Manual Says DOT3, Forum Says DOT 4?
 

Ok, my brake fluid was low, so I put some DOT 3 in just as the manual, and the resivour cap said to do. But in several threads, I have read to use DOT 4. Which is it? Please tell me I did not screw somethin up!!!!

Id say put in dot3 if the manual says so. Any opinion on here might be in light of performance.

It says DOT3 in the manual because that was the best available when it was written. DOT4 is better than DOT3 and perfectly suitable for most cars, including yours.

Dot 4 has a higher boiling point, and is generally a better brake fluid for performance. But it wasnt around when FC's were new.

Whew. Thanks guys. Is it ok to mix the two? Like if I use a syringe to pull out the stuff in the resivour and add the DOT 4, cuz there is still DOT 3 in the lines, is that ok to do?

dot4 is a rating. it meets the dot3 standards, but it exceeds them and reaches a new standard called dot4

I guessed as much. Thanks, I just wanted to be sure. I read a thread that said if you use dot 5 it will ruin the brake system, so I just wanted to be sure.

Amongst other things DOT 4 has a higher boiling pointthan DOT 3, both in its pure state, and after having absorbed a percentage of water ( brake fluid is hygroscopic). They are compatible fluids as far as the seals used in brake and clutch hydraulic systems.
You may see other hydraulic fluids on the shelves BE CAREFUL - there is a DOT 5 which is NOT COMPATIBLE with earlier fluids, and - for christ sakes- DOT 5.1 which is the latest fluid and it IS compatible with DOT 3 and DOT4.
If you use an incompatible fluid you WILL damage the seals in ALL the hydraulic components in your vehicle - this will be VERY VERY expensive to repair (don't ask me how I know this - thankfully it was an old car with a simple hydraulic system - no ABS)

Cool. I will just keep on usin the good ol DOT 3! Thanks Guys!!

5.1 is mixable with 3 and 4 and is compleaty different then 5. 5 is silcon based. 3,4, and 5.1 are not.

If you plan on doing any track work, upgrade to DOT4 or DOT5.1 beforehand.

Well, then, I will upgrade! WOW! SO much info, for such a little question! Thank you soooo much!