MolaKule
Staff member
Bob,
"Now with the dirt and grime gone acting like a seal, it starts to
cause leaks after being cleaned more so with synth's than with the conventions with less cleaning abilities. "
I saw this exact situation with the Gulf-II, Mobil and early Amsoil's back in the early to mid-seventies . Upon introduction of the synth (after using dino's), the sludge "seal" was removed (I.E., the synth's di-esters removed the hardened sludge at the seal interface). This was ONLY the case when Mobil's early 5W20 and Amsoil's 10WXX products were primarily di-esters. What I saw in many cases, was the ester "overswelling" the seal which caused wearing of the inner bore of the seal causing leaks. Later, additives were introduced which negated the di-ester's overswelling.
Then their formaulations went to PAO's and various flavors of polyol esters. The PAO's slightly hardened the seals whereas the ester slightly swelled the seals, and subsequently, they summarily cancelled each other's seal activity to a somewhat neutral state, with only slight seal swell - which is what is needed!
BTW, and we should clarify, we are discussing SEALS which mate with a rotating component such as a journal. Oil pan GASKETS and valve cover GASKETS are made of different materials.
"Now with the dirt and grime gone acting like a seal, it starts to
cause leaks after being cleaned more so with synth's than with the conventions with less cleaning abilities. "
I saw this exact situation with the Gulf-II, Mobil and early Amsoil's back in the early to mid-seventies . Upon introduction of the synth (after using dino's), the sludge "seal" was removed (I.E., the synth's di-esters removed the hardened sludge at the seal interface). This was ONLY the case when Mobil's early 5W20 and Amsoil's 10WXX products were primarily di-esters. What I saw in many cases, was the ester "overswelling" the seal which caused wearing of the inner bore of the seal causing leaks. Later, additives were introduced which negated the di-ester's overswelling.
Then their formaulations went to PAO's and various flavors of polyol esters. The PAO's slightly hardened the seals whereas the ester slightly swelled the seals, and subsequently, they summarily cancelled each other's seal activity to a somewhat neutral state, with only slight seal swell - which is what is needed!
BTW, and we should clarify, we are discussing SEALS which mate with a rotating component such as a journal. Oil pan GASKETS and valve cover GASKETS are made of different materials.