By on August 19, 2013


This past Friday, Jack reported on Continental’s decision to remove its ATE Super Blue brake fluid from the market, citing its non-compliance with federal motor vehicle safety standards. Apparently, Super Blue ran afoul of regulations regarding the coloration of brake fluid in motor vehicles. It’s not clear exactly what led Continental to recall the product now after years on the market, but it’s obvious why: blue brake fluid is a no-go according to American regulators. As Jack pointed out, this apparent government overreach has cost consumers another choice that amateur racers in particular found useful. Commenters on that story debated the relative merits of regulating automotive fluid colors, in particular brake fluid. So just how regulated are fluid colors anyway, and do those regulations help or hurt consumers overall?

Federal Motor Vehicle Safety Standard 116 is the part of the NHTSA’s safety code that outlines minimum requirements for brake fluid.  Section 5.1.14 specifies color requirements for brake fluid. DOT 3, 4, and 5.1 (the normal glycol-based fluids in most modern cars) must be colorless to amber. High-performance DOT 5 silicone-based fluid must be purple, and mineral oil fluid for other hydraulic systems must be green. These standards were first promulgated in the early Seventies as part of the general package of regulations then coming into force on the auto market. Before the feds stepped in, many individual states had already begun to regulate brake fluid, rightly sensing its safety implications. Setting minimum requirements for brake fluid’s performance seems like a completely fair piece of regulation that few enthusiasts or regular consumers would disagree with. Still, it’s not immediately apparent why regulators felt it necessary to specify a color range for the fluid. Some commenters mentioned that the intent might have been to make a clear distinction between brake fluid and other under-hood liquids. In the early Seventies, when fluid colors were less diverse, that made sense. However, more recent developments in fluid coloration mean that regulators have fallen short of their goal.


It turns out that brake fluid is the only automotive fluid whose color is explicitly regulated, at least on a federal level. A long search through the NHTSA’s standards didn’t turn up any evidence that antifreeze, automatic transmission fluid, oil, windshield washer spray, power steering fluid, or any other kind of liquid is explicitly regulated by color. And a quick trip to O’Reilly or a Google search will reveal that previously mundane fluids are now available in a rainbow of colors. It seems that manufacturer consensus, rather than any specific regulation, is what led to widespread usage of specific colors for fluids such as antifreeze and ATF in the past. The diversification of technology in particular is driving the use of a much wider color palette for these fluids. This bulletin from an industry trade group known as the Filter Manufacturer’s Council outlines the shift away from usage of a single color (bright green) by antifreeze makers. Red, yellow, pink, orange, and blue are some of colors that antifreeze is now available in. And as the bulletin states, no color corresponds to any particular type.

CVT - editable2009


Other kinds of fluids are increasingly available in a variety of colors. The widespread introduction of CVT’s has brought on a new wave of color choices for transmission fluid. Windshield washer fluid comes in many different types. There doesn’t seem to be any favored choice for power steering fluid, with manufacturers using a wide variety of tints.  Regular motor oil and gasoline both seem to be sticking with their typical light brown and yellowish hues for the time being. The carboniferous chemical content of oil may limit what manufacturers can do to change the color of those particular fluids. Of course, that hasn’t stopped the makers of full synthetic oil from diversifying their color choices. Who doesn’t want to slather all their important mechanical parts in shades of deep purple?  The net result is that brake fluid is no longer distinct in color from many other under-hood fluids. Motor oil is just as likely to be amber, as are many others. Even completely clear fluid wouldn’t be different from some coolants and windshield washer sprays. The utility of regulating brake fluid color has been limited by a market that has grown up unregulated around it.  

So where does all of this diversification leave the consumer? It means that for every fluid except brake fluid, there’s a wide variety of choices to fit whatever possible situation might arise. Jack pointed out the usefulness of Super Blue for ensuring complete flushes of braking systems. Using different colored fluids in other vehicle systems could offer the same benefits. In addition, leaving color choices open-ended means that manufacturers are less technologically constrained in their development of better fluids. If a company develops a new and better kind of coolant but can only manufacture it in hot pink, they needn’t worry about the long arm of the law cracking down on account of the color. On the negative side, the wildly proliferating choice in color can be bewildering to consumers and even to seasoned professionals. The increasing crossover of colors between different types of fluids will inevitably lead to more mistakes. It also makes it harder to identify the source of leaks and other kinds of mechanical issues. In the past, red or green stains on the ground were easy to trace. Nowadays, it could be a fluid leak from any number of sources. As makers are increasingly eschewing the use of fluid dipsticks for sensors and a “take it to the dealer” mentality, this spells increased frustration for do-it-yourselfers.           

 Even so, I find that the pros of fluid color diversification outweigh the cons, from both an enthusiast and a regular consumer standpoint. Fewer restraints on development benefit everybody, because it encourages manufacturers to seek out new markets and better ways of doing things. As long as minimum safety standards are met, the risk to the consumer is minimized. It would be one thing if Super Blue didn’t meet minimum standards for performance, but that isn’t the case. Super Blue got yanked from the market because of a well-intentioned but outdated piece of regulation that no longer serves the best interest of consumers. The only real way to keep the regulatory dream of standardized fluid colors alive at this point would be a sweeping crackdown on different-colored fluids across the market. That would hurt both manufacturers and consumers in the short run, and it might artificially limit technological development in the future. Given the current state of affairs, deregulating the color of brake fluid is a win for both manufacturers and consumers.


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25 Comments on “Keep Color Choices Fluid...”

  • avatar

    As I pointed out in the comments on original ATE Super Blue article, the issue was that the fluid claimed to meet DOT 4 specs, and it didn’t. That doesn’t mean the fluid will be be permanently banned; they simply cannot have packages on the shelf claiming to be DOT-4 compliant. A simple label change is enough to get it back in stores. You can buy non-DOT stuff for “non-street-use” All. The. Time., I don’t think brake fluid will be any different.

    I think the reason it’s only brake fluid is regulated is because screwing up your other fluids doesn’t not cause a swift and fiery death, which blown brake seals can.

    • 0 avatar

      Blue brake fluid would confuse the fast-food-mechanic-want-to-be duuuuudes at the quicky oil change place enough for them to push windshield washer fluid into the brake reservoir….

      • 0 avatar

        IMO, any car nerd who uses ATE Super Blue is unlikely to take their car to a fast-food-mechanic-want-to-be.

        • 0 avatar

          Well, sure, but without the standard, it would be a lot more than just Super Blue that was a nonstandard color. And since brake fluid, unlike antifreeze, is generally sold in an opaque container, you wouldn’t know what color the fluid was until you bought it.

          Color is important for brake fluid: you can loosely judge how badly it needs to be changed based on how discolored it is. (The old advice I always heard was something along the lines of “Harp – change in a month; Smithwick’s – change tomorrow; Killian’s – change today; Guinness – change yesterday”). Yes, yes, on a track things are different; this system was set up for your typical commuter driver.

          Dyed brake fluid like Super Blue is certainly appropriate for the track but interferes with this system on a daily driver. And since it was essentially only marketed for track use in the first place it should have been sold as such.

    • 0 avatar

      “I think the reason it’s only brake fluid is regulated is because screwing up your other fluids doesn’t not cause a swift and fiery death, which blown brake seals can.”


      I don’t have a problem with this regulation. What if a mfr decided to produce black brake fluid? Then you couldn’t even tell if it was dirty; clear to amber makes this check easiest, and purple DOT 5 tells you if it’s physically incompatible with your system. I don’t see a problem here.

      Deregulating brake fluid color helps nobody, but potentially risks much.

      • 0 avatar

        I agree with all of the above RE: the purpose of the amber colour for condition and need for segregation of fluids for lay people.

        For many of the specialty fluids in new cars too it has the benefit of distinguishing specialty fluids from the generic ones that previously did the same job — for example the emerald green GM oil the autotrack transfer cases that was no doubt that colour to prevent people from simply filling them up with generic ATF.

      • 0 avatar

        “What if a mfr decided to produce black brake fluid?”

        Nobody’d buy it and they’d stop?

        • 0 avatar

          Except then, as a practical matter, you’d never know what the hell color the cheapo store brand stuff is until you bought it and opened the package.

          Perhaps instead we could have some standards body standardize the color, as well as a number of other important properties like viscosity, corrosivity, stability, boiling point, oxidization rate, and so forth, and then you would only put this standards body’s mark on the package if the fluid all of these requirements, so the customer wouldn’t need to independently verify each of them. There’s an idea.

  • avatar


  • avatar

    I’ve got a tub of Citgo marine(waterproof) wheel bearing grease. The grease is a very appealing shade of blue, looks just like blueberry jam…..tastes OK if you mix enough sugar in it.

  • avatar

    This whole article was superfluous for the simple matter that the few thousand amateur racers who use it to alternate flushings amount to a tiny part of the market and as others have stated it could be perfectly sellable for track use where the claimed benefit is used.

    The tirade just sounds like whining from an anti-regulatory view that tries to pull a generalization from what was a well intended gesture that was discontinued without reversing the original decisions.

  • avatar

    “The net result is that brake fluid is no longer distinct in color from many other under-hood fluids.”

    But it never was, so this statement is in error.
    Anyhow, the whole issue of colored fluids seems to ignore the fact that fluids come in labelled bottles. So, if you are a literate fluids buyer, you are good to go…?

    • 0 avatar

      Apparently it’s no longer safe to presume literacy. Next requirement will be a uniform system of large pictographs that will be mandated to appear on containers. Welcome to Idiocracy.

    • 0 avatar

      I think the color issue is more about working on the car later – perhaps when you didn’t put the fluids in.

      “Hey, there’s red stuff under the car. What’s leaking?”

      (And assume, of course, that it’s a slow leak, so you can’t see a stream … and so that driving will spread the fluid around underneath a bit. [Ask me how I know this happens.])

      There *might* – I am willing to entertain the argument – be some utility in being able to say “red means ATF, so it’s the transmission”, might there not?

      I don’t know that that justifies any old *arbitrary* rule, or the requirement that “brake fluid must, must, must be amber unless it’s DOT-4”, but color coding certainly can have real value in automotive maintenance.

      (Caveats above about not being able to tell how used up it is by color naturally apply to anyone mad enough to try selling opaque black fluid. But the market will fix that one rapidly enough on its own.)

  • avatar

    Actually an add-in dye would make flushing the system a lot more positive; if something along those lines was available I would try it.

  • avatar
    Big Al from Oz

    The servicings we perform include flushes, air bleeds etc.

    We have to use capacity as a measure, not colour. The only time we use color is when fault finding and inspection. So some simple arithmetic will resolve your problem of knowing when the system is flushed.

    Patch testing of hydraulic systems also is a better indicator of the fluids performance and quality.

    I think a different and possibly better approach will give the best possible performance and outcome of any hydraulic system.

    Contaminants and heat kill hydraulics.

  • avatar

    I usually don’t pay too much attention to what colour the fluid is when it leaks out- I go by taste and smell however Prestone sells brake fluid and anti freeze in identical containers- need I say more

  • avatar

    I for one welcome the efforts of the government to protect our precious automotive and bodily fluids….

  • avatar

    My anti freeze is a milky grey color. I am going to call Congress and demand they remedy this!

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