I'm about to replace the brake fluid in my '93 Accord. The manual says to use either DOT 3 orOTot 4 - to look at the master cylinder cap to determine which. Looking at the cap shows both DOT 3 and DOT 4 are on it. I have no idea which fluid was used in the system originally. I'm the second owner and the car has ~205k miles.

If I use DOT 4 and the OEM was DOT 3 will it cause any harm? Which type fluid should I use, and why?

TIA

 

Dot 3 and Dot 4 are very compatible and almost only differ by the operating temperature range
The Dot 4 having a higher temperature range.

 

Thanks!

 

dont worry,they both will work fine.