Color of Brake Fluid - DOT 3


It is written in the manual of my car that the brake fluid must be DOT3. The time interval the car’s manufacturer recommend for brake fluid replacement is written 60000 km or 60 months with DOT 3.
The life of my car is 2.5 years and 5500 km.
As you know, the color of the DOT 3 brake oil is light yellow.
The brake fluid in my car is now light(clear) green/blue. Why has the color of the brake oil changed? why brake fluid turns light green? I have not used the car much. Only 5500 km.
Should I change the entire brake fluid?

Thanks in advance



How often does your car require the brake fluid to be changed? If it’s every three years, as on many cars, it seems sensible to do it now for peace of mind.


I replaced brake fluid on my dot-3 requiring truck recently, used synthetic version of dot 3. Noticed it was pretty much clear, very little color. What replacement time interval does the car’s manufacturer recommend for brake fluid? If no manufacturer recommendation, folks here seem to think every 2-3 years. Never noticed brake fluid turn green myself, but explanation above seems a likely cause, hydraulic fittings contain copper, oxides of which are green. It’s possible my cars’ brake fluid has turned green before, but never noticed b/c then it wasn’t synthetic so had a color which masked the green.

Thank you for reply , I edited my question and insert a photo. The time interval the car’s manufacturer recommend for brake fluid replacement is written 60000 km or 60 months with DOT 3.

I edited my question and insert a photo. Please see. Thanks

@Shervan360, I can’t see the color of the brake fluid well. The shadows inside the reservoir make it difficult to see colors inside. If you have a turkey baster or even about 6” of clear plastic tubing you can pull up fluid into the tube and take a picture. As long as you keep your thumb over the dry end of the tubing the fluid will stay inside. You could also put the fluid you suck out into a white plastic bowl and take a photo.

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That fluid looks old and grungy to me.
Dissolved copper would be green.
Time for a full change/bleed.
I do it at least every 3 years regardless of what the manual says.

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First thing I would do is get a sample of the brake fluid in a clean clear glass container. Hard to tell the color looking into the reservoir.

But you’re near 3 years, might as well have a good shop replace the fluid. On new cars they need to know what they’re doing, the ABS systems make it complicated.

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Never hurts to do maintenance earlier than required. On my car, purchased new 2020 model in May 2021. I did my first oil change @ 2000 miles, next change @ 5000, then @ 10000, next will be at 15000, will likely do brake fluid then.


Another idea I’ve used for that purpose, disposable plastic drinking straw.

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Certainly, green fluid can be the result of copper dissolving into the fluid. Just to cover all the bases, I have another possibility- did anyone top off the fluid? Is it possible they mixed fluid manufacturers? DOT 3 comes in some different colors:

What colors can brake fluid be?

Different Brake Fluid Types

  • DOT 3 Brake fluid: Typically in clear, yellow, blue, and red shades.
  • DOT 4 Brake fluid: Typically in light yellow or crimson red shades.
  • DOT 5 Brake fluid: Typically in purple shades.
  • DOT 5.1 Brake fluid: Typically in clear, yellow, and blue shades.

Yellow and Blue mixed makes Green…


You have DOT 4 fluid.

Thank you, Written in the manual of my car that the brake fluid must be DOT3. In my country, All DOT3 brake fluid are yellow.
When I get car, the color of brake fluid was yellow.

Just have the brake system flushed next time you take it in for service. Be done with it and ease your mind.
When you said age of car is 2.5 years, I suspect you mean you bought it new 2.5 years ago, manufacture date could be over three years old.

Hi Shervan:
You don’t state what vehicle and year you have, but in an older thread you said you had a Peugeot 405.

I just did a quick search for brake fluid requirements on various years of Peugeot 405 vehicles. All of them specified DOT 4.

Where are you seeing a spec for DOT 3 for your car?
What is your make, model, and year?