Nitrite-Free Coolants on the Rise Due to More Aluminum in Engines
This story appears in the March 13 print edition of Equipment & Maintenance Update, a supplement to Transport Topics.
As manager of technical development for TA and Petro travel centers, Homer Hogg sells a lot of coolant to fleets of all sizes. In 2010, he started seeing something strange: a white residue plugging coolant filters and coating cylinder liners.
“I was receiving calls on a regular basis, and pictures and all kinds of frightening-type scenarios from our technical support center,” he said. “I was getting pictures of coolant filters that were totally restricted from this white residue.”
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It’s because of that residue, and other issues with nitrite-based coolants, that nitrite-free coolants are projected to more than double as a percentage of the market by 2023. But not every fleet is making the switch yet — and some should not.
The issue is rooted in manufacturers light-weighting Class 8 engines by using more aluminum and less steel to improve fuel efficiency and reduce greenhouse-gas emissions.
Coolants with nitrite organic acid technology react with the flux used to braze aluminum parts together. That reaction changes the coolant’s acidity, increasing metal corrosion and leading to undissolved solids and residue that plug filters, coat heat exchangers and cause scale on cylinder liners. This reaction can prevent heat from escaping and cause a localized heat spot, potentially leading to a fuel pre-ignition.
Meanwhile, nitrites deplete rapidly, requiring the addition of supplemental coolant additives. Overuse of nitrites when servicing can lead to pitting and leaks of thin-walled aluminum heat exchangers.
In other words, “Old coolant technology met new truck technology, and the match wasn’t quite right,” said Colin Dilley, vice president of technology for Prestone Products Corp.
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|By Steve Brawner|
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