That's the soluble oil that is the carrier for the Bar's Leak
pellets.  And you should not have added it to the overflow tank.  It
needs to go in the pressurized header tank and might I suggest
Alumiseal instead? You will need remove and flush the overflow tank.

Jim

On Jan 21, 2010, at 5:11 PM, Greg S wrote:

> I should note that I added the bar's leak to the non presurized
> coolant bottle
> where I normally add antifreeze.
>
> On Thu, Jan 21, 2010 at 8:05 PM, Greg S <sorkilmo@gmail.com> wrote:
>
>> Hi nice people
>>
>> I had a really small antifreeze drip coming from my engine and
>> decided to
>> add some bar's leak to see if this would seal it up. The leak seems
>> to have
>> stopped but when I checked the filling tank, about 3 days after
>> adding
>> bar's, I find that the antifreeze has about 1 inch of milky white
>> liquid on
>> top of it. The engine runs fine and the temperature gauge reads
>> normal. I am
>> wondering if anyone has used bar's leak before and had the same thing
>> happen. Could this also be a sign of a head gasket leak? I would
>> welcome any
>> advice on this matter.
>>
>> Thanks,
>> Greg S
>> 87' Wolfsburg Hardtop
>> Ottawa Ontario
>>