5w-40 synthetic in a 911sc

[red83911]

Its coming up to oil change time, using a semi-synthetic 10-40 without any issues. Milage is 60,00 no major leaks. Have the chance of a good deal on Shell Helix ultra (fully synth) 5w-40. Car is spring and summer use in the uk.
Any one using/used shell 5w-40?. is there any benefit or should I stick with the semi synthetic 10-40.

Thanks Richard

[ja78911sc]

I have read of cars which have zero oil leaks when using a standard oil. When they switch to a full synthetic the cars develop a leak. Especially on older seals and gaskets.

[84porsche]

I am trying a synthetic blend (I believe 5W30) in my P-car right now and haven't seen much more with respect to oil leaks.

[Wil Ferch]

leak tendency depends on "which" kind of synthetic....

Do a search, there is a lot of info in here...seek out "oil bible"...

Wil

[anthony]

5w sounds low to me unless it was just for winter driving.

[Wil Ferch]

I use 5W-40 Shell Rotella -T Synthetic ( USA product only... I believe).... no problems... no leaks...but this is a highly refined Group III synthetic oil that is allowed ( by US law) to be called "100% synthetic"...

May not be marketed as such elsewhere..... but it really does perform as well as the PAO "true" 100% synthetic oils ( earlier Mobil 1) , but Mobil 1 leaked for me.

-Wil

[bigchillcar]

5w defintely sounds like winter only..thin stuff and synthetic to boot..wow. your motor must be a nice tight one, wil.
ryan

[gduke]

Here in the states any oil the is API approved is a good oil. Somewhere on the bottle there will be a sun shaped emblem.

I use Royal Purple Racing 41 which is 7w 40. Noticed a difference.

Gary

[raceman]

5W. is too low for our air-cooled engines including 5W-30 .That`s Honda Civic oil right there unless you`re driving at below zero temps.Mobil 0ne 15-50 or something similar for the vintage of your car is the most popular. l had been using the Mobil One but when l switched to a semi-synthetic my oil leaks stopped and my engine showed higher oil pressure.

[oliver88]

5w40 will work fine. original fill in the 80's and 90's was Shell Rotella 15w40....50 weight will not necessarily give better protection and may contribute to higher oil temps....0w40 is recommended and all Porsche engines back to 1973 i believe...remember the "5w" is the cold weather rating...will be a 40wt at temp...check out www.bobistheoilguy Used Oil Analysis section...many Porsches are showing outstanding wear rates with 5w40 oils...

[bigchillcar]

i'ved used castrol 10w40 for winter, 20w50 for summer for years..happy with it. i worry more about the heat in summer, as i don't have an aux oil cooler, so the 20w50 is a must. winter in arkansas is not extreme, so 10w40 works fine for me. i'd consider a non-synthetic 5-weight if i saw something i didn't like with my oil pressure/temps living up in the north tundra land. never heard of a 7-weight oil before, gary. have they been around a long time?
ryan

[Bill in OKC]

I have also been using Shell Rotella T 5W40 in my 3.2. The car had some oil leaks around the valve covers when I first got it - the PO had put some kind of moly additive in it too. The Rotella didn't leak any worse than what had been in there but then I replaced the valve cover gaskets during a valve adjustment and the leaks have disappeared. The valve train looked really nice and clean.

[lvporschepilot]

Use Shell 5w-40 with confidence. The base stock for America's Rotella T synthetic, Europe's Helix Ultra, and the oil cocktail Shell makes Ferrari for it's F1 engine's is the same group III Shell XHVI base stock. I used to correspond with one of Shell's tech guru's and he parted the clouds with rays of fabulous information. The above mentioned is some of the most pertinent.

The major differences between Rotella T synthetic and Shell Helix Ultra is the additive package, and that Helix Ultra is a mix of group III and group IV. I was told that the amount of group IV in the Helix Ultra mix is very low. It has enough to make it a legal synthetic in Europe. I was warned not to use group IV oils in an older Porsche motor due to it drying seals out which eventually causes leaks of course. I would not worry about Helix Ultra too much considering the low amount of group IV. Just my .02. Hope it helps.

Here is a quote from one of the correspondences you may find interesting:

There are two kinds of synthetic base stocks used for engine oils – Group III and Group IV. Properties and performance of the two kinds of synthetics are similar. The difference is how the synthetic is manufactured. ROTELLA T Synthetic is made from Shell’s XHVI Synthetic base stocks, which are Group III. This is the same base stock Shell uses for oil we prepare for the Ferrari Formula 1 race team.

one more quote:

I'm less concerned with molecules and formulations, and more concerned about performance. And Shell's Group III XHVI base stocks perform like Group IV base stocks do, at less cost.

But more important than base stock performance is performance of the finished oil. Oil additives play a huge role in performance. Best performance comes from oils with carefully balance formulations of high quality base stocks and additives. I guess this makes me a "pragmatist" and not a "purist".

To add to the discussion, I've copied below a previous post by Forum member BillXHVI, which provides a nice discussion of synthetic base stocks (I've slightly edited the post).

"It is true that ROTELLA T Synthetic is Group III (not PAO) based, but you must keep in mind that not all Group III base oils are created equal. ROTELLA T Synthetic is made with Shell's XHVI base oil, which unlike other Group IIIs does not begin as distilled crude oil, hence of all Group III base oils, XHVI is truly the only one that can legitimately be called "synthetic." XHVI is a wax isomerate, meaning that it is made from the slack wax removed from distilled crude in normal solvent dewaxing. This slack wax is catalytically transformed (isomerized) and hydrofinished into a chemically pure base oil which rivals PAO in virtually every category. There are other "synthetic" oils out there based on Group III, but Shell's is unique in that it uses XHVI base oil. Chevron and Petro-Canada produce Group III base oils that come close to XHVI, but even though these oils are all hydroprocessed and utilize the same type of isomerization technology employed in the making of XHVI, they are not the same thing. Only XHVI is made from pure petroleum slack wax and its CAS number is 92026-09-4. The CAS number for the more typical all-hydroprocessed Group III base oils is 64742-54-7. If you want to know what your "synthetic" oil is made from, take a look at the MSDS and look for these numbers. (The CAS number for PAO is 68037-01-4).

In brief, don't be so quick to dismiss Rotella T Synthetic as just another "synthetic pretender." It's made with the same base oil as Shell's Helix Ultra, and everytime you see Ferrari win a Formula 1 race, that's the oil in the engine."


Enjoy!

[livi]

Mobil 1 0w40 synth. All year. Works like a charm in cold Sweden.

Some engines leak, others don´t.

My no 1 priority is limiting cold start trashing of the internals. I figure the 0w40 should be a good choice with that motive. Most modern oils will probably do just fine. As long as they are fresh.

[red83911]

Thanks for all the feed back, I would not normally consider a full synthetic, but I do have the chance of a good deal on the Shell helix ultra 5w-40.

I think my main concerns are leaks, and also what the cleaning action of a fully synthetic oil might be on an engine that has run previously on dino or semi-synthetic. (Shell do make a big deal about the cleaning properties of Helix Ultra in their advertising). Where does all the washed out crud end up?
The viscosity I think should be fine for our UK climate.

Again thanks for all the comments, although due to my above concerns a still feel a bit cautious about making the change at the moment.

[bigchillcar]

'0' weight?? wow..never heard of one that light! where have i been??
ryan

[livi]

You kidding, Big Chill ?

Anyways, you gotta make allowances for my rookie status.

[chrisp]

Looks like you can buy Rotella-T buy the gallon and one place I looked it was $13.99/gal in packs of 6 gallon jugs ($84). That's $3.50/qt if you buy 2.5 oil changes worth. There's probably cheaper places too. That same amount of Mobil1 is $120.

[oliver88]

here's an interesting used oil report on some 0w40 oil from a Cayenne...i realize it is not a 911, but gives an idea of how tough newer formulations of so-called light oils are...

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=002842

[donstevens]

Originally posted by red83911

Where does all the washed out crud end up?

In the filter. Don't worry about it.

Don