Dot 3 verses Dot 4 brake fluid

MARTIN MIRITI

MEMBER
2007 NISSAN NOTE
1.5L
4 CYL
2WD
AUTOMATIC
120,000 MILES

Kindly advise if I can use dot 4 brake fluid on my car listed above.
I have not changed it for 6 years now.
The manufacturer recommends use of Dot3 only.

Kindly advise if there is any damage or risk.

Thanks you.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

DOT 3 and 4 are both non silicone based oils so they can be swapped but do not use DOT 5.

There is no need to move from 3 to 4 but if you want to you can. The only difference between the two is DOT 3 has a lower boiling points. Plus DOT 4 absorbs less moisture so you will get a little more life out of it. This means as water gets into brake fluid and it lowers the boiling point, DOT 4 will last longer because it started at a higher temperature.

The reason it says DOT 3 only in the manual is because when they made this vehicle DOT 4 was not out yet but there were other silicone type fluids and they cannot be mixed.

If you are going to do this, I would not top off your DOT 3 with 4. I would flush the system and put in DOT 4 if you want to switch.

Here is a guide on how to do this:

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

Let me know what questions you have. Thanks