Two things....
- I believe Mobil 1 does indeed have a swelling agent installed...the earliest formulations didn't and the reputation for leaks developed. Later formulations of Mobil 1 apparently addressed this...so how was it done if no agents were added?
- don't get sucker punched on the high temp characterisitics of Mobil 1 as "always" being superior. The Mobil 1 formula has been "dumbed-down" over the years...and many single weight dino's ( especially single weight 30 or 40 or 50) have much better high temp characterisitics ( Flash point and HT/HS numbers....high temp/high shear).

See related post on oil web site I found ( "oil bible").....for details.

http://forums.pelicanparts.com/showthread.php?s=&threadid=188311&highlight=oil+bi ble

Wil

I've had similar experience when switching to Syn - cooler temps and serious leaking. Switched back to Dino and about 12 months later the leaking stopped?

I switched to mobil 1 15w-50 early this year. My car had 113k miles on it at the time, but virtually all new seals. Well... it took about 6 weeks, but eventually a seal that apparently hadn't been replaced developed a leak onto my exhaust that made for some nasty smoking. Switching back to dino oil had no (or not enough) effect. $700 later, I'm all set and I'll never put synthetic in a used car again. Honestly, ask yourself what problem you're trying to solve here and if the expected payoff exceeds the risk you're running. If you track the car frequently, it might be worthwhile. If it's a street car that is occasionally driven with enthusiasm (my case), it probably doesn't make much difference. After 119k on dino oil, my car still shows nothing on the drain plug magnet when I change the oil, is still on its original turbo, has perfect compression, and the motor has never been opened (top or bottom).

1. I am a bit confussed, how can you have "virtually all new seals" and yet never been opened (top or bottom)?

2. Which seal was the $700 one, sounds a lot like mine, shows up when it wants to.

3. Dino rules!SmileWavy

I have a 951. The only seals that were original were the oilpan gasket, head gasket, and the cam tower gasket. It was the cam tower gasket that went, which involves removal of the timing belt and cam tower, hence a 7.2 hour stay at RPM Racing to the tune of about $700 (on the high end for this job). It's a shame, because the car had a timing belt job in January right after I switched to synthetic. If it would have started leaking immediately, I could have had it done for only 1 extra hour of labor. :(

Re: Made the move to synthetic....
 

Was your horn louder too? Sorry, evidently your hearing has improved somewhat with that oil conversion. ;)

Terry, I am not sure why I feel the exhaust is louder, maybe the engine reving more freely with the synthetic? Could be me but I pick up on everything, I should have been a detective...my wife hates it!

Where do you see evidence of this?

From the Mobil1 site:

"<b>Will Mobil 1 will leak out of the seals of older cars?</b>

Mobil 1 does not cause leaks. In fact, new Mobil 1 with SuperSyn™ was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made.

<i>ExxonMobil engineers are wary of conventional oils that tout their use of additional seal-swelling agents.</i> With extended use, these agents can over-soften engine seals, resulting in leaks. More to the point, an oil additive will not rejuvenate worn or damaged seals. The damaged seal may have been caused by a worn rotating metal component in the engine.

If an older engine is in good condition and does not have oil leaks, Mobil 1 with SuperSyn™ provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1 with SuperSyn™. ExxonMobil also always recommends following the automobile manufacturer's manual for the proper oil to use.

Rick:

I understand your point. The web site says ( as you show):

Mobil 1 does not cause leaks. In fact, new Mobil 1 with SuperSyn™ was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made.

It is known that ( for whatever reason, lack of swelling agents, etc)...the *earliest* formulations of Mobil 1 ( maybe even when it was known as Mobil SHC...Synthetic Hydrocarbon oil in Europe) did cause leaks and the statement above indicates the formulation was changed for this not to happen anymore. Perhaps we're splitting hairs if we call this formulation change as simply a change in make-up, or specifically adding other ingredients that cause seals to swell. In either case Mobil 1 today is different that the older formula...and should not ( by itself) be the cause for leaks.....

Wil

Ok Wil, I get where you're coming from. So, do all dinos have seal swelling additives? Seems people here swear that (most / all?) Synthetics are causing leaks.

I've asked the question before. Why doesn't Mobil add these agents to stop the "myth"? They'd probably (re)capture a large segment of the enthusiast market. Members here have tried it and probably would love to continue using it, yet drop like flies as they see leaks start(?) or worsen.

.....just spouting off a bit...hope you don't mind

If I may interject on this discussion on Mobil causing leaks....I do not believe that Mobil causes leaks however I believe the cleansing properties of synthethic oil will cause a plugged hole (by dino oil build up) to open up. It will litterally clean away an oil cork and begin to leak. This is my theory, so a very tight engine to begin with that never really had any bad leaks will not begin to all of a sudden leak, however an engine that does have some leakage problems that became gummed up over the years with dino sludge will begin to leak with the new synthetic oil. This is why I believe we are getting two sides of the story here from different members.

As a data point, in my '88 (w/ 47K on her at the time), I switched from dino to Mobil 1. My motor was spotless, so it was easy to detect when the leaks began several months later (plus, a drop or two would eventually make it to my garage floor). It also took a few months for the leaks to cease after switching back to dino. My car rarely climbs above 210 degrees, so that's never been an issue.....I would use synthetic if it weren't for the leaks :(.

The point 1982911sc makes is correct...that's why I said "of and by itself" Synthetics don't cause leaks....yet for many ( me included) this is exactly what happened once I used Mobil 1 for any length of time...especially in cold weather. I also believe the cleansing properties are the "cause" of the leaks.

The other irony is that ( as I had held as "true" for so long ...but it is false) synthetics are universally thought to have better high temp characterisitics. Surprise...some mono-weight ( 30 , 40, 50) dino oils actually have much superior flash-point and HT/HS ( high temp/high shear) characterisitics. But you hafta look and find out which!

Wil

Wil,

Full synthetic (Wal-Mart $12.87 Gal.) I use it in the TDI.

Tony

I've also posted my frustration in that my "local" Wall-Marts no longer carry the value priced 5 qt containers of Mobil 1 15W-50. Whenever I ask I get...." Waddya need that weight for?...only good for racing! Slow mover."

/groan/

Wil

Here's what I don't get. What the heck is everyone all worked up about a couple of drops of oil on the floor? Get a drip-tray or something. It's a car, with very complex and highly stressed mating surfaces, of course it's going to leak!

I don't get it. To me the benefits in protection to my expensive motor FAR outweigh a drip or two on the floor.

But that's just me I guess...

I think you're missing an important element in these discussions, tiorio...

Sure, you could agrue that you'd tolerate the oil drops for the extra protection afforded by synthetics...but if you look up some data like on the oil bible web page I posted, you can find mineral oil ( mono weight) that has up to 100 degrees MORE high temp and high temp shear protection than Mobil 1......so why do Mobil 1?

There are boutique oils like Amsoil ad Redline that have better specs than Mobil but cost twice as much too...like $8 / qt. These also have 500-550 degrees flash points like the 40 or 50 weight straight oils....but now the price spread is even greater.

I submit that you can go with a super-refined ( cracked) oil like Shell 5W-40 synthetic ...which so far has not leaked on me but maybe because it *may* not be a true PAO synthetic like Mobil...OR...go with a 30-40-50 single weight oil with great specs ( cheap) if you can tolerate the single weight ( as Porsche recommended for many years up to the late 70's).

Wil

Having done an oil change when it was around 0F last year, I can attest to the wonders of synthetics. The dino oil I used was 5W30 and I had to put it in the oven to get it to come out of the bottle. It took about 3 minutes to empty a quart into the funnel. That was about all I could stand before I went inside to fetch the next bottle out of the oven. The little bubbles were suspended like fruit in jello when it was barely moving through the funnel. This was a light weight oil as well. It took an hour to drain and fill my toyota. Nuts. Synthetics are where it is at in the colder climates.

The Factory recommendations as of Feb.28 '03...

"For ALL Porsche models from 1973 onward the approved U.S. oils are: Castrol Syntec (SAE 5W-50), Mobil One (SAE 0W-40, SAE 5W-40), Sunoco Synturo Gold (SAE 5W-40), Havoline Formula 3 Syn. (SAE 5W-40), and Valvoline High Performance Syn. (SAE 5W-30)."

I don't have a dog in this fight, but I think that it's interesting that the factory only recommmends synthetic oil for all cars produced after 1972. And why only the cars after '72?? :confused:

I have used a synthetic/dino mix since the maybe 1987-1988 with no problems. I have mixed 15-20% syn oil with the dino stuff and have never increased oil leaks, oil usage, nor any problems (in my experience). I actually read of doing this in Outdoor Life (I believe) on an article on winterizing your car. The article said, mix 1 quart synthetic with 4-5 quarts for a cold cranking advantage. I truly believe in synthetic oils being an advantage, but ONLY if they do not cause other problems. My company runs several large turbines 24/7 and these run 7-15000 hp, We have data that proves syn oils work for us. That aside, we get most wear in our cars on cold start-ups. That is where I see syn oils having the advantage in our cases. My car sits for weeks sometimes, synthetic oils cling better and coat suffaces better. The down side is, (while they lube better for longer) once they start breaking down, the deterioration is pretty quick, not like slower deterioration of dino oils.
I can provide more printed info of our results using Royal Purple, and sometimes Mobil one compared to records of dino oils, again over many years of recorded vibration and wear engineering studies. In our case, we use only synthetic on our most needed equipment. No slight on dino oil, but synthetic works for us.
Now,
I asked our service rep the mixed oil question, he called their metallurgist (Royal Purple) and handed the phone to me (told me not to quote him). Was told, they prefer to sell syn oil. Later admitted, you get near 95% advantage of syn oils in a proper mix (80-85% mix). He advised 100% syn.

I have mixed mine for 17-18 years. No extra leaks, no more oil usage (actually I have not had an engine that uses any oil except my Porsce in those years), and that is little.

I added 3 quarts of synthetic at my last oil change on my 84 3.2 and have not added, nor seen a single drop leak since January.
I only know what I have seen, and experienced. In huge turbines that run 100% capacity, syn oils work great (but may sometimes leak). In equipment that runs 18 months between shutdowns (24/7) I cannot prove leaks would be better with one oil or the other, but I believe syn oils do leak worse. Heck, if my big turbines leak 5 gallons/day, we keep them running and add a barrel every week+. Both oils are good, but we run equipment longer at 3900-4000 rpm on synthetics.
Try 4000 rpms for 18 months on you Porsche, I do this on several turbines (many only run 3000, or 3,600 rpms) for these months. Synthetics are valid, but not THE answer for everybody. I still use the blend till I see a problem. I could go on and on, will spare ya...