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My brake fluid warning light came on and I noticed it is a little low but I'm wondering which fluid to purchase. The manual states DOT3 but the cap DOT4. Should I assume DOT4 and that the manual is incorrect? Or does it even matter because I've already bought a new bottle of DOT3?

2012 with MT.

Thanks.
 

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In my 2013 DCT's manual, it says "DOT4". I checked all 5 versions of the manual on Ford's website for the 2012 and it says DOT3 in all 5 revisions.

However, the main difference of DOT3 and DOT4 is boiling point of the fluid. The DOT3 standard has a lower minimum boiling point requirement then DOT4. Going with a higher quality DOT3 or a DOT4 will give you more tolerance though. DOT4 also handles moisture better. So bottom line, you can probably use either without making any damages to the system, but if I had the choice, I'd go with DOT4.

David.
 

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Strichmädchen & Koks
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DOT 3 & 4 brake fluids are "interchangeable", meaning either can be used without damaging any brake components. However, DOT 4 DOES have a higher boiling point, so the two shouldn't be mixed and you should use whatever your manual (or reservoir cap) says. You CAN mix them without damaging anything, but realize the properties of the fluids will not be as they were originally rated...hence why you should just stick to one.

If you know whats' already in there, use more of that. If you want to change, do a flush. If it calls for DOT 4 it's safer to put DOT 4 as it can handle more heat. If it calls for DOT 3 either will work.
 

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As others have said, use whatever you want. DOT3 and DOT4 are 100% interchangeable, though if you don't flush the old DOT3 out, you will retain most of the characters of that (lower boiling point, more hygroscopic).

DO NOT DO NOT DO NOT DO NOT use DOT5. Repeat after me. DO NOT USE DOT5. Unless you want to find out exactly how much it costs to replace each and every single brake-related component in your vehicle. Protip: It's a lot.
 

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I have the same issue and question CeeBee. Manual says one thing, resevoir cap says another. I don't know what fluid type is in the brake lines now (DOT 3 or 4), but I'm doing a brake job this weekend and will top off with DOT4.
 

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As others have said, use whatever you want. DOT3 and DOT4 are 100% interchangeable, though if you don't flush the old DOT3 out, you will retain most of the characters of that (lower boiling point, more hygroscopic).

DO NOT DO NOT DO NOT DO NOT use DOT5. Repeat after me. DO NOT USE DOT5. Unless you want to find out exactly how much it costs to replace each and every single brake-related component in your vehicle. Protip: It's a lot.
BUT

DOT 5.1 is fine!

Geez the naming convention is awful!!!
 

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Like said above dot 3 & 4 are interchangable. 4 has a higher boiling point, but dot 3 can handle the not flush of the brake fluid better then dot 4. Most ppl don't flush their brake fluid out ever 2 yrs so the dot 3 can handle that better.
 

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Like said above dot 3 & 4 are interchangable. 4 has a higher boiling point, but dot 3 can handle the not flush of the brake fluid better then dot 4. Most ppl don't flush their brake fluid out ever 2 yrs so the dot 3 can handle that better.
Don't forget the "new" DOT5.1 is interchangeable with DOT3 and DOT4

5.1 has the higher boiling point of all of them!
 

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Why isn't anyone questioning why he needs a fluid fill. Brake fluid is not a "usable" commodity. It only gets low when your brake pads wear or you have a leak. Two things that I would check immediately.
 
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Why isn't anyone questioning why he needs a fluid fill. Brake fluid is not a "usable" commodity. It only gets low when your brake pads wear or you have a leak. Two things that I would check immediately.
Don't forget it's the same tank for the clutch fluid too!
 

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Strichmädchen & Koks
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Why isn't anyone questioning why he needs a fluid fill. Brake fluid is not a "usable" commodity. It only gets low when your brake pads wear or you have a leak. Two things that I would check immediately.
While it shouldn't necessarily be consumed and need to be topped off, brake fluid does "go bad" over time, requiring a flush. The fluid will absorb moisture over time, which will reduce the boiling point of the fluid considerably.
 

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Why isn't anyone questioning why he needs a fluid fill. Brake fluid is not a "usable" commodity. It only gets low when your brake pads wear or you have a leak. Two things that I would check immediately.
The op has a '12 stick & like you mentioned could be the pads are half gone, IDK, & the light came on & he figured he'd check & add some brake fluid. No big deal, he was asking about what brake fluid to use.
 

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Torretto!
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Hmm...anyone run stainless brake lines, or know if they make a difference on mk3's? Add some german racing brake fluid too.
 

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Like the Blue & Yellow Ate Dot 4 fluid, easy to see when you've flushed it completely. (different colors of the same stuff so you can alternate)
 

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Strichmädchen & Koks
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Like the Blue & Yellow Ate Dot 4 fluid, easy to see when you've flushed it completely. (different colors of the same stuff so you can alternate)
Not available in the US any longer. Or at least, much more difficult to find. Some alphabet agency finally made them stop selling it as "brake fluid can't be blue", for some stupid reason.

Wish you could, just put the non dyed ATE fluid in last week, would've been a lot easier with the blue dye.
 

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What NFG bleepin' Stupidity, shared some in the past with a local Bud so we could keep it fresher on the shelf (use up whole cans that way).
 

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Like said above dot 3 & 4 are interchangable. 4 has a higher boiling point, but dot 3 can handle the not flush of the brake fluid better then dot 4. Most ppl don't flush their brake fluid out ever 2 yrs so the dot 3 can handle that better.
Never knew that Felix - thanks for the tip! Can someone tell me why one fluid type flushes easier than the other?
 

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Never knew that Felix - thanks for the tip! Can someone tell me why one fluid type flushes easier than the other?
It's not that flushing is easier from one to the other, it's that one doesn't absorb moisture as easy as the other, and the period between brake fluid flushes can be longer.
 
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It's not that flushing is easier from one to the other, it's that one doesn't absorb moisture as easy as the other, and the period between brake fluid flushes can be longer.
This^^^^^^^^^^
 
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