<VV> Re: RTV vs oil and gasoline

[Tony Underwood]

At 04:29 hours 07/21/2004 +0000, djtcz@comcast.net wrote:
>> I discovered decades ago that RTV isn't worth a tinkers damn for sealing 
>> against oil or gasoline or most any other petroleum based liquid. Water 
>> and air etc it's fine, nothing better. But it's worse than nothing for 
>> gas or oil. 
>> 
>The Blue and black RTV silicones sold as gasket sealer hold up to oil
well, but like you say, fail miserably around gasoline.  The gasket product
instructions mention what's acceptable.  I just looked at a tube of GE
Silicone II tub sealer and it says not for use below the waterline. No
mention of use as gasket sealer.
>_______________________________________________  


I might trust RTV as a supplemental gasket sealer as in smearing a thin
coat onto a paper or composite gasket etc but I'd not trust it much farther
than that.   I once removed a PG pan which had been supplementally "sealed"
with RTV on the new cork gasket and upon unbolting the pan it simply fell
off, RTV still stuck to the gasket with a passion but not a hint of seal to
the aluminum PG case or the pan itself... and yes it had been leaking
bigtime again in spite of the new gasket and RTV all over.   It likely
wouldn't have leaked with nothing but a dry cork gasket alone if the P.O.
had simply straightened the pan rail a bit.    The RTV was evidently
expected to "fill the voids" between the pan and the gasket and the ATF
just unseated the RTV and dribbled past it onto the ground.    

Then again, perhaps the newer RTV compounds today might be better around
oil...?      


tony..