Kiln_Red

Don't have their MSDS. Don't need it. They (Mobil 1) claim a minimum of 1200ppm on their site. Can you tell me why I shouldn't trust them.

Bjbpe

Sure wish I had some of you guys around when I was taking Organic Chemistry 101 about 52 years ago (believe it or not I did get an "A" in the course). Seriously (when am I not serious when it comes to maintaining my 928S4) I have the impression that, since my engine virtually never goes north of 4000 rpm (and I preserve my wallet by not burning rubber or driving much above the speed limit in Wyoming) I should be OK just using Mobil 1 15w-50. If there is a special additive available at one of the usual car shops or WalMart that someeone can recommend, I'll buy it.

SeanR

Maybe you should read up on it a bit more. No where on their site does it state what you just posted.

Here is the chart.

http://www.mobiloil.com/USA-English/...duct_Guide.pdf

BTW, no one has told you not to trust them.

Kiln_Red

Someone must have answered this question here

Not trying to ruffle feathers, Sean. Just looking for further education as it appears others are as well.

curtisr

"Porsche do not recommend a diesel oil in a petrol powered engine , not last century & not in this century. Now why is that so ?
Answer = primary diesel oils are very high in detergents( compared to petrol powered oils) and these detergent packages tend to make engine oil foam too easily , so they then add silicon to reduce this tendency , but detergents attack the ZDDP , thats why primary diesel oils look as if they have very high ZDDP( new) , but as time goes by the ZDDP is damaged by the detergent packages .

Now back to the foaming , if a petrol engine from last century revs harder to make its max power as opposed to a diesel engine from last century ( like for like) this in quite normal , so in a big rig that cruises on the freeway at 1,800 RPM will give the oil way less tendency to foam as say a sports car / GT engine that is being revved to 6,500 RPM a lot .

This is where it gets interesting , foaming / air bubbles in the oil is the VERY last thing you need in a 944 / 951 or a 928 , because they have a very small flaw in their crank oil feed design , they starve no 2 con rod bearing ( 944 / 951 / 968 ) and 2& 6 con rod bearings on a 928 if the oil pressure drops to low."

"...the only thing that works is a 20w-50 ( never fails ( so long as the engine is not already badly damage by running around with a low vis oil."

I hate to be so dumb but, doesn't the above represent a contradiction? Sure, the last bit is presented in the context of high-core temp conditions; however, on the one hand I think I am being told not to use 20w50 and on the other, I have the expert's blessing???

When I look up diesel oil I find that manufacturers such as Amsoil and Valvoline say that their 20w50 is fine for both diesel and petrol engine applications. I admit that I don't find such a recommendation in my Owner's Manual; however, that is the crux of the matter isn't it? Today's diesel oil = last century's petrol oil n'est pas?

As for the foaming, I've yet to see that while running Rotella diesel oil.

Charley B

How have you accomplished observing foaming, or lack thereof, while running Rotella?

uraniummetallurgist

A useful link for more information on zinc dithiophosphate - what it is and what it does.

http://en.wikipedia.org/wiki/Zinc_dithiophosphate

ROG100

Austin,
It is pretty simple in my book - Mobile 1 does not state what level of ZZDP it puts in its oils at any one time. They changed the level when it was known to effect the performance of a cat. They changed it back again. That is called "Flip Flopping" and I for one need something more reliable than that. There are oils out there that cost a little more but maintain the correct level of ZZDP. I chose Royal Purple because they are consistant about exactly what level of ZZDP is in the bottle.
As I only change my oil every 12 months of 15,000 miles the additional cost v the peace of mind is tiny.
I have about 16 928's and they all use Royal Purple. Apart from the one in the UK which will be changed once it reaches these shores.
I listen to real stories from people like Bruce Buchanan who has worked on more 928's than I have had hot dinners.
You pays your money you takes your choice.
Best,
Roger

waynestrutt

You live where the best crude stocks in the world come from. Use any 20-50 pennzoil , pennstate, or other brand with penn. crude source. Acid is the worst enemy of your engine and crude from your state has the lowest sulphur content so acid levels are low. At Gulf oil whenever a delivery of penn crude stock was coming we new we were going to have an easy week of refining,,... practically refined itself. Do not use stp as it clogs the small passage of the wrist pin and oval bores can occur.

Kiln_Red

Is there anything out there, for the rest of us to see, that substantiates these statements? That is all I would like to see.

77tony

Mobil 1 chart http://www.mobiloil.com/USA-English/...duct_Guide.pdf
I'll stick with the M-1 15-50. T

linderpat

whew - I was hoping this wouldn't turn into this

I was just bemoaning the lack of info on the label, making it hard to determine what brand to buy when at the auto parts store. I have read just about every oil thread over the years on this board too. there is lots of good information on this here. I use Castrol GTX 20-50 or similar, but when that isn't available, I like to know what the alternatives are, while looking at the jugs on the shelf, and not have to waste time and run home and do a research project.

I think I'm convinced that finding and sticking with a local Royal Purple rep will be the way to go. There is one that lives not too far from me.

Leon Speed

Ed, if I can't find it on a spec sheet on the website, I email the manufacturer and usually get a reply.

Kiln_Red

Ed, rest assured that I am not participating to pick a fight. Just looking for facts. I wouldn't make this conversation about anything else. I appreciate and respect Roger for his part to keep the 928 alive and thriving.

If you are at all under the impression that my questions are muddying up your thread, I am happy to continue this conversation with Roger privately.

linderpat

Not at all Austin, and I wasn't referring to anyone in particular - you are all very knowledgable add quite a bit of depth to these threads. I was just referring to how these oil threads invoke so much passion. I thiought this would be a short one about bad labelling.
Carry on all