Shell VS. Mobil One, opinions?

[sammyg2]

I went to Wal-Mart today to search for those elusive Mobil-one gallons for $12. no such luck. They did have the Shell fully synthetic oil for $13 a gallon though. Any thoughts or opinions on that oil?
BTW it is 15-W40.

[philfran]

Haven't used the Shell, Mobil 1 only, but I don't think the Shell would be a problem. I am sure some will swear that it is the best and then other will say that your motor will self destruct within 30 seconds with Shell!

I would stay with 10W50 instead of the 10W40, esp. in hot weather. Remember, heat is your enemy and consistent oil viscosity is your friend!

[jmohn]

This is semi-related to your question. I'm using Shell, but not the synthetic. I'm using Shell "Rotella T" 15-40, I switched to it awhile ago. I always used Mobil 1 in my 951 (I thought it was a good idea, that turbo can get HOT), and initially used it in my SC also. I went to the Rotella just because: the SC never runs hot, I change at 3000 miles (I like clean oil and I do not believe in extended drain intervals), the 15-40 falls within the recommended viscosity, the Rotella is a very high quality oil, it's available at any truck-stop and, lets face it, it's cheaper. My oil pressure with the Rotella 15-40 is the same as it was with 15-50 Mobil 1 (just over 1 bar per 1000 RPM). Certainly, if you track your car or it typically runs a little hot, I think synthetic gives you a little extra protection but for a "daily driver" I think a high quality dino-oil is just fine.

Cordially,

Jerry M
'78 SC
(PS the Rotella comes in 1 gal. containers)

[pwd72s]

Jerry? Isn't the Shell Rotella made for diesel engine use?

[tdorsey835]

Regarding this never ending oil debate... I am using Castrol 20w50 in my 89 Carrera with 156k miles. If i switch to Mobil 1 now, will it cause leaks?

[stormcrow]

I switched to the Shell Rotella recently after I had the belt break on the engine. Luck for me no engine damage. Since I have been uning the Rotella, my valves have quieted down some.

I was concerned about using it because it's for diesel engines, so I sent a e-mail to the mfg. This is the reply I received.




Presently drive a 78 911 Porsche. 3.0 L Engine. Engine just rebuilt at 81,000. Presently have 20,000 since rebuild.

Have been using Valvoline 20W 50W. Recently switched over to Havoline 10W 40W and have just this last oil change switched to Shell Rotella 15W 40W.

There is concern from other Porsche owners who I correspond with that the Rotella is only for Diesel Engines and not good for Porsche engines. Is this the case? Please advise.

thanks.


Steve Kowak


Steve -

Thanks for the opportunity to respond to your inquiry, and thanks for your
interest in Shell ROTELLA T Multigrade.

ROTELLA T SAE 15W-40 is a universal oil, meeting API Service Categories CI-4 and SL (CI-4 for diesel engines, and SL for gasoline engines). Where the engine manufacturer recommends either one (or both) of these Service Categories, or earlier categories, ROTELLA T can be a good choice.

Some passenger car engine manufacturers also recommend oil meeting requirements represented by the API Certification Mark (API Starburst). ROTELLA T does not qualify for the API Starburst. If the Starburst applies, it would be to recent model Porches - it would not apply to your 1978 model.

Consideration should also be given to recommended SAE Viscosity Grade. For fuel economy purposes and very cold temperature performance, passenger car engine manufacturers usually recommend lower viscosity grade oils than SAE
15W-40. Again, low viscosity grade oils are usually only specified for late model gasoline engines.

The more robust performance of ROTELLA T compared to current passenger car oils makes ROTELLA T an excellent choice, specially for earlier model Porches. Better extreme pressure wear control and better deposit control are pluses for ROTELLA T.


Peter Van Benthuysen


Tel: +01 281 544 8253
Email: Peter.VanBenthuysen@shell.com
Internet: http://www.shell.com

[pwd72s]

Sounds good to me. Besides, even if you're using the wrong lubricating fluid, it is better than not any, or not enough...I have a friend who swears by the Mobil brand of diesel oil. And what the hell, his cars do live long. None of them are 911's, but they do live long.

[TimT]

Rotella is the "million mile" motor oil......

It is always reformulated to meet the latest specs.

Rotella is a great oil!!!

fleets use it..... I use it.... its a good thing

[jmohn]

pwd72s:

Rotella T is a high quality, multi-purpose, multi-grade oil; it meets or exceeds all current specification requirements for gasoline or diesel engines (excepting some propriatary diesel usage, I think). Actually, diesel engine oil spec's are more stringent, and an oil that meets requirements for both gas and diesel (and is rated for use in both) is quite high quality. If you're interested, check this site:

http://www.rotella.com/products/rotella_t.html

and, of course:

http://www.pelicanparts.com/techarticles/mult_gas_and_oil/mult_oil_article.htm

Cordially,

Jerry M

[jmohn]

Originally posted by tdorsey835
Regarding this never ending oil debate... I am using Castrol 20w50 in my 89 Carrera with 156k miles. If i switch to Mobil 1 now, will it cause leaks?

I guess I'd have to ask, why change? While I never experienced the problem myself, there is anecdotal evidence of older, higher mileage engines leaking more after switching to synthetic. Unless your engine (due to track usage or extremely hot climate or ?) needs the added protection of a synthetic, just continue to use a good quality dino-oil. I would suggest changing more often than the suggested interval, higher mileage engines (even though running well) generally dirty the oil more quickly due to an (almost certainly) increased amount of blow-by.

Jerry M

[J P Stein]

For a turbo motor, I'm a firm beliver in Mobile 1.
It's high resistance to coking is the big plus.

Upon tearing down a couple of 911 engines, I found the all the ring grooves of both had carboned up pretty badly. The undersides of the pistons were in similar shape (both had squirters,btw).......hummm. I can help minimize that, me thinks.
The new motor gets Mobile 1.

Sometime in the distant future (hopefully) I'll get a look at these pistons and report back.

[jmohn]

Originally posted by J P Stein
For a turbo motor, I'm a firm beliver in Mobile 1.
It's high resistance to coking is the big plus.

Upon tearing down a couple of 911 engines, I found the all the ring grooves of both had carboned up pretty badly. The undersides of the pistons were in similar shape (both had squirters,btw).......hummm. I can help minimize that, me thinks.
The new motor gets Mobile 1.

Sometime in the distant future (hopefully) I'll get a look at these pistons and report back.

Yes, I should have included turbo-charged cars in the exceptions in my previous post. If it was a turbo I would (and did, when I had one) use synthetic oil. I was, however, responding to a question about an '89 Carrera (no mention of a turbo).

Jerry M

[J P Stein]

I should have been more specific.
The 911 motors were NA.

[feelyx]

I think the factory orginally filled the engines with Shell oil also...
Tim in Sac

[David Ceruti]

I changed to Shell Ultra (full synthetic) 5w40 on my 50k miles 3.2 a few months ago. So far the engine sounds good, no leaks and no oil consumption - the level on the dipstick hasn't moved in 3k miles.

I went to the Shell because it was more affordable. Also the car was originally filled with Shell and the F1 endorsement didn't hurt

[Ted Stringer]

After rereading my post, yeah it is somewhat OT

The Rotella T oil is also good for use in turbos. Many of the semis are have turbos and still use Rotella T. Both of my diesels have it, and diesels are harder on their oil than any engine that I know of.

The only thing is that diesel exaust is cooler than gas. This comes from a more complete combustion in the cylinder, enabled by the ignition style. Turbodiesels only need to be idled for 10 - 15 seconds before shutdown (unless you have been sitting at the redline for the last half hour).