directions on the test strip container as to coolant temperature and other details to get a good measurement. Once you get the reading of SCA level, typically something like 800-1,200 parts per million, you need to determine the number of containers of SCAs to add. Follow charts in the OEM maintenance manual as to test levels and how much to add. Change the maintenance filter only if the reading is low enough. If the concentration is extremely low, you will have to change the filter and add a container of SCAs. Always remember to match the size of the filter to the engine’s coolant capacity.

Above all, make sure not to add SCAs both via a maintenance filter and other containers. And, if you are using a need-release filter, don’t change it before it’s time, replace it with the wrong filter, or add SCAs from a bottle by mistake.

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