I have a 1985 911, on my last oil change I switched to synthetic, was that a wise thing to do, if not what oil should I use?
I don't remember the balance of opinions on this when I had an '88 Carrera, but I switched to Mobil 1 synthetic. As I recall, some said that there was a possibility that a non-leaking 911 might develop an oil leak as a result, maybe due to the fact that some might be switching to a somewhat thinner oil. My 911 didn't develop an oil leak, and the synthetic seemed to work fine; at least as far as I know.
Otherwise, going by the list of approved oils in your owners manual should be a safe bet.
I believe there have been several letters to Excellence magazine on this subject and if I recall correctly it was recommended not to use the synthetics when changing oil in the older 911s. I just don't remember why. I would search renntech.org for the answer.
I switched my '65 356SC to Mobil 1 V-Twin motorcycle oil years ago - no regrets.
Remember the older cars need zinc.
Locally you can get Valvoline VR1 racing oil- (non syn) That will have the ZDDP you need. Otherwise, order Brad Penn.
Thanks for all the advice.
I think it is always a good idea to switch or go with a full synthetic oil. I use Mobile 1. The synthetic oil just has better lube properties and less breakdown. The big thing is to make sure you get the right weight as per the manual for your vehicle.
I've got an '81SC, '88 Carrera, (it replaced a '87 Carrera), '06 Cayman S, and an '09 Carrera S. All have Mobil 1 in the tank or crankcase, as the case may be. The '81 has been using Mobil 1 since I got it 150000 miles ago in '85, and none of them leak oil anywhere. The Mobil 1 is especially effective for the air cooled motors (15W-50) as engine and oil temps can be in the 230 F+ range. There's a lot of piece of mind having a good synthetic inside at these elevated oil temperatures.
