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Stop Leak Oil Additives

Started by Quinton Bradford #25053, December 15, 2008, 03:02:29 PM

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Quinton Bradford #25053

Has anyone tried any of the "Stop Leak" type oil additives?  Has any one really had any luck with it really stopping any leaks?
Quinton Bradford
1963 Cadillac DeVille - "Gertie"

TJ Hopland

Where is the leak?  What vintage is the engine and has it been worked on recently?  If its a seal like on the crank there is a slight chance. Modern lip seals sometimes respond fairly well.  Rope type seals less. Often times the lip seals have cut into the metal so nothing but relocating the seal or a speedy sleeve will help.  If its gaskets they just need to be replaced.   If you have not already checked it would be worth checking all the bolts you can get to in case some have just worked themselves loose over time.  Its pretty common for valve covers to come loose, less common for oil pans.   On a old engine with old gaskets I use a 1/4" drive socket held like a T handle between my fingers so its just the little fingers have leverage and snug them down that way.  It has always helped more than magic products.  Frequent oil changes also seem to help because it gets rid of the bad stuff and adds new detergents and additives that likely include stop leak like products. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Otto Skorzeny

TJ summed it up pretty well.

How much is leaking and from where? I've always thought that topping up the oil whenever necessary is preferable to adding "rebuild in a can" type things. If I were planning major engine work sometime in the relatively near future, then I wouldn't worry about the additives so much.

I also run 20w-50 in my old vehicles . Even on the rebuilt engine in my '56, the rebuilder spec'd Pennzoil 20w-50.  It's less prone to find it's way through small gasket leaks, etc.
fward

Ask not what your country can do for you, but what you can do for YOURSELF

HUGE VENDOR LIST CLICK HERE

paulp

TransX is he only additive I have ever used that actually worked.  It absolutely stopped the leak in a Turbo 425 in an old GMC Motor Home I have.  Not the Trans X for cars but the stuff for Trucks.  Don"t know what the difference is.  Obviously I'm talking about a transmission here not an engine pan.   Paul P.  23300
Paul N. Price   CLC 23300

Mike Josephic CLC #3877

Stop leak additives are generally a waste of money.  The contain phenolic compounds that swell  rubber containing gaskets and may work for a time, but are not a permanent repair.

Much better to find the problem and either snug up the bolts or in worse cases, replace the gasket and you then have a permanent repair.  Sometimes that's not easy, but at least you fix
the problem.

Same deal on radiator stop leak products.  Read my article in the Self Starter from a few years back that details these products.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Quinton Bradford #25053

Thanks for the info!  Sadly enough, it is the rear seal.  A mechanic looked at it and said it would be around 3,000 to 5,000 $$ to fix the problem.  I'm hoping he just didn't want to do the job and gave me a high price.  I'm hoping for that price, I could have the total engine rebuilt!  I know prices vary from place to place, can anyone give me a ballpark figure on about how much I could be looking at to have this engine rebuilt?  It is a 390 for my '63 Deville.
Quinton Bradford
1963 Cadillac DeVille - "Gertie"

Otto Skorzeny

$3000- $5000 is a ballpark for a total rebuild.

At what rate are you losing oil? If it's merely an annoyance, at $2 a quart, you can add a lot of oil before you get anywhere near that price.

I believe the seal can be changed with the engine in the car. That quote seems high. Shop around and try to find somebody who is familiar with 50s and 60s cars.
fward

Ask not what your country can do for you, but what you can do for YOURSELF

HUGE VENDOR LIST CLICK HERE

35-709

I agree with Forrest!  You need to shop around for another mechanic! 
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Quinton Bradford #25053

I'll definately shop around.  It's not leaking a whole lot, I'm just getting tired of my wife complaining about the stains on the drive way!
Quinton Bradford
1963 Cadillac DeVille - "Gertie"

Otto Skorzeny

Just keep a bunch of flattened cardboard boxes in your trunk and slip them under the car when you park it. I small leak that doesn't affect performance is nothing to really worry about. I would just keep driving it until you have some really serious problem that requires major engine work. Fix it then. In the meantime, add oil when necessary.

I think that engine still uses a rope seal. Those leak a little bit anyway by design. You can buy new ones that are teflon coated and seal up better when the timecomes to replace it.
fward

Ask not what your country can do for you, but what you can do for YOURSELF

HUGE VENDOR LIST CLICK HERE

Ohio57-62Sedan

No such thing as a Mechanic in a bottle.  ::)  Save your money fro the real fix... A Seal Saver.. or A rebuild...  ;)

Quinton Bradford #25053

I've already got 'em in the trunk!  That and several quarts of oil!

Thanks guys!
Quinton Bradford
1963 Cadillac DeVille - "Gertie"