I’ve had my 993 for over 20 years, and always used mobile 1 for my annual oil change. With 100k miles, I now have some leaks. Is there a different brand oil that slows the leaking?

 

What is leaking? Chances are its time to change some seals. Clearly its not the oil causing the issue, as you've been using the same oil for 20 years. Using a different oil that would theoretically stop the leaking would be addressing the symptom and not the disease.

 

Air cooled cars leak oil. It’s the nature of the beast.

 

+1 on this.

You may find a thicker oil like 20w-50 leaks slightly less than 15w-50, I doubt it. Leaks are just a fundamental of time and seals shrinking. The leak won't get better on it's own. However, you can have a dry engine once the offending seals are dealt with.

 

This is simply not true.

Sure a lot of aircooled cars seem to develop leaks over time, but if you replace seals/gaskets they will be leak free. Mine's been leak free for 6 or 7 years now.

 

25 year old seals are probably going to allow some seepage. you can definitely reseal and address it but a small amount of leakage isn't hurting anything other than your garage floor.

 

This one of the reasons oil companies started the High Mileage oils due to increased seal conditioners,etc. The problem is our cars are susceptible for seeping and leaking well before those advertised 75K levels. Furthermore, not aware that any of HM oils have adequate additives like Zinc and Phosphorus to satisfy the flat tappet requirements. Last, you could try Liqui Moly Motor Oil Saver before opting for resealing the engine. Good luck with your quest and keep us posted.

 

Different oil will make no difference... your seals are shot and need replacement.

 

Seals don’t really “shrink”, it’s the onset of stress relaxation, compression-set and loss of resilience due to heat cycling. But the bottom line is they loose sufficient contact pressure with mating surfaces and allow leakage.

 

Where are the leaks coming from? If the case/heat exchangers/etc are dirty it will be hard to tell. First thing you should do is clean the case/ heat exchangers ( basically anywhere you can get some brake cleaner and a rag.) Then go for a 20 minute drive. Once back home look to see where the leak is coming from. It is much easier on a clean engine.

Typical spots that leak are:

1. Lower valve covers.
2. Cam shaft covers.
3. Oil breather cover gasket (next to Pressure sending unit in mid right rear of engine compartment).
4. Oil filler over flow.
5. Case half seams.
6. Oil drain plug.
7. Oil tank drain plug.

 

Hi Silver Porsche,
100K miles before the lower valve covers begin to leak, I'm impressed!
About halfway down this page are my thoughts on oil leaks.
https://993servicerepair.blogspot.co...nsumption.html
Andy