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View Full Version : Engine seal leak - Brake fluid cure?


brucepick
08-21-2005, 07:25 AM
[Thanks to all for your posts on this.
No brake fluid for my motor oil!
I may have a look at the breather box after all.
Can't hurt.]

I've seen a suggestion re. a brake fluid cure for leaky engine seals. That is, add 6 oz DOT-4 brake fluid to the engine oil, change out after 300 miles - supposedly rejuvenates the seals. Improvement to be seen after about 100 miles.

Has anyone had success or failure with this treatment?

This could be useful for me, as my brick ('89 245 NA) has been leaving 4-6 inch puddles on the pavement when parked. It's the rear main seal. Flame trap system inc. brether box is verified clear.

I'd like to change to synthetic oil for the winter - With regular oil, I need a change every 3K miles or 3-4 weeks (long commute). It's no fun in the New England winter. Synthetic should get me through the season without oil changes. But I don't really want to feed a leaky seal at the price of synthetic oil.

TIA

740Weapon
08-21-2005, 07:47 AM
I've seen a suggestion re. a brake fluid cure for leaky engine seals. That is, add 6 oz DOT-4 brake fluid to the engine oil, change out after 300 miles - supposedly rejuvenates the seals. Improvement to be seen after about 100 miles.

Has anyone had success or failure with this treatment?

This could be useful for me, as my brick ('89 245 NA) has been leaving 4-6 inch puddles on the pavement when parked. It's the rear main seal. Flame trap system inc. brether box is verified clear.

I'd like to change to synthetic oil for the winter - With regular oil, I need a change every 3K miles or 3-4 weeks (long commute). It's no fun in the New England winter. Synthetic should get me through the season without oil changes. But I don't really want to feed a leaky seal at the price of synthetic oil.

TIA

in popular mechanics some guy wrote in that he tried brake fluid and he ruined his engine bearings and needed a new engine.

brucepick
08-21-2005, 03:55 PM
Ouch.

89740ti
08-21-2005, 07:25 PM
in popular mechanics some guy wrote in that he tried brake fluid and he ruined his engine bearings and needed a new engine.
Which, in effect, cured the oil leaks..... :-P

brucepick
08-25-2005, 01:00 PM
Someone suggested I use Auto-RX.
auto-rx.com

Any comments?

740TurboPerformance
08-25-2005, 01:46 PM
The best way to reduce or potentially cure leaks is to completely and thoroughly clean the entire PCV system to reduce blowby and excess crankcase pressure then run some slightly thicker motor oil, if it keeps leaking bad the seals need to be replaced although it should reduce if not cure the leakage.

brucepick
08-25-2005, 01:52 PM
Winter coming.
Kinda should stay with 10-30.
Would prefer to go to synthetic, which is what started me on this thread.
I don't want to feed higher priced synthetic oil into a leaky motor.

Hagar17
08-25-2005, 01:56 PM
I heard thicker oil would increase leaking because of the pressure of thicker oil produced by the blow by (such as past the rings )

danny_b
08-25-2005, 03:41 PM
Brake fluid in the engine block, I don't think so, it was designed for brake calipers and cylinders, the material used for seals is oil resistant and now days most seals in the engine are also oil resistant. In the past brake fluid would swell up rubber products and this is where this "Brain Storm" came from. There are some products made you can purchase at your local parts store that should cure your problem short term. Brake fluid has no lubercation properties and if introduced to your crank case will cause damage to every metal to metal part.

dl242gt
08-25-2005, 03:53 PM
If you plan on keeping the car going for a few more years it's worth it to fix the bad main seal. You can also save a good chunk of money by moving your oil changes to 5k miles. Modern oils are so good that you are wasting money with 3k mile oil changes. Especially someone with a long commute because you are running the engine long enough to always vaporize the water and other crap that accumulates in the crankcase.

Best regards,

740TurboPerformance
08-25-2005, 03:57 PM
fully synthetic is fine.

Before anything I would make sure the entire PCV system is spotless before causing more serious leakage or completely blowing out seals or multiple seals.

The thing about synthetic is that it has greater fluidability and pour properties. Pour a bottle of 10w40 fully synthetic next to 10w40 and you'll see the synthetic pours like water compared to the conventional regardless of it's rated viscosity/weight.

I run 15w40 fully synthetic with no issues but that's california climate. 10W40 fully synthetic should be close to the same as 10w30 conventional. It also flows better in cold temps, is more slippery and is less prone to thermal breakdown at higher temps. Thicker oil on top of a clean PCV system will help reduce and possibly even stop leaks and consumption unless it's too late and that seal is completely blown. 15w40 fully synthetic has reduced my oil consumption in my '88 745T. Running slightly thicker oil has also helped slow down a rear main leak with my '87 740T after cleaning the PCV system.

leowes
08-25-2005, 07:46 PM
brake fluid swells seals and gaskets. nice temp fix if unloading car, but leaks will reappear with a vengance. you dont need much 3-5 oz will do. also works wonders in auto trannys that exhibit delayed gear engagement and shifting when cold.

Zee
08-26-2005, 08:46 AM
Someone suggested I use Auto-RX.
auto-rx.com

Any comments?

I'm using is in four of my vehicles. And doing oil analysis testing. Nothing in my reading about Auto-RX sugggests it improves or fixes seals.

740Weapon
08-26-2005, 10:04 AM
you know they do sell oil aditives to slow leaks. most are just really thick oil... but better than brake fluid.

brucepick
08-26-2005, 02:58 PM
I'm using is in four of my vehicles. And doing oil analysis testing.

How many miles driven for your cars while using Auto-RX?
Anything good or bad to report on it??

TIA

brucepick
08-26-2005, 02:59 PM
you know they do sell oil aditives to slow leaks. most are just really thick oil... but better than brake fluid.

The old "Motor Honey". I wouldn't touch that stuff as far as bricks are concerned.

Hank Scorpio
08-26-2005, 03:01 PM
hahah brake fluid :rofl:

mAydAy
08-26-2005, 03:06 PM
Brake fluid will definitely do it, the problem though is it blows every other seal out of the engine that isn't leaking, and then they just disentigrate after a while. Just do the rear main, its not a hard job. Seriously though, don't do the brake fluid, I've seen it done before, and once saw it done on a Ford C4 trans also. Its not pretty.

-Andy