What Brake Fluid

[Nick Franks]

What is the highest Dot rating brake fluid that I can use in my 08 GMC 2500hd duramax? Original spec is Dot 3, but wondering if I can use a higher boiling point fluid.

[Black02Silverado]

Yes, you can go to a DOT 4.   I use AMSOIL's. 

[dgstarr63]

GM recommends DOT 3 because it s less hydroscopic than DOT 4.  If you were racing DOT 4 would be a better choice., I will stick with the recommended fluid.

[Formulabruce]

DOT 4.5 is THE Highest you can go. It has a slightly higher boiling point, still synthetic.

 

[davester]

The numbering is confusing, but you can also use 5.1.  BUT, you CANNOT use 5.0

 

https://epicbleedsolutions.com/blogs/faq/whats-the-difference-between-dot-4-and-dot-5-1-brake-fluid#

 

[niomarvin83]

Hello, any DOT 3 will work, brand is irrelevant.
I just flushed mine. Picked up 3qts of synthetic DOT 3 from Autozone at motor trader for $4.50/qt. It's not crazy expensive for good synthetic brake fluid as I sought.

[Grumpy Bear]

I'm with Nick on this one.

 

 

 

This stuff has a higher boiling point, both wet and dry than the threshold spec of a 5.1