Dot 5 Brake Fluid or Not?

[997 C4S]

2006 997 C4S 45,000 miles. Is Dot 5 brake fluid (the blue stuff) bad for the seals in this car? Have heard conflicting stories. I change the fluid at the end of summer and in the spring after sitting all winter.

Thanks

[JFP in PA]

Do not use DOT 5 brake fluid, these cars were not designed to use it. Use DOT 4 such as ATE Blue or ATE 200.

[997 C4S]

Well said,

Thanks for the info. Is there a source document I can reference?

Platt

Ne rêvez pas trop petit sinon vous y arriver!

[matt demaria]

This has always been confusing. Dot 5 (purple color) is silicone and does not mix with the other brake fluids. Dot 5.1 is the same as Dot 200 or Dot 4 Super and is all the same.

[JFP in PA]

Originally Posted by 997 C4S

Well said,

Thanks for the info. Is there a source document I can reference?

Platt

Ne rêvez pas trop petit sinon vous y arriver!

Probably the best source is the OEM service manuals (online only via subscription), which spec Dot 4 fluids. DOT 4 cars are not necessarily DOT 5 compatible. We have had a couple customer's try the DOT 5 silicone based fluid, which resulted in multiple seal failures and a very some large repair bills.

[JFP in PA]

Originally Posted by matt demaria

This has always been confusing. Dot 5 (purple color) is silicone and does not mix with the other brake fluids. Dot 5.1 is the same as Dot 200 or Dot 4 Super and is all the same.

And don't forget the SL 6 low viscosity fluids for cars with the ESP stability management electronic braking systems............