Synthetic motor oil

synthetic oils disapate heat better than mineral oils do, which is why they run cooler. as far as which is best, they are all petty good to begin with, right now i use mobil 1 in my cars, though i might run royal purple in my stang when it gets an engine built for it.
 
There are really only 3 true fully synthetic oils on the market available in the us.

Amsoil (My personal favorite)
Redline
Castrol as you purchase it from a BMW dealer. BMW imports the Castrol from Europe because it is true synthetic oil. The US version you buy at your auto parts store is not full synthetic (Most of the time...it is a hit or miss thing).

The definition of full synthetic was changed in the us to include the use of highly refined hydrocracked conventional base stock. All synthetic oils in the us (with the exception of the ones mentioned above) use some form of conventional base stock.

If you truly want to get the full advantages of synthetic oils like the extended change intervals (up to 30,000 miles) you should use one of the top three oils listed above.

Cheers,
Rufus
 
84convertablegt said:
the only reason switching to synthetic could cause a leak is because the oil is slicker and finds a way to slip through gasket imperfections that dino oil would kind of clot up on

Well, kinda..LOL.

Oil should not be clotting, if everything is going well!

Mostly full synths find leaks dinos don't because it is thinner oil for the same or better protection. That reduces friction, of course, but it also finds the smaller holes.
 
Reviewing the facts again indicates that you may be correct about mobile one super-syn. It does appear to be full synthetic. Royal purple is definitely not. I did run across this article when doing some research that explained the change in the definition of “synthetic” It is a good read.

http://www.1st-in-synthetics.com/newsletter_1000.htm

As far as leaking…It is all about the age of the motor and when it was last rebuilt with new gaskets. Dyno juice has inconsistent sizes for the base stock. Some are larger some are smaller. The larger ones will fill and plug any minute leaks you may have in old gaskets. The synthetic oils ate very consistent in their sizes, all very small. This is a huge advantage in film strength and friction reduction but it also means that it does not have larger particles that will plug any minute holes. In a really old engine this could result in some seeping of oil. I have never seen an engine “dripping” due to synthetic but I have seen them have an oil coating on valve covers and such.

Cheers,
Rufus