964_UK

Hi Guys,

The oil for a 911 SC is 20W - 50 (am I right)

But is it Semi or Fully synthetic?

If you could let me know I would appreciate it.

Thanks

Craig

ked

Craig, there is much discussion of this timeless topic - try the search function for the full picture. the weight of oil one uses is a function of the manufacturer's recommendation (in your owner's manual), the ambient temp, how you operate your car & the condition of the engine. you can use any type of oil ("dino", semi or fully synth), as long as you heed the advice in your manual (esp oil & filter change intervals). good luck!

arbeitm

To make life a bit easier...Porsche factory fills all there cars with Mobile 1 (0W-40). I've used that in my 944 and will probably use it in my 911.

ked

I would never put a 0W- oil in an old air-cooled 911 motor. Those super thin oils are made for new water-cooled engines. ext low friction (CAFE), tiny oil passages for functions like variable cam timing control and minimal impact on cat convertor efficiency (EPA) & lifespan are the reason that the manufacurers are specing 0W oil. Oh, they also want to make life easy on their dealers (for once) by not requiring them to stock weights appropriate for older, higher mileage 911s. who cares if your engine won't last 200K miles? {all just my opinion, of course...}

300cd300sdl911

I struggled with the decision to change our '85 911 over from 20W-50 dino to Mobil 0W-40 for some time. Read all the posts both here and at other sites - be forwarned there is a substantial amount of data / opinions on this issue. Finally made the jump to full synthetic. Mainly due to my concern about running in colder weather and the viscosity change that would cause in dino oil.
So phychologically I'm past that now.....oil changed......no leaks. If you need more information check out: www.bobistheoilguy.com. An entire site dedicated to fun stuff like oil, grease, lubricants etc. Good luck.

bgiere

There are as many opinions as there are oils! In my experience the lowest wear rates ,using conventional,mineral oil in my 3.2 were achieved using a HDEO (heavy duty engine oil) such as Rotella T 15w40 or Chevron Delo 15w40. These oils (sometimes callled diesel oils) have the zinc and other additives that are necessary for our older air/oil cooled engines...I have found that a 40 weight oil reduced my oil temps and provided better wear numbers than any of the 20w50's I had previously used. If you want to use a synthetic, do not hesitate to use the M1 0w40...It is a very,very stout oil with a decent additive package. The "0" rating does not have any effect other than reducing cold engine start up wear...It's still a 40 wt. at operating temperature. Another synthetic that I use (in the Cup car) is Redline 10w40. It is hard to beat the results, although it's fairly expensive. The results I've had can all be verified by doing a Used Oil Analysis as I have done now for over 5 seasons of street driving and racing.

Edward

Hi Craig,

Indeed, there is LOTS on oil viscosity and brand selection in the archives. IMHO, the decision of proper viscosity is primary, more important that synth vs. semi vs. dino. And the decision of viscosity should be based on your climate and use (do you track it?). But I agree that since our engines are older and not designed with the the water-pumper's specs, I would never use anthing as thin as a 0W or 5W in our cars. The Porsche recommendation, I think, has more to do with their corporate concerns than with the long-term health of our engines. FWIW, I'd go with a 15w/50 synth such as Mobil1.

Edward

GothingNC

These oil threads keep popping up and get so darn confusing.
Too many choices, opinions, information etc.

About as bad as the threads about oil for the VW diesals on www.tdi.com

I'm going with Rottella until they change their formula.

John

964_UK

You're right, im more confused now than before I asked!

GothingNC

Don't ask about tires either

John

ked

John, I corresponded w/ Shell when I saw that RotellaT had been recently reformulated ("tuned" for the changes in diesel fuel & the cats that are being introduced on new diesels). I was provided straightforward guidance - that the old formula would remain available, at least for awhile (I bought a few extra 1 gal jugs), & that part of the new formulation is a modified additive pack to compensate for the changes, such that it would be a good oil for my use (I specified older, hi-perf, hi-reving gas engines w/ high mileage & in good working order).

So, I continue to use RotellaT in my step-kids BMW E30s (in the 318i w/ 175K mi I am trying their 5W-40 synth - we shall observe economy & consumption changes, in the 325e motor I am sticking w/ dino 15W-40, maybe shifting to synth next oil change - RotellaT synth may be the best deal on a high quality oil on the market - don't let this out or they will start marketing it to consumers & the price will go up accordingly), in my Benz (150K mi 300TE) & in my 356SC. As per Edward, Mobil1 15W-50 goes in the '87 911 (115K mi).

GothingNC

Ked,

Thank you !

John

964_UK

So what you using in your car John?

GothingNC

PO used Castrol 20W 50 and changed the oil every thousand miles and after every DE event.

Motor now has about 18,000 miles after top end rebuild.

I've had the car since Feb 06 and have put about 2,500 miles on it.

John

964_UK

ok cool.

NIce info, thanks!