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- DOT 4 brake fluid offers higher resistance to brake fade<\/li>\n\n\n\n
- These brake fluids have a higher boiling point<\/li>\n\n\n\n
- The chemical components offer better viscosity ratings<\/li>\n<\/ul>\n\n\n\n
On the other hand, you can\u2019t put DOT 3 brake fluid on DOT 4 systems as they are not compatible.<\/p>\n\n\n\n
![\"Can](\"https:\/\/taxiwiz.com\/wp-content\/uploads\/2023\/11\/Can-You-Use-DOT-4-Instead-of-DOT-3-1024x597.webp\")
<\/figure>\n\n\n\nWhy DOT 4 is Compatible with DOT 3?<\/h2>\n\n\n\n
To understand why DOT 4 brake fluid is compatible with DOT 3 but not the other way around, you will need to understand the functionality of the following factors:<\/p>\n\n\n\n
Fluid Base<\/h3>\n\n\n\n
The primary reason for DOT 3 brake fluids to be compatible with the DOT 4 brake fluid-based system is the fact that they share the same base element. <\/p>\n\n\n\n
Both brake fluids have the same base element. They are both made of glycol. <\/p>\n\n\n\n
This is why you can go ahead and put in DOT 4 brake fluid on the DOT 3 systems but can\u2019t put in DOT 5 brake fluid as it is made of silicon base.<\/p>\n\n\n\n
The Boiling Point<\/h3>\n\n\n\n
One of the key factors regarding the effectiveness of the braking system is the boiling point of the brake fluids.<\/p>\n\n\n\n
The boiling point refers to the temperature where the brake fluid starts to vaporize, when that happens the braking system will encounter a loss in performance.<\/p>\n\n\n\n
That\u2019s why the higher the boiling points the better the brake fluid is.<\/p>\n\n\n\n
When considering the boiling point, you should address the dry boiling point (the boiling point that is unexposed to moisture) and wet boiling (the boiling point that is exposed to moisture) point as well. <\/p>\n\n\n\n
Boiling Point of DOT 3 Brake Fluids<\/h4>\n\n\n
\n![\"DOT](\"https:\/\/taxiwiz.com\/wp-content\/uploads\/2023\/11\/DOT-3.webp\")
<\/figure><\/div>\n\n\nDOT 3 is the most popular and widely used brake fluid system on vehicles. They are especially popular among older car models, but new models also opt for them at times. <\/p>\n\n\n\n
The dry boiling point for DOT 3 fluids is 205 degrees Celsius or 401 Fahrenheit. On the other hand, the approximate wet boiling point is around 140 degrees Celsius or 284 Fahrenheit.<\/p>\n\n\n\n
These boiling points are perfectly suitable for driving on day-to-day roads and natural environments. <\/p>\n\n\n\n
Boiling Point of DOT 4 Brake Fluids<\/h4>\n\n\n
\n![\"DOT](\"https:\/\/taxiwiz.com\/wp-content\/uploads\/2023\/11\/DOT-4.webp\")
DOT 4<\/figcaption><\/figure><\/div>\n\n\n DOT 4 fluids offer a higher boiling point than DOT 3. <\/p>\n\n\n\n
Its general dry boiling point is around 230 degrees Celsius or 446 Fahrenheit and the wet boiling point is around 155 degrees Celsius or 311 Fahrenheit. <\/p>\n\n\n\n
As you can see, if you put the numbers together, there is around an 11% increase in the boiling point from DOT 3 to DOT 4. <\/p>\n\n\n\n
This means that the DOT 4 has 11% more resistance and protection than what DOT 3 can offer.<\/p>\n\n\n\n
But the increase in the boiling point isn\u2019t the main factor here. While there is an increase, it isn\u2019t significantly high.<\/p>\n\n\n\n
Therefore, braking systems that are designed to handle the boiling point of DOT 3 brake fluids can adapt to the boiling point of DOT 4 brake fluids as well. <\/p>\n\n\n\n
So, there won\u2019t be any complications, if you start to use DOT 4 brake fluid instead of the DOT 3 brake fluids. <\/p>\n\n\n\n
That being said, if you can, you should consult a professional or your vehicle manufacturer regarding this matter.<\/p>\n\n\n\n
Why DOT 3 isn\u2019t Compatible with DOT 4 Brake Systems?<\/h2>\n\n\n\n
While it is a fact that both DOT 3 & DOT 4 systems share the same base element that doesn\u2019t allow DOT 4 systems to work with DOT 3 brake fluid. <\/p>\n\n\n\n
This is due to the fact that the boiling point requirements of DOT 4 systems are higher than what DOT 3 fluid can handle.<\/p>\n\n\n\n
So, when DOT 3 brake fluid is put in a DOT 4 braking system-based vehicle, the brake fluid will evaporate at an alarming rate and will significantly affect the braking performance.<\/p>\n\n\n\n
Thus, it is regarded as incompatible to put DOT 3 brake fluid on DOT 4 systems.<\/p>\n\n\n\n
When DOT 4 Brake Fluid Isn\u2019t Compatible with DOT 3 Systems<\/h2>\n\n\n\n
There are times, when a DOT 3 system may reject DOT 4 brake fluids. The reasons behind this situation are as follows:<\/p>\n\n\n\n
The Parts of the Braking System Aren\u2019t Compatible with DOT 4 Fluid<\/h3>\n\n\n\n
In some car models, especially older car models, the parts of the braking system outright reject DOT 4 brake fluid. <\/p>\n\n\n\n
So, if the system completely rejects the brake fluid, then it won\u2019t be able to work and thus will be ineffective. <\/p>\n\n\n\n
Most modern car models don\u2019t have this issue that being said, if you are planning to put in DOT 4 brake fluid on DOT 3 system, then it is better to do your research first.<\/p>\n\n\n\n
You should consult the manufacturer’s guide regarding this matter. <\/p>\n\n\n\n
Otherwise, you can take your car to a mechanic and let him run a proper diagnosis to find out the compatibility of your vehicle.<\/p>\n\n\n\n
The Base Element of the DOT 4 Fluid isn\u2019t Glycol<\/h3>\n\n\n\n
While most of the time you will encounter DOT 4 fluids that have a glycol base. There are brake fluids for the DOT 4 brake system that is made of Borate Ester.<\/p>\n\n\n\n
Borate Ester and glycol are completely different components as one is an organic compound and the other is derived directly from alkylene glycols. <\/p>\n\n\n\n
But, DOT 3 brake systems are only designed to support brake fluids that have a glycol base, not a boron base or Borate ester. <\/p>\n\n\n\n
So, they won\u2019t function with that brake fluid, making the functioning of the fluid effectless.<\/p>\n\n\n\n
If these two situations arise then the DOT 4 brake fluid will not work with the DOT 3 system.<\/p>\n\n\n\n