Synthetic Oil Viscosity
08-21-2007, 12:33 AM
#31
Addicted Specialist
Rennlist Member
Rennlist Member
LOL!!
Either what randy said about the tranny oil, or also that many had recommended against synths in the older cars because of the possibility of sprouting new oil leaks (where there were none) due to high-mileage engines that have had dino oil all their life. I've often "heard" this, but don't know if it's true. My SC has only about 25K miles on its rebuild, so switching to synth is no biggie for me ...IF it's true, that is.
Edward
Either what randy said about the tranny oil, or also that many had recommended against synths in the older cars because of the possibility of sprouting new oil leaks (where there were none) due to high-mileage engines that have had dino oil all their life. I've often "heard" this, but don't know if it's true. My SC has only about 25K miles on its rebuild, so switching to synth is no biggie for me ...IF it's true, that is.
Edward
Last edited by Edward; 08-21-2007 at 12:54 AM.
08-21-2007, 02:51 AM
#32
Racer
I use synthetic oils in all my vehicles, a Jeep Cherokee with 192K miles, a Dodge Dakota with 140K miles, and the 911 with 150K miles that used Castrol Dino oil up until 118K miles. The 911 oozes a tiny bit from the chain tensioner covers where it didn't before, and in fact all my vehicles ooze expensive synthetic oil. And I believe that the immense advantages in film strength and cold-weather flow are well worth it. I get really high mileages from my engines which retain excellent compression. How much does a rebuild cost vs. a couple quarts between changes? How obsessive-compulsive are you as far as antiseptic engine appearance? In my G50 I find that Redline synthetic with some standard GM friction reducer for the LSD makes it shift like silk. In an SC I would definitely use Swepco. Aside from oozing expensive synthetic oil, I don't believe there is any disadvantage to running any engine made on the proper viscosity synthetic, except for a real worn-out oil burner. If I had one, I'd drain my 911 oil and then put that in the oil burner for another 5000 miles. Heck, I use synthetic in my lawn mower. Delvac 5W-40! But I am no pro mechanic, professor or researcher so don't listen to me! 
08-21-2007, 04:58 PM
#33
Be sure not to confuse the G50 with the older Porsche trannys - it has different (Borg-Warner synchros) not the Porsche type synchros. The latter 'want' a fairly 'sticky' oil and Swepco is the stuff to use.
Synthetic motor oils did cause some leakage decades ago in old engines with poor seals. They all have a chemical additive now to expand the old seals.
Porsche says to use Mobil One in all their cars.
Synthetic motor oils did cause some leakage decades ago in old engines with poor seals. They all have a chemical additive now to expand the old seals.
Porsche says to use Mobil One in all their cars.
