jlkline

So, about 2 months ago, I bit the bullet after a lot of soul searching and reading forum threads on the subject, and changed to Mobil 1 (15W-50W)with about 11,000 miles on my completely rebuilt 3.2 motor. After around 3 months, it has begun leaking in various places including the valve cover gaskets (930 covers), bolts around the rear pulley, and other places on the motor, mostly at the rear. <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />

I'm looking for some advice on what corrective action I can take that will stop the leaking. Should I:

A. Stay with synthetic and change brands / or viscosities?
B. Go back to dino oil?
C. Other options?

KC911

I just updated a related thread on the Pelican site...On my newly acquired '88 (w/47K miles), I switched to Mobil 1 15W-50 six months ago (fully aware of the caveats for 'older' cars). Anyways, she never had leaked a drop up until a month or so ago when I began noticing an occasional drop on my garage floor (...i.e. a few drops per week). Anyways, bottom line is...I switched back to dino (Castrol 20W-50) last week, and she hasn't leaked a drop since!

scottb

My mechanic doesn't like synthetic oil in the older cars. He had me switch back to dino in my 84 3.2.

Bill Gregory

Although Porsche recommend synthetics for 1973 on, Allan Caldwell, PCA Technical Committee, says that SC's forward should be fine with synthetics. FWIW, I switched to Mobil 1 in my 81SC with 100K miles, and didn't have any leaks.

BER

I echo Bill's comments about Mobil 1. I have been using Mobil 1 (15W50) in my 1977 and 1984 911's for at least 10 years. The 1984 has never leaked (knock on wood) and the 1977 has a few drips every now and then (the '77 dripped dino oil before I switched to Mobil 1).

I have owned and been tinkering on 911's for 16 years and oil is a very popular topic among 911 owners. I think synthetic oils and 911's are a "love/hate" experience. Some people use synthetics and love them, others love their brand of dino oil and hate synthetics. As long as you keep the oil clean and 'fresh', you should use your favorite oil (assuming it meets Porsche specs). YMMV.

jlkline-in answer to your question, I would switch back to dino oil and see if the leaks stop.

Bruce

Brian911

After I had my tensioners updated my mechanic switched me over to synthetic 10-30. I have always been under the impression (after serving my time at a Jiffy Lube) that synthetics leak out quicker because they find that one little whole. The mechanic corrected me and said that the synthetic actually helps plugs the leaks by expanding the gaskets. In reality it has slowed down some of the leaks.

My .02

rfuerst

Here is my 2 cents with no real data to back it up,my mechanic,who has been servicing and racing Porsches for about 25 years says that they recommend that any Porsche 1990 or newer should run synthetic,any older run dino.I am not one to follow blindly just because someone says so but I trust this shop and I have followed the advice in my 1987 944S and my 1983 911SC.Having said that,I have a few tiny leaks in the 944 and so far the 911 is tight,would they start spewing synthetic if I changed?Not sure but I am not going to risk it. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

gerry100

I've got an '86 3.2 raised on dino and it has no leaks drips after 90k.

Outside of the issues debated in this and similiar posts I have a question?

If you are going to change every 3-4K miles why would you want to use an oil that is 3X the cost? are the operating advantages that significant?

Bill Gregory

I originally changed from dino to Mobil 1 when I was having overheating problems in my 81SC on the track, and needed the extra high temp protection of a synthetic. Have continued to use it since then.

jlkline

I went to the Mobil 1 site just now and looked up my engine and the recommended viscosities. (attached below)Interesting that Mobil doesn't recommend their 15W-50W for the 3.2 motor, and doesn't offer ANY full synthetic oil for hot climates for this motor either. I recall a post from Bill Gregory citing a tech bulletin for the Porsche recommended viscosities and brands, and the 15W-50W was on it, so I was sure I'd be fine.


So now, I'm wondering if a heavier weight synthetic would be the answer to the leak problems, and if so, which brand and what grades?


Check this out all you hot climate enthusiasts:

Right from the Mobil 1 Porsche pages


10W-30 -13° F to 68° F
You can use Mobil 1 with SuperSyn™ 10W-30 with confidence. This viscosity is also available in Mobil Drive Clean Oil™ and Mobil Drive Clean Synthetic Blend™.


10W-40 -4° F to 95° F
Mobil 1 is not available in that specific viscosity. However, 10W-40 is available in Mobil Drive Clean Oil™. Mobil 1 with SuperSyn™ 0W-40 or 15W-50 may be alternative viscosities. Please consult your vehicle owner's manual, or contact a dealer or your vehicle's manufacturer.


15W-40 Above 5° F
Mobil does not carry this specific viscosity. Mobil 1 with SuperSyn™ 0W-40 or 15W-50 may be alternative viscosities. Please consult your vehicle owner's manual, or contact a dealer or your vehicle's manufacturer.


20W-50 Above 14° F
Mobil 1 is not available in that specific viscosity. However, 20W-50 is available in Mobil Drive Clean Oil™. Mobil 1 with SuperSyn™ 15W-50 may be an alternative viscosity. Please consult your vehicle owner's manual, or contact a dealer or your vehicle's manufacturer.


5W-20 Below 14° F
Mobil 1 is not available in that specific viscosity. However, 5W-20 is available in Mobil Drive Clean Oil™. Mobil 1 with SuperSyn™ 0W-30 or 5W-30 may be alternative viscosities. Please consult your vehicle owner's manual, or contact a dealer or your vehicle's manufacturer.


5W-30 -22° F to 32° F
You can use Mobil 1 with SuperSyn™ 5W-30 with confidence. This viscosity is also available in Mobil Drive Clean Oil™ and Mobil Drive Clean Synthetic Blend™.

Chuck Harmon

I don't know what Matt says about synthetics but I run Redline 20/50 in my 83SC and have 248,000 miles.The Austin heat and traffic requires extra protection in my opinion.Vans sells Redline at a pretty good price.Good Luck

Bill Gregory

[quote]<strong>I recall a tech bulletin for the Porsche recommended viscosities and brands...</strong><hr></blockquote>
Here is the current oil recommendation from Porsche for all 4,6, and 8 cylinder vehicles from 1973 on:

Castrol/Syntec...................................5W-50
Mobil 1............................................. 0W40, 5W-40
Sun Oil/Sunoco Synturo Gold.................5W-40
Texaco/Havoline Formula 3 Synthetic......5W-40
Valvoline/High Performance Synthetic......5W-30

Viscosities recommended for the Turbo are 0W-40, 5W-40 and 5W-50. The latest Porsche bulletin revised xW30 oils top end temperature to 85 degrees, down from the previous 100 degrees. For outside temps greater than 85 degrees, xW40 or above should be used.

I use 15W50 Mobil 1 for dual purpose street/track usage.

Todd

The reason that synthetic "may" cause leaks is not only it's thinner, but it is a different kind of oil. It is a type of scavenger oil that will seek out deposits and hold them in suspension for the oil filter to clean. While this is excellent, all those little carbon deposits in your seals will be cleaned by Mobil 1 and thus cause leaks. Usually, going back to dino after this is too late. I run 10w-40 Castrol synthetic "blend" in my 73. It has the thickness and heat range I need, but offers a little extra protection without risking leaks with a full blown synthetic. I haven't used it long, but so far so good. I did put Mobil 1 in the 915 trans. I would like to switch to 15w-50 Mobil but am also concerned with leaks as it is completly dry now, and I would like it to stay that way. I think if you stay on top of the oil situation and change often dino in the earlier cars will be Ok. Tracking a car is different though, and you may want to go with a thick synthetic. Mobil 1 is VERY good stuff, and I've heard of racers putting in their "sponsors" bottle for ads because they want the ad revenue but don't want to use the oil they are advertising for. I use Mobil 1 in my newer cars and also some machinery I own. No problems.

Bill Gregory

[quote]<strong>I did put Mobil 1 in the 915 trans.</strong><hr></blockquote>
Mobil 1 synthetic transmission lube is typically considered too slippery for a 915 transmission (while being better suited for the G50's syncro's). Swepco gear lube is the general lube of choice in 915's.

How have you found running Mobil 1 in your 915?

jlkline

Todd,

Your points are well taken for a higher milage engine, but I don't think applicable to my situation. With only 11,000 miles on the rebuild, and 3 oil changes up to this point, there would be very little in the way of deposits in that motor. Even the magnetic oil plugs were fairly clean as observed during the 3 oil changes.