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Hello.

A quick question: Can I mix DOT3 and DOT4+ fluids together? I've tried to google and I've tried to search but I haven't found a simple answer. I'm doing some maintenance work with the brakes and might need to add some fluid so I was just thinking if I could use the fluid we have at work.

Thanks.

as long as your brake system uses at least dot 3 you'll be fine...if you read the bottle on dot4+ it says that it "meeets or exceeds the standards of dot 3"

Yeah. I was just wondering if there will be any sort of chemical reaction or something if DOT3 and DOT4+ have too different ingridients. But it is safe to top the reservoir with DOT4+ with excisting DOT3 in the system?

Just make sure the DOT4 says it's compatable with DOT3 fluid... usually it'll say it on the bottle.

You can use
DOT 3
DOT 4 or
DOT 5.1

DO NOT USE
DOT 5 or other silicone fluids. NOT Compatible.

As far as mixing several DOT 4 fluids are their DOT 3 fluid as well. Sort of like same basic fluid with higher specs.

I've always heard NOT to mix any two fluids. The brake system works with DOT 4, but mixing them isnt a great idea. If necessary as a temporary fix, no worries, but I would suggest sticking with one or the other.

Thanks for the info guys. I didn't lose too much fluid so I just topped it of with DOT4+ and so far no problems. Once I save enogh money I'll still probably take the car to dealership for a fluid change.

Most of the fluids are very close. Would not worry about brands so much. Heck Valvoline and Castrol make a fluid that is both 3 and 4 now what??? Use Dot 4 stuff in Dot 4 Cars. Heck use it in DOT 3 cars too. Just not 3 in a 4 car.