Please... Not another oil thread.

[Bill Douglas]

To keep it brief, I promise.

My SC engine is sweet and I want to keep it that way. I warm it up well, never ever gets overheated, has a Carrera oil cooler, I change the oil often with a top quality zinc rich mineral oil.

In my situation would a good synthetic oil be better for the engine's longevity? Or are synthetic oils only better in extreme situations (heat?) where the mineral oil is breaking down.

[doug_porsche]

Every thing in my post may be wrong.

At one time, on a different forum, we had a career tribologists who frequently posted. He not only actually knew what all the numbers in the BlackStone report meant, via his work, he had access (and knowledge) to the machines the produce the BlackStone numbers.

I asked him your exact question, in all fairness it was 10+ years ago, and his answer was...

For an air cooled Porsche, it was worth it to use synthetic.

Todays dino oil is amazing stuff. Even the average quality oil is better than the best oil you could get not long ago.

Todays synthetic is frequently not 100% synthetic.

The advantage, as per the tribologists, was that synthetic is better at extremes (like you said).
It flows better cold, it offers better protection hot.

Under normal usage (for liquid cooled cars, driven in normal usage), Dino-oil is fine.
I have read that under normal usage, if you change your oil every 5K miles, you will never have an oil related failure.

If you use your car outside these parameters, the added protection of a synthetic starts to make sense.

Unfortunately for you, air cooled cars, even when driven in a responsible manner (i wouldn't know how to do this though), asks more from the oil. The oil temps vary more than in a liquid cooled car.

Although you would probably have no issue with dino-oil that is changed regularly, I would spend the extra coin to go with a good synthetic.

Every thing in my post may be wrong.

[Bill Douglas]

Thanks Doug. I did like what I heard about that synthetic Liqui Moly in a thread a week or two ago.

[p911dad]

Years ago, the opinions I heard said that when initially switching from dino to synthetic the synthetic oil could slip or weep past the old seals in the engine and turn your car into a leaker. I don't know if this is actually true but seemed to be plausible I changed our 84' Carrera from dino to Mobil 1 20W50 and it indeed did start to show oil where it never had before. I continued with the Mobil 1 because I figured once the seal is breached it will never seal tight again. Or, on the other hand, old seals will leak eventually anyway, so who knows.. I personally believe that the advantages of the synthetic over the dino, considering how expensive these engines are to rebuild, make it good to move to the synthetic. Just sayin'

[1990C4S]

I am personally heading to Mobil1 full synthetic for everything I drive...I still have some Brad Penn 20W50 for my air cooled car, but I will be switching over to Mobil1 eventually.

[unclebilly]

I believe in Brad Penn and this is what my air cooleds get. Everything else gets Penzoil Platinum.

I asked (likely that same) tribologist over breakfast about the Penzoil Platinum and he felt that give the consistent chain length, it would be a superior synthetic oil.

[GH85Carrera]

Bottom line, like many things opinions are all over the place. Modern synthetics, and dino oil are bot quality stuff. Brad Penn for me. I never see oil temps above 220. It is a very rare thing but I do see low outside temps. I have started it in 16 degree weather, and the oil pressure was instantly at 5 bar.

[MBAtarga]

I've heard (seen on this forum) going full synthetic oil can cause leaks - if the engine has been fed dino oil previously. Only after rebuilds (new seals) should you consider synthetic. Maybe this is an old-wives tale?

I've recently swapped from a different brand and am using Valvoline VR-1.

[Por_sha911]

This was a major debate back when the formula requirements set by the govt reduced ZDDP in motor oil circa 2003-05.

Many folks with air cooled motors said they had leaking only after the switch to synthetic. The consensus was to a good quality oil with the proper amount of ZDDP. Also, avoid additives which can throw off the balance of the package in the oil.

I used Brad Penn 20W50 for years but can get Schaeffer 7000 plus 20W50 locally which is 10% synthetic. It is formulated for flat tappet cam motors. Either one is great IMO.

More more thought: there are different types of synthetic. Some are purer than others. Do the research. There is a TON of info in the tech forum.

[RWebb]

There is a Mobil One with plenty of ZDDP - search up Bill V.'s posts on it

[Baz]

FWIW....they make motor oil that is part dino and part synth.