Are you suggesting that before I tried mobil 1 that I already had leaks, except they were the kind of leaks that don't leak?

If you have no leak, and put in syn, then you have leaks...

Semantics... I give up.

What are you up to this weekend? I'll be on my way north again to Frazier Park, lemme know if you need a hand i can stop by on saturday morn.

 

I believe that the benefits of a synthetic oil are worth any leaks that may result from its use....so I use it in all my vehicles, even the old ones.
Valvoline makes a nice full synthetic, if you are brand-loyal.

Larry
code5coupe

 

It's not so much semantics, as it is the truth. The oil is "thinner", due to the lack of those waxes. The synthetics will simply find leaks that the other oils blocked off. The synthetics eventually wash away some of the laquer and waxes, finding said leaks.

 

Ah, so you're talking about the "leaks that don't leak" that my motor used to have before I tried synthetic...

I don't call those leaks, but you do, and that's why it said it was semantics. What was this post about anyways?

 

Let me clarify the comment on synthetics being lighter weight and that causing leaks..... It a'int so!

SAE, the Society of Automotive Engineers classifies the weight ( viscosity or thickness) of motor oils.
a 5W motor oil has a CCS (cold cranking simulator) viscosity of 6,600 centipoise (max) at -30 degrees celcius. A 10W motor oil has a viscosity of 7,000 centipoise (max) at -25 degrees celcius.
Similarly at the high temperature end, the 5W must have a minimum viscosity of 3.8 centistokes at 100 degress celcius and the 10W has a minimum of 4.1 at the same temperature.
Whether it is synthetic or conventional ,two oils that exhibit the same viscosity will be classified the same by the SAE. If they exhibit different viscosities they will be classified differently.
That means that two 5W30 motor oils will within the accuracy of the classificiation have exactly the same viscosity whether they are conventional or synthetic does not matter.


Any leaks that occur with using synthetics are solely attributed to their superior detergency. Synthetics keep you engine cleaner and keep the combustion by products in suspension longer. That means they can remove deposits like sludge or varnish that have migrated and plugged leaks in gaskets. Once the sludge is removed the hidden gasket leak is revealed.

 

Yup, and a 5w30 oil will have 5 weight viscosity at 0(?) C, and 30 weight viscosity at 100(?) Celcius.

 

Thanks for all oil advice. I got an education, and enough info to make a decision. I did get some info, and may get the answer I need.
I called the Chevy dealer that serviced this 89R, and was told to call back today, they may have what I need.
Boatman