well, of course when this thread heats up, the BITOG forums go down. I'll have some links for you fellas when they come back up. Many on there believe that M1 is still PAO not GIII based, but I did read what L77 said about talking to ExxMo guys.

I just sit on the sideline and watch, I use a real synthetic, Redline. I imagine everyone using AmsOil find this discussion amusing also. Never had any leak issues either. Maybe Royal Purple is the real thing too?

Lubemaster, why did you say this just a month ago?:

In this thread, bottom of page 3:

http://forums.pelicanparts.com/showthread.php?s=&postid=2062366&highlight=mobil#p ost2062366

My personal experience when changing to full synthetic is that my car started leaking.

It was clean and did not leak at all before, but after it started to leak. It also leaves a puff of blue smoke on startup (or at least more than with the dino oil and only after not driving for at least a day or three), which bothers me more than the drip of oil.

I know I'll be trying a semi-synthetic soon.

But I do believe that some people have done it without leaks, so just try... it doens't hurt (apart from the oil filter and oil cost).

Yes I tightened the one on my left and now my head hurts no longer, thanks for the tip.:D

As Navaros911 pointed out my biggest complaint was the blue smoke. As I have mentioned it is a non issue now with the dino oil. Although as mentioned in lubes thread my temps are hotter.
Am I correct in assuming that the syn leaks down past the valve seals.
My 86 with 120k miles is on mobil 1 and tracked pretty hard with no smoke although a few leaks, this puzzles me.

Koboltblau - man! I feel like John Roberts! Actually, the Mobil 1 is based on PAO's but...

They were 100% when they first came out, and may even go back due to the increasing costs of III's.

I am actually flattered that you not only found that quote but actually must have done some reading of my oil rants!

Yes, Sir. people on the BITOG forums say that the new mobil clean 7500 is a Group III / PAO blend, but most don't think that the "regular" mobil 1 has Group III base stocks at all. Now we have another variable with the "extended performance" which is all the 15w-50 comes in anymore, as I'm sure you know.

Cheers,

FWIW - I switched my 137k 87 to mobile 1 about 3 months ago. no leaks with dino before and still no leaks with the new mobile 1 extended performance 15w40. coincidentally, my oil consumption seems to have gone down and the car is running cooler. just another data point for you. I just drive hard on the street - no track "yet"

I had heard about this Consumer Reports article on their test of New York City cabs and found this link below. It's from '96 but Mobil 1 was avail. at that time. The test seems pretty extensive and exhaustive. You can argue that your driving conditions differ from a taxi's (or are more grueling). But these guys drive their cars like there's no tomorrow and since they rarely own the car they're either all gas or all brake. The lack of frequent cold starts and short trips are what is unique to cabs but 911 probably don't don't get that treatment either. You could argue that 911s are exposed to more "extreme" driving conditions because of the temperatures they can get up to (like when your needle approaches the line at 3/4) driving around w/the A/C on or at the track.


http://www.xs11.com/stories/croil96.htm

It may be that Mobil 1 still uses "some" PAO....we just don't know how much. If you've followed the performance specs shown by the independents ( as in the "oil bible" among others)...you will see that there is a general "dumbing down" of Mobil 1 over the years.

OK...so Mobil 1 might not be 100% PAO anymore..but the base stock might not be 100% group III either...but a blend.

US law really allows both these things....non PAO to be labelled "100% synthetic"....and any normal oil with 1% synthetic to be a "synthetic blend". Human nature....being what it is...assumes a "synthetic blend" to be 50 / 50. Nope.

Interesting how the motorcycle version of Mobil 1 shows considerably better flash point and HT-HS compared to "normal" Mobil 1. Might be more than marketing hype...when the cycle version costs about 2x as much as the car version, too.

As I said... I like the Shell Rotella-T 5W-40 synthetic ...known to be a Group III. I don't have leaks like ( early?) Mobil 1 and it has good performance numbers like good HT/HS and FP. I don't care about low temp cold flow because the 911 doesn't get driven in the winter.

Wil

Wil - motorscooter oil is different than auto oil - has to pass different specs. They can call it anything they wish but it doesn't surprise me that it is differnt (as is marine oil).

Not to hijack the thread too much, but please elaborate, L77. In my moto, does it make a difference if I run "regular" Mobil 1, or do I have to buy the more expensive bottles with the picture of the motorcycle on the side? Or does the answer to that depend on the type of motor/type of riding I'm doing?

Mine has enjoyed synth the last couple of years. Changed last time in November 2004 to Mobil 1 and went with 0w40. Since then driven about 2500 miles. No leaks, very little smoke.

´85 with 87k miles never opened.

LubeMaster : I chose 0w40 on account of the cold winters in Sweden - want to drive it at least once a week in winter - and reckon would be good for stone cold upstarts in winter. Too drastic choice ? Wrong thinking ? Dead stupid ??

In many motorcycles, the engine oil also is used to lubricate gears and as a power/torque fluid in the wetbrake. This may not be the case with all. If the oil does have multiple applications, it will have to have a robust anti-wear pack (which most engine oils do) and anit-foaming nature but it must also have a rather interesting balance between providing enough friction to hold a clutch and also enough lubricity to reduce friction.

livi,

The most important thing for cold starts as I understand it is the pour point of the oil. Synthetics normally substantially out-perform non synth in this area.

One thing that is interesting to note is that the pour points for synthetics aren't always closely related to their weight. for example,

mobil 1 0w-40 pour point -54C
mobil 1 extended performance 5w-30 -45C
mobil 1 extended performance 15w-50 -42C

by comparison,

mobil clean 5000 (nonsynth) 5w-20 -39C
mobil clean 5000 (nonsynth) 5w-30 -33C
mobil clean 5000 (nonsynth) 10w-40 -36C

so you'll see that even the M1 15w-50 has a lower pour point than the 5w-20 dino.

If you have no leaks, I think the 0w-40 will work well year round for your climate. I use the 15w-50 so that it is OK for high temperature track events, but this is in dry 5200ft altitude at 90+ degree ambient temps. Even at track events in sweden you won't get these conditions so I would not worry about 0w-40.

Cheers,


So as you can see, you probably would be OK with