Author Topic: Stop Leak Oil Additives  (Read 1978 times)

Stop Leak Oil Additives
« on: December 15, 2008, 02:02:29 PM »
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"

Online TJ Hopland

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Re: Stop Leak Oil Additives
« Reply #1 on: December 15, 2008, 02:19:15 PM »
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. 
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Offline Otto Skorzeny

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  • 1956 Coupe de Ville aka Bismarck
Re: Stop Leak Oil Additives
« Reply #2 on: December 15, 2008, 03:44:49 PM »
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

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Offline paulp

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Re: Stop Leak Oil Additives
« Reply #3 on: December 15, 2008, 04:13:45 PM »
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

Offline Mike Josephic CLC #3877

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Re: Stop Leak Oil Additives
« Reply #4 on: December 15, 2008, 08:52:33 PM »
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
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Re: Stop Leak Oil Additives
« Reply #5 on: December 16, 2008, 07:06:14 AM »
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"

Offline Otto Skorzeny

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  • 1956 Coupe de Ville aka Bismarck
Re: Stop Leak Oil Additives
« Reply #6 on: December 16, 2008, 07:37:06 AM »
$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

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Offline 35-709

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Re: Stop Leak Oil Additives
« Reply #7 on: December 16, 2008, 08:27:16 AM »
I agree with Forrest!  You need to shop around for another mechanic! 
1935 Cadillac Sedan
1973 Cadillac Caribou
1950 Jaguar Mark V Saloon

Re: Stop Leak Oil Additives
« Reply #8 on: December 16, 2008, 09:27:21 AM »
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"

Offline Otto Skorzeny

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  • 1956 Coupe de Ville aka Bismarck
Re: Stop Leak Oil Additives
« Reply #9 on: December 16, 2008, 09:55:54 AM »
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

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Ohio57-62Sedan

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Re: Stop Leak Oil Additives
« Reply #10 on: December 16, 2008, 10:03:08 AM »
No such thing as a Mechanic in a bottle.  ::)  Save your money fro the real fix... A Seal Saver.. or A rebuild...  ;)

Re: Stop Leak Oil Additives
« Reply #11 on: December 16, 2008, 10:05:31 AM »
I've already got 'em in the trunk!  That and several quarts of oil!

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

 



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