Is it possible that an oil change can stop a leak?

JeffreyNMemphis · 03-23-2007, 01:34 PM

Hello Pelicans,

The PPI on my 1985 Carrera coupe found oil leaking from the oil return tubes, the oil pressure switch and O-ring. I changed the oil yesterday after cleaning the engine down to bright shiny dry aluminum. From the previous owner's reciepts, it would seem that his last oil change was 12,000 miles ago with dino oil. I cleaned a good bit of sludge off the drain plugs and the oil was black.

Is it possible that by putting in Mobil one 15w50 that the car might stop leaking? 24 hours after the change, I don't have a drop on the ground and the engine case is dry at the oil return tubes.

Also, I thought it might be a good idea to change the oil filter after the first 500 miles, just in case I stirred up a bunch of dirt that didn't drain yesterday. Any thoughts? I used a Mahle filter this time, but I am thinking about trying a Mobil One synthetic filter (good reviews on the M1 filter can be found here on Pelican).

Thank you for your thoughts!

troy jones · 03-23-2007, 02:03 PM

have you driven the car since you changed the oil? Once you've put some pressure on the system youu'll probably know better about your leaks if none show up great. if they do, at least you'll know where they all are. changing the filter at 500 is probably a good idea as the oil was pretty dirty.if it was that dirty you may consider changing the all of the oil then as the filter can only pull out so much of the sludge that the new oilis picking up. personally i'd do that until my oil looked clean upon checking it every 500 if it's really dirty you can use a cheaper oil for a cycle or two and then put the mobil 1 in once you know your systems clean. both are good filters. I use the mahle because of the high flow rate it's supposed to have. do a search there are a lot of really good threads on oil here.

sergeshishik · sergeshishik's Garage

the previous owner might have hastily dumped a bunch of oil in the car and spilled it in the engine compartment. I have done this and the car can seem to "leak" for days. But a nice long drive will give you a clearer picture on your oil leak concerns.

JeffreyNMemphis · 03-23-2007, 06:28 PM

This is my first 911... I have so much to learn. I didn't know how to check the oil when I was looking at this car with the previous owner. Scary thing is, he owned it since 1999 and didn't know how to check it either. Could he have spilled some oil in the engine compartment? Probably. The motor was filthy with oil, but I cleaned a lot of it. I could easily spend another eight hours detailing the engine compartment.

The car had a puddle under it when I went to see it. The previous owner was not aware of any leaks, but in general, he way overstated the condition of the car. The "new tires" were purchased in 1999 and had dry rotted. In the last 3 years, he put less than 1,000 miles on the car (according to the invoices that came with the car).

I wonder if it could be possible that several/many cycles of the engine heating up and cooling off could make the gaskets and seals start holding again? I have heard that if you let the car sit too long it is bad: bad = leaks?

TerryH · TerryH's Garage

I'll go out on a limb and say if the car was leaking before, it still is leaking. However, some have claimed that when they started using synthetic oil, it created a leak where there wasn't prior. Keep your fingers crossed and maybe it was just spillage or seapage from sitting so much.

If the previous owner neglected basic maintenance, I would have used dino oil and changed it again after 1,000 miles to flush out any crud that may be starting to build up.

the · 03-23-2007, 07:54 PM

Mobil 1 *stopping* a leak. That'd be a first!

SP2 · 03-23-2007, 08:15 PM

Yes, absolutely. My 993 had Mobil 1 0w40 in it. That was the factory recommended oil. I had a few drips from the valve covers. I asked Steve Weiner about this and he recommended M1 15w50 for Seattle, which is similar to his Portland. And he said the drips would probably stop and they did. John Walker changed my oil and did a tune up, but didn't do anything to the engine (no valve covers off, etc.) I suppose it is a viscosity thing.

sergeshishik · sergeshishik's Garage

In any case, you should plan on changing the oil return tubes, those o rings may tighten and stop leaking, but once you start driving it they are sure to leak again. It is a fight to replace, but can be accomplished with little skill, and it is relatively affordable. Tons of posts on this site with tips.

rbuswell · rbuswell's Garage

Quote:

Originally posted by sergeshishik
In any case, you should plan on changing the oil return tubes, those o rings may tighten and stop leaking, but once you start driving it they are sure to leak again. It is a fight to replace, but can be accomplished with little skill, and it is relatively affordable. Tons of posts on this site with tips.

I started to drive my '82 SC every day and the massive leaks from the return tubes stopped completely. I've read that the O-ring material that seals the oil tubes is very sensitive to contraction so maybe mine stopped because it's now driven most days. If Jeffery is driving his more, that could explain it as well.

Pete Zimmerman is pretty adamant that the tubes should be replaced with factory which means you can't do it right until you tear down the engine next time, if you believe Pete.

alan911 · 03-24-2007, 12:02 PM

Are you 100% positive you really put oil back in it ?

"Cause if a Porsche doesn't leak......well... you know the rest.

TerryH · TerryH's Garage

Quote:

Originally posted by alan911
Are you 100% positive you really put oil back in it ?

"Cause if a Porsche doesn't leak......well... you know the rest.

That quote related to older Harleys too.

I do have to brag that after repairing a few drips on the 81 SC I bought 4 years ago, the car never dropped any oil. Even after sitting for a week or two. So there are exceptions to every rule.

JeffreyNMemphis · 03-24-2007, 06:49 PM

3 days and 200 miles... no leaks yet. I keep going under it with a paper towel and wiping the engine case thinking maybe it will at least be seeping slowly, but for far nothing. If Norma Jean has a soul, then she has been loving all the new attention and affection. Maybe she was weeping oil from neglect and has found love again?

It was a beautiful sunny day here so I washed the car. My box of good stuff from Griots garage came Thursday when I was under the car. I told the Fedex man, "please tell that box is from Pelican Parts?" I can't wait to get my copy of Wayne's book and the Bently manual.

Anyway, I can't wait till tomorrow's daylight so I can start polishing.

Life is good...

Have you all seen this video? "Victory by design" Here is the link, I really enjoyed this:

http://video.google.com/videoplay?docid=-3611075207317469622&q=victory+porsche