[JFP in PA]

Originally Posted by jakeru

Hmmm.... I'm just trying to figure out what's in this stuff.

[from https://www.gobdp.com/wp-content/uploads/2014/08/BlueDevil-Transmission-Sealer-SDS3.pdf]

" > 90% Proprietary Ingredient"
"SARA Section 313 - Emission reporting: Glycol Ethers Category".

..and also from https://gobdp.com/wp-content/uploads/2014/01/00236_TSL_MSDS.pdf

"CAS # EINECS No Name % Concentration Warning, Risk phrases
111-90-0 203-919-7 Diethylene glycol 20%-95% R36
+ monoethyl ether
NA NA Proprietary Mixture 5%- 30% R2-/21/22
Trade Secret"

Not your usual "water glass" type stop leak product. Maybe the solvent properties are intended to clean dissolvable build-up, (assuming some sort of dissolvable build-up was preventing sealing and causing leakage)?

Those are seal softening compounds designed to soften up seals that have hardened over time.