2006 Chevrolet Trailblazer DOT3 (replacement fluid)adding?

I have a 2006 Chevrolet Trailblazer it requires DOT3 brake fluid, the only type I see in the stores is 'DOT 3 Synthetic' brake fluid. Will this cause any harm to the seals/o-rings/gaskets and/or master cylinder mixing it with the original?

Or would it be better to get the ACDelco DOT3?

Fixing to replace the brakes and most likely will need to top off/bleed the brakes.


Gold Supporter
Dot 3 is dot 3 I believe.
Check the label of the synthetic stuff. Should say if it can be mixed. IIRC, only Dot 5 can't be mixed with anything else.


Well-Known Member
Words you DON'T want to mix is Silicone & Alcohol based brake fluids (this is the "regular" brake fluid). In days of old all synthetic was only Silicone based (typically DOT 5), but some of the "newer stuff" synthetic doesn't seem to be. If these two are mixed you will be replacing the master cylinder and all calipers in a short period of time (let me tell you how I know :sadcry: -and I thought I had flushed the system out very well before replacing all brake fluid with the silicone brake fluid. Very expensive mistake it was.


Well-Known Member
dot3 is dot3, don't worry if it says "synthetic" on it.

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