The only thing it's able to clean off is carbon deposits. If you had carbon deposits on seals or your rings and they are removed, it would make absolutely zero difference as far as oil seal goes.

Piston rings exert about 5-10psi of spring tension seal against the cylinder wall by being forced outward through the thousands of PSI the compression stroke creates ontop of the piston.

As far as cleaning seals, it would help lubricate and swell the rings as well, which I mentioned in my post above.

 

I have a nice, thick, black layer of carbon on everything Why would Mobil1 swell the rings? I don't quite understand.

How could one clean the carbon off the pistons? Would seafoam or similiar do it? I always assumed the detergents in gasoline would cook carbon off the pistons.

 

Well, the question(s) in my mind is that if I switch oils... how or why is it that one oil would swell the rings more than another oil and/or if the rings are already swollen due to an oil, how would they swell even more with another one???

 

Synthetics tend be a thicker in viscosity versus a traditonal mineral based oil with the same rating. Because of this, it exerts more pressure against seals and rings and helps seal them shut.

You'll find a lot of times people who begin to burn a lot of oil will switch to a thicker oil grade to slow down burning for this same reason.

Higher octane gasoline tends to gain more detergents to PREVENT carbon deposits but is not going to do a very good job at cleaning thousands of miles of exisiting buildup.

For cleaning up engine parts such as valvetrain components, degreaser and a rag usually works fine. Piston tops usually are stubborn, I've cleaned pistons in the past by using degreasers and a wire brush. You need to be careful that you only use the brush to break up the carbon deposits and not to scratch the fuck out of the top of the piston, the metal is pretty soft.

There's other methods. I mean if you wanted the entire block cleaned, you send it through a jet cleaner or a hot tank.

Synthetics offer detergents that help break down deposits but won't remove them all.

 

But I know that I have heard in the past that if you've run regular oils for most of the time and then you switch to a syn, that you can start burning oil (your car start smoking, etc.)....

 

This is only true if you go from mineral based, to synthetic, then back to mineral based.

Because everything has swollen up and expanded with the synthetic, putting in a mineral (thinner) oil will be able to seep past seals that the thicker synthetic wouldn't be able to.

 

yes is very true what he said.

 

What about just the Castrol High Mileage stuff?