Does motor oil and DOT 3 brake fluid mix?

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JAG

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Why would I ask such a thing? Science, only. No practical reason. I have the answer and want to see what your guesses are and why you think your answer is correct.
 
Dot 3 is glycerin based, so is miscible with water and alcohol

It'll sink to the bottom of the oil pan.
 
You guys are correct about DOT 3 not mixing with motor oil. With agitation, I got it to somewhat mix, but after sitting still for a while, the two fluids separated.

Linctex somewhat touched on the why no miscibility. Why do they not mix?
 
Polarity and MW ?

On topic, we use a lot or re-refined oil for auxiliary fueling the boilers at work (250,000L for a cold start), 10-14Cst blend of used re-refined oil and diesel.

We had huge blockage issues a couple years ago. 5um filter as it goes onto the truck, and 25um filters blocked at the boiler.

Turned out to be glycol in the waste streams surviving the re-refiner, and then collecting (agglomerating soot particles, and forming quite strong stable particles).

They upper the upper temperature of the re-refiner, and problem went away.
 
Originally Posted By: Shannow
Polarity and MW ?


Turned out to be glycol in the waste streams surviving the re-refiner, and then collecting (agglomerating soot particles, and forming quite strong stable particles).



Is that necessarily from brake fluid (glycol ether) or could it be from coolant (ethylene or propylene glycol)?

Probably more coolant being disposed of than brake fluid, and its known to cause that kind of thing in an operating engine with, say, a popped head gasket.

I keep my used brake fluid for cleaning things. You can't buy water-miscible brush cleaner any more.
 
I have a few jars of used BF. I keep it around for air locks when I bleed. I don't like it on my skin and it tastes terrible. Is there any practical use for it? If not whats the best way to get rid of it?
 
Originally Posted By: Shannow
Polarity and MW ?

On topic, we use a lot or re-refined oil for auxiliary fueling the boilers at work (250,000L for a cold start), 10-14Cst blend of used re-refined oil and diesel.

We had huge blockage issues a couple years ago. 5um filter as it goes onto the truck, and 25um filters blocked at the boiler.

Turned out to be glycol in the waste streams surviving the re-refiner, and then collecting (agglomerating soot particles, and forming quite strong stable particles).

They upper the upper temperature of the re-refiner, and problem went away.

Yes, the polarities of DOT 3 and motor oil are too dissimilar to allow miscibility. The brake fluid is more polar. Perhaps at high enough temperature they would be miscible but not at room temp. and 125F.

I ended up adding the brake fluid because for weeks I had been experimenting with seeing if motor oil would dissolve a sliver of varnish that was composed solely of oxidized vegetable oil. The answer was “sort of, but mostly no”. I used Amsoil 10W-30, Maxima Formula K2 2-stroke oil (mostly esters), and Hy-per Lube polymer esters, separately. They did soften the varnish and give it flexibility that it lacked when dry. It also swelled. With gentle shaking, they did cause it to partially split apart. A very small piece or two did break off. Today I added brake fluid to the Amsoil that was already there. The varnish got even more flexible and swollen. Quite a few chunks broke off. The varnish became the consistency of mucous. DOT 3 is definitely more capable of dissolving vegetable oil varnish than the three other fluids I tested.

That’s an interesting story about the blockage from ethylene glycol.
 
Originally Posted By: andyd
I have a few jars of used BF. I keep it around for air locks when I bleed. I don't like it on my skin and it tastes terrible. Is there any practical use for it? If not whats the best way to get rid of it?

You tasted it!? :) I don’t know if it’s frowned upon but I plan on delivering used oil to a disposal place with a little bit of brake fluid in it. You could ask your collection place whether they accept brake fluid.
 
Originally Posted By: JAG
Why would I ask such a thing? Science, only. No practical reason. I have the answer and want to see what your guesses are and why you think your answer is correct.


You should never have brought this up. Someone on this forum will try putting it in their oil to "put the brakes" on oil deterioration to squeeze a few more miles out of an oil change.
 
When I went to sell the plastic rocker covers from my L67, they were heavily varnished.

Solvents just didn't touch it...a caustic based shop degreaser just ate through it/

When we had to clean the turbine oil tanks, caustic based clearners and hot water were the only way to get the crud out.

Save the glycol for wood preserver...sure that it would work like Ethylene Glycol...

https://www.bobistheoilguy.com/forums/ub...ool#Post4695285
 
Originally Posted By: andyd
I have a few jars of used BF. I keep it around for air locks when I bleed. I don't like it on my skin and it tastes terrible. Is there any practical use for it? If not whats the best way to get rid of it?


See my post immediately above. (I'm afraid I used ritten wurdz. I'm too lazy to make youtube videos just to communicate effectively with Americans)

Specifically, it makes a good carburettor cleaner, and MIGHT therefore be effective on intake deposits on trendy DI engines.

I've heard of it being used as a decoker/ring unsticker, but I might want to use fresh stuff for that unless the used stuff was really clean.

Its water miscibility means it can be effectively combined with water washing, as in boil-washing carburettors.
 
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Don's some people add brake fluid to the engine if it's leaking bad?
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Originally Posted By: slacktide_bitog
Don's some people add brake fluid to the engine if it's leaking bad?
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Some brave people may have done that. ATP 205 Re-seal seal conditioner is made of diethylene glycol monoethyl ether which is closely related to, or present in, some brake fluid ingredients.
 
Originally Posted By: JAG
Originally Posted By: slacktide_bitog
Don's some people add brake fluid to the engine if it's leaking bad?
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Some brave people may have done that. ATP 205 Re-seal seal conditioner is made of diethylene glycol monoethyl ether which is closely related to, or present in, some brake fluid ingredients.


LOL, like I said before with Kreen...

http://www.kanolabs.com/msds/kreen_liquid.pdf

simulating a headgasket leak to clean things up.
 
I didn’t realize Kreen has glycol ethers in it. I wonder how good of a gun bore cleaner brake fluid would be. Maybe that will be my next oddball experiment.
 
Originally Posted By: JAG
I didn’t realize Kreen has glycol ethers in it. I wonder how good of a gun bore cleaner brake fluid would be. Maybe that will be my next oddball experiment.


I can't comment about brake fluid but I can tell you Kroil makes for a very good bore cleaner, it works like a champ.
 
Originally Posted By: slacktide_bitog
Don's some people add brake fluid to the engine if it's leaking bad?
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I wouldn't call myself brave.....willing to experiment maybe... but I have done this on two leakers and its worked both times.

My friend was the chief mechanic for a small local sprint car race team, and he added brake fluid to oil all the time and swore by it. He was a little nutty though. Actually still is.

About ten years ago my 1995 Toyota 4Runner was putting a quarter-sized oil stain on my driveway daily due to a bad rear main seal. My emotional commitment to this truck had long expired, so I added 3-4 oz. of brake fluid and within a week or so the leak completely stopped. I ended up keeping it and drove that truck almost daily, including a lot of towing, and it never leaked again until I traded it in a year or so later. The mom and pop dealer I traded it in to, sold it to a friend of theirs. I stopped in to that dealer about a year later looking at another car and I asked about that 4Runner and they said the guy they sold it to was still driving it.

Did it again a while back on a friends beater Camry that was leaving three or four quarter sized drops daily. It didn't stop completely but now it leaves 1-2 dime size drops. That car still gets driven daily to this day.

That being said, I wouldn't recommend anyone else do this, at least not to a car they care about.....
 
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