Hello. I have a Q: I had some work done with My brakes at the local autoshop near Me and the technik bleeded My brake system and replaced My old fluid with Dot 4. Read the manual and couple of threads here but still dont understand what kind of harm whould Dot 4 do? I think that I have a ABS. 1999 Blazer LT, 4,3L Vortec, 4-door, 4awd,

 

I am pretty certain it only takes dot 3, but I would not use dot 4 just to be sure. I don't really know what the difference is.

 

DOT 3 is recommended, however, DOT 4 can be used, but is not necessary. Both are polyglycol ether based fluids and are compatible. DOT 3 boiling point is 284F, and DOT 4 additives raise the boiling point to 311F. DOT 5 fluid is silicone based and should NOT be used under any circumstance.

 

Q What is the difference between DOT 3 and DOT 4 brake fluid?

The biggest difference between DOT 3 and DOT 4 brake fluid is their boiling point temperatures. DOT 4 has higher wet and dry boiling points than DOT 3. That i found out, but the manual says that: "use Delco Supreme 11 Brake Fluid (GM Part No. 12377967 or equivalent DOT-3 Brake Fluid). With the wrong kind of fluid in your brake system, your brakes may not work well, or they may not even work at all. This could cause a crash. Always use the proper brake fluid. Using the wrong fluid can badly damage brake system parts. For example, just a few drops of mineral-based oil, such as engine oil, in your brake system can damage brake system parts so badly that they’ll have to be replaced. Don’t let someone put in the wrong kind of fluid. "

So My question is will DOT4 damage My Blazer`s brake system parts when the difference between DOT 3 and DOT 4 brake fluid is their boiling point temperatures?

And if so then i`m going to war with My local autoshop. Its been since yesterday when they changed fluid and have driving it about under 50km (under 31 miles).

They sayd it is ok to use Dot4 and they allso used the word "definitely"
What to do next?

 

Thank You Captain . I`ll leave it in then. Drive couple of years and change it again.

Thanks for makeing My sleeping time calm

 

You'll be fine with DOT 4.