Oil change

Im fixing to do my first oil change on my 1973 911T, Im not sure of the mileage or anything else on the car. Any ideas on what would be the best thing to use? Synthetic, full or partial blend 10/40 10/50 . Anything will help...

I use Valvoline synthetic blend and I am pleased with it 10/40 in winter 20/50summer
Be sure and use a Porsche or Mahle brand filter the check valve is set to proper specs

On a car that old, with an unknown history, I would personally stick with a non-synthetic oil. If you try a synthetic, I think there is a good chance you will encounter oil leaks, which may or may not stop if you switch back to dino oil.

Before my 914 2.0 was rebuilt, I tried Mobil 1 15-50 in it, and believe me, it leaked like a sieve! (where previously it only leaked like a leaky bucket).

Synthetics are nice, but not essential. Your car has been running for 30 years on dino oil, including old, non-detergent straightweights which were far inferior to today's modern dino oil. I personally would just stick with a major label dino oil for your car, change it regularly, and you will be fine.

I recently replaced all of the seals and gaskets on my '78 SC, but even then am going to stick with dino oil in that car.

Brian

Got to agree with Brian. Cars built well into the early nineties were designed in the days before Mobil 1 and those trick lighter grades can end up seeping all over the place. Do your maintenance well (even change the oil at twice the specified intervals as many of us do) and you'll be fine.

Brian is correct. You run the risk of developing leaks in places that Porsches might not normally leak from, since we all know that they do. The synthetic oil will help the old gaskets deteriorate, hence the leaks.

I usually run 20/50 all year round, but I don't really drive the Porsche in the winter. Some of the guys switch to 10/40 for the colder months.

Yep, the last thing I need is more oil leaking out, seems like theres already a funnel under there anyways. I hope to get all of that fixed up soon. Thanks for the input.

You know, my 86 Targa doesn't leak at all with 20/50 in it. There's a little slathered around the return tubes, but literally not enough to drip at all. No spots on my driveway.

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Mark Szabo
1986 911 Targa 3.2

If you have been running Synthetic oil can you go back to regular oil. I have a 90 C2 3.6 should I only run Synthetic?
Thanks

[This message has been edited by Taylor (edited 12-28-1999).]

Since you are just getting into the maintenance on this older car I would strongly recommend against a synthetic at this time, way too expensive to see leaking out on the pavement! Valvoline Racing 15W-50 has served me well for many years, year round, and believe me, it is almost as hot in West Texas as Death Valley in August.

With a car that old it would probably be a good idea to get a couple of new pressure regulating and bypass springs from a dealer (I think it is the same spring in both places) and plan on changing them out at the same time as the oil change. Sometimes, with age those springs can weaken and reduce your oil pressure ... a cheap item to replace, and take care of one potential worry.

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Warren Hall
1973 911S Targa