Using Synthetic Oils in Air Cooled Porsches

[Lorenfb]

The article in the 5/04 issue of "Excellence" magazine may have resulted in
some confusion about switching to a synthetic oil in air cooled engines
which were previously run on petroleum based oils.

The article indicates that Porsche issued a service bulletin discussing the
use of a synthetic oil. A Porsche quote provided states; "Non-conventional
basic oils have more favorable properties as compared to conventional oils."
The article goes on to state that Porsche has "approved" synthetic oil for
all Porsche cars from '73 thru '98. It also states; "Porsche no longer approves
any conventional oil for any of these Porsches."

The statements being made can be interpreted in diifferent ways. The statement
about "more favorable properties" doesn't necessarily imply that's the case for
all engines, e.g. air cooled or high mileage engines. The article fails to state
what the more favorable properties are as they relate to various engine types.

The next statement about synthetics being "approved" by Porsche doesn't
state/imply that all engines using petroleum based oils should switch to
synthetics. It might, though, be assumed otherwise by the last quote of
"no longer approves" conventional oils. This last quote I doubt that Porsche
has stated for two reasons:

1. By making such a statement, Porsche becomes liable for any future legal
actions the result of engine failures in older engines.,
2. Porsche dealers still use petroleum based oils in the air cooled engines
and also the water cooled 928/944/968., and
3. Porsche gains nothing by recommending the switch to synthetics.

After having discussed the issue of switching to synthetics with many Porsche
independent shops and two major Porsche dealers in the U.S., the consenus is
that older engines which have been using petroleum based oils should not
switch to synthetics. Some I spoke with even went so far as to state that the
993 should use a petroleum based oil because of its' heat problems.

The techs I spoke with have indicated many problems with synthetics in older
engines, e.g. gasket/seal incompatibility, inadequate oil pressures causing
the oil light to flicker, additional oil leaks, and reactions with petroleum oil
residues remaining. Their feelings are not to switch unless the owner requests
it and always advise not to. Most techs indicate that there are few real benefits,
but many potential costs.

Therefore, the "Excellence" article raises many issues which can mislead
Porsche owners of air cooled engines. Before switching from a petroleum based
oil to a synthetic oil, the wise Porsche owner would give serious thought to
the costs and real benefits.

[araine901]

Why is is that Porsche swithced to Syn??

[svandamme]

1.how could Porsche be liable regarding cars that have been out of warrenty for more than 10 years???

any comment they do make , is a best effort they don't even have to make... of legal liability is the reason for anything, they might as well just stay mute and say nothing... cause they don't have to...

2. as far as my experience with Porsche dealers goes, i avoid them , since they don't give a **** about old timers. and do not have mechanics on board with the knowledge for them either...

[Wil Ferch]

In a related example, a "1973" owner's manua, or factory directive, might say the "most recent" service grade classification ( let's say it was "SC") is suitable. Today, with "SJ" oils available, Porsche might be tempted to say that "SJ" service classification oils should be used in today's cars, and can be considered retro-active back to 1973. They wouldn't say use "SC" in '73.... "SE" in 75, etc...today anymore.

I think a lot of this kind of philosophy finds its way into the synthetic vs mineral oil question.

As to lubricating / tribology characteristics ( only) , nothing beats a good synthetic. The reference to 993 engines requiring mineral oil because of heat is in direct conflict with the known characteristic of synthetic oils having much better high temp thermal breakdown characterisitics. It's particularly applicable to the upper-most piston ring which sees the hottest flame front, that cars running on syn oils show less ring and land groove wear than those running on mineral oil. The oil leakage question is intersting too...in that early formulations of Mobil 1 ( for instance) were so focused on oiling qualitites, they forgot ( or gave little thought to) the leakage tendencies. Only later formulations had the appropriate swelling agents to combat this. Still, even in my 85 Carrera, there is a marked tendency to develop oil leaks with Mobil 1 ( no matter how superior), which tends to heal itself after running some time on a quality mineral oil...
And so it goes.....
---Wil Ferch

[911SC Pilot]

I just read the same artical last night in my issue.

How about the comment thay used that talked about, when the older 911`s are changed to synthetic oil and you see all the new leaks, its not the oil causing the leaks, but instead, those leaks were always there, they never surfaced because of the thickness of the petroleum based oils, of which, help block the small leaks that will acure once you start to use synthetic. They go on to say, fixs the seals that are leaking and wa la, no more leaks, and you can run synthetic all you want.

[jluetjen]

Loren -- you have got to be a lawyer!

Eeeech

[araine901]

You would think he was the supplier of Bosch CD units to Pelican based on his previous postings. LOL

[jgporsche]

Once I used Mobil One in my 88 911 Cab, I've never regretted it. Even when I use the AC (Wife in Car) my temperature never gets up where it had with petroleum based oils. My 73 911S is a different issue. 80K original miles never been opened up, it drips and since I don't drive it a lot 20w-50w petroleum based oil works. If I re-sealed it, I'd probably use Mobil One and not look back. My 88 has 104,000 on it, no valve guide issues or engine problems. Probably just lucky! I guess!

[ChrisBennet]

Keep in mind that what I'm about to relate is the first time I've heard of this problem mentioned so just consider it a data point.

I mentioned to a friend that my 944 (170K miles) was making lifter noises. He asked "Are you using Mobil 1?" I told him I was. His 993 and a mutual friend of ours experienced/are experiencing this problem as well. He said a respected Tech we both know was switching his 944 and 993 customers back to dino oil because of these lifter problems. I don't know if he's doing this proactively or in response to actual problems on a case by case basis.

-Chris
EDIT: I talked to someone who works with that tech and my friend had it wrong. The tech has switched to Amsoil synthetic.

[Wavey]

Originally posted by Lorenfb
The article goes on to state that Porsche has "approved" synthetic oil for all Porsche cars from '73 thru '98. It also states; "Porsche no longer approves any conventional oil for any of these Porsches." This last quote I doubt that Porsche has stated...

"You doubt"? What are you saying? That Jim Pasha, the writer of the article, is wrong? You don't believe that Porsche has made the statement?

[i]The techs I spoke with have indicated many problems with synthetics in older engines, e.g. gasket/seal incompatibility...[/B]

This statement makes no sense at all.The gaskets and seals are made of one kind of material. There are not different gaskets and seals made for use with conventional vs synthetic. If you are rebuilding your engine, you buy a gasket/seal kit and it makes no difference which oil you use with them.

Your entire post is nonsense. It adds nothing to what is stated in the article, other than foolish conjecture.

[Jim Garfield]

So in this case you will accept word of mouth over factory recommendation, but regarding chips.....you seem to be consistently inconsistent.

[araine901]

Wavey,

think you will find that some of the gaskets that are now graphite coated or that green fancy pants stuff were in fact deliverd in many of the older air cooled cars in a simple paper form. I was told by andial that if I had upgraded to the newer style gaskets I could run synthetic oils if I chose to. I think the point is not everyone who owns an older air cooled may have upgraded gaskets yet.

[juanbenae]

you gotta love loren's ability to raise ire. i bet he would be all kinds of fun to watch in a bar. i imagine a cliff clavin sort, except shop cover-alls instead of the mailman suit....

[geof33]

Once again Loren...

I switched to Mobil1 when I first changed the oil in my car after purchase 7 years ago. The last oil change, went to Amsoil and initially thought I might be getting some ring blow by, and had a couple of "new" leaks. Retightened the various bolts to torque and VIOLA no leaks. Also, no smoke on initial startup. Temps run cool (never over 210-220)... I think I'll keep it!!

Loren is good at raising hairs...

[D Hanson]

I have thought about going to Mobile 1 on my 964, but my shop pumps Castrol 20W50 in the older cars. It does get hot and humid here in the summers. My concern is that my 964 with absolutely no leaks whatsoever may have a few leaks with the thinner Mobile 1. Am I wrong. Should I give Mobile 1 a try.

[geof33]

Originally posted by D Hanson
I have thought about going to Mobile 1 on my 964, but my shop pumps Castrol 20W50 in the older cars. It does get hot and humid here in the summers. My concern is that my 964 with absolutely no leaks whatsoever may have a few leaks with the thinner Mobile 1. Am I wrong. Should I give Mobile 1 a try.

You'll get all sorts of opinions... but I would say run the Mobil1. It really is an excellent product... and it is factory recommended now. If you develop some leaks, give them time and see if they stop. A drip or two, is no big deal. A little puddle needs attention. If your car leaks with Mobil 1 then the leaks have always been there, they just need to be fixed. When I switched to M1 I had no problems what-so-ever...

You'll also be smacked with the 3000m oil change debate. I go up to around 7500ish miles. Bruce Anderson states it is basically pointless to change a 911 oil after only 3000 miles, unless the car is run on the track frequently. He recommends the 7000-8000 mile interval. The quality of oil is too good these days according to him. Geez, even way back in the 80's (when oil was garbage) the factory recommendation was once a year or 15,000 miles...

[Jim Garfield]

Originally posted by k911sc
you gotta love loren's ability to raise ire. i bet he would be all kinds of fun to watch in a bar. i imagine a cliff clavin sort, except shop cover-alls instead of the mailman suit....

I switched to Mobil 1 at 48k mi. in a 3.2 two and a half years ago. The engine is bone dry, no seeping, no drips. It uses between one and two quarts every 5k mi. I couldn't be happier. YMMV.

[atlporsche]

it was posted on pelican...it's gotta be the truth...right?

sjd

[BGCarrera32]

Hey Loren, what kinda stupid browser do you use that all your posts show up about 3" wide?

[BGCarrera32]

Originally posted by Lorenfb
Their feelings are not to switch unless the owner requests
it and always advise not to.

There ya go again, using the F word...