Originally Posted by PatsSS
Should you continue running DOT3 on the clutch side, or switch to DOT4 like the cap says?
If you never race your car, you'll be fine if you keep your DOT3 fluid.
However, DOT4 can be mixed with DOT3 and is definitely not harmful to the car. The following general info may help you decide whether to upgrade or not:
Polyglycol Based DOT3 - Color - Amber | One of the most common brake fluids found on the market used for cars designed during the late 80s period and beyond. DOT3 absorbs moisture the quickest and has the lowest boiling point and should only strictly be for road use.
Polyglycol Based DOT4 - Color - Amber | The benchmark specifications by the majority of car manufacturers. DOT4 is designed to absorb moisture slower than DOT3 and has a higher boiling point. This is both suitable for road use and track work. Using racing specific DOT4 refined brake fluids will increase higher temperature tolerance particularly under hard braking conditions.
Always take care when handling brake fluid as it will corrode body paint work in a matter of seconds if contact is made. Should accidental spills or drips happen, immediately flush affected surface area with high spraying water and wipe off area.
With it's higher boiling point and lower rate of moisture absorbance, I would upgrade the brake/clutch fluid to DOT4 even if I didn't race my car.
I recently attended a High Performance Driving school for a weekend, so I upgraded to DOT4.
Unfortunately, it was before I had separated the brake and clutch reservoirs.