Another Leaky Engine!!!

So I take my car in for a check up and my mechanic says that it looks like I undid a oil return tube, sprayed the underside of my car, then put the tube back on!!!

So my task is to clean the underside of the car to locate the leak....ARGGGG

But I have been thinking, because of my inexperience I used Valvoline "racing" 50W oil in my engine, I know (now) that the suggested weight is 20-50...is this maybe part of the problem? I know sythetics tend to cause leaks...but can 50 instead of 20-50 be a problem?

Any suggestions on tracking them down, I am going to go to a self car wash facility, spray the crap out of the underside...I am planning to jack the car up in those booth (probably get wierd stares from the cars passing in the street) take off the wheels, spray there (the oil tank reserv. seems to have a THICK layer of gunk!!!) come back home, jack it up again, change the oil (to 20-50) scrub the stubborn areas, till spotless, drive around for a bit, then jack it up again, and lay under the car, reading a book till I feel hot oil drip on me!!!

hmmm...fun weekend....maybe I should use glazing compund on the car while I wait!!!

Anyways...I am starting to fully absorb the "joys" of Porsche ownership!!

Another note...guru Warren has suggested SAE90 instead of 80-90 Swepco for 915...wonder if anyone has had expereince with this...



[This message has been edited by 82SC (edited 12-04-2000).]

Straight 50 weight is not the problem. That's a trick used-car guys use to keep an engine from leaking. It's thicker.

Good luck on the leak hunt. Don't let the thing fall on you.

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Jack Olsen
1973 911 T (3.6) sunroof coupe

You do have jack stands of the 3-Ton variety, right? Under the torsion bar tubes is a good, secure location for the rear ... and also the same point the dealership lifts use! A roll of paper towels and a couple of cans of brake cleaner/degreaser might be put to good use on the oily mess, along with a couple of bristle brushes. If your engine doesn't already have them, now would be a good time to get and install a set of collapsible oil-return tubes.

I'm sure you will find SAE 90 gear oil listed as the only lubricant (like the brand new Bentley manual) for your transaxle in your owner's manual, and multi-weight gear oils were available when it was written!

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Warren Hall
1973 911S Targa

82SC,

According to Bruce Anderson, SAE50 engine oil is to heavy for 911's. The October, 2000 issue of Panorama listed all the oils (and weights) approved by Porsche AG. I use Mobil 1 in both my 911's (1977 and 1984). I use 10W30 in the winter and 15W50 during track season (i.e. Driver's Ed events).

I agree with Warren in terms of transmission oils; I use Swepco 90 weight in both my cars and it works great with the 915 transmissions. Swepco 80W90 is not a bad choice, but IMHO 90 weight is better, especially for track use.

Regards, Bruce

50 wt oil is not the problem, but 20/50 should be used instead.

I get stares when I lift a car in the wash booth, but I like getting "you're crazy" looks. Be sure to dress the part.

And either leave the engine running or cover the distributor with a plastic bag and twist ties or rubber bands. If this gets wet, you'll have trouble starting.

Spray like a madman. Spray spray spray. Five extra minutes in the booth will save you an hour under the car.

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'83 SC

There isn't a problem spraying a hot engine with cold water? I've always been worried about doing that.

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Bill Krause
'79 911SC Euro

When I cleaned mine, I was told to leave it running and it wouldn't be a problem. If you turn it off you'll want to let it cool completely. I only washed the underside of mine. I don't see how you can wash the top around the MFI pump and breather cover with the air filter shroud in place and the engine running. If you remove the air shroud I would think you'll have to cover the stacks w/ plastic bags as well as the distributor, coil, and relay/fuse/cdi unit.

I assume you also don't want to spray anything like Gunk on a hot engine as it is combustible, which would be another good reason for turning it off and letting it cool.

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Greg
72 911S

Excuse my ignorance but what are collapsable oil return tubes?

What are the advantages?

Where are they located?

How much to change?

thanks

MJ

Diving in before anyone else here...

We're getting off topic (again!) but the oil return tubes are the... well, tubes that connect the camshaft housings to the main engine case.

There are four of these tubes, 2 on each side of the engine.

Because the engine is air-cooled, it expands and contracts with temprature quite a bit. The oil return tubes have a thick "O ring" type gasket at each end that is designed to cope with the expansion/contraction cycles.
Believe it or not, the tubes actually move backwards and forwards a bit, as the distance between the camshaft housing and the engine case varies with temprature. (You'll learn that on some engines, this has undesirable effects on the head studs as well, but that's for another topic!).

Alas, nothing lasts for ever, and as the car ages, these gaskets get brittle and leaky. When one fails, it can often dump spectacular amounts of oil all over the lower part of the engine... Provided you are aware of the problem, you can carry on like this for quite a while, since the oil that is being dumped is on its way back to the engine case to be pumped back into the oil tank - the oil has done its work before it ends up sticky and forlorn on the outside of the engine. Obviously you'll have to keep a sharp eye on the oil level, and keep topping up at regular intervals.

The gaskets and oil return tubes need to fix the problem are quite inexpensive. BUT fitting them means you have to drop the engine and remove the camshaft housings. This is a big expensive job.

So... some bright spark invented the "collapsable" or "telescopic" style oil return pipe. Unlike the old style pipes, these can be installed from underneath the car without having to remove the engine, and (if properly installed) seem to be just as durable as the original design.

You can get these pipes here at Pelican, but first things first; Clean the underside of the engine and find out where the oil is coming from - The leak may come from somewhere else completely.

Caretake,

- roGER

Thanks Roger

What you describe sounds like my problem
my engine runs cool, but I am constantly having to top off the oil...1`qt every 400 or so...when I changed the oil there was a bit of leakage along the Pass side of the oil cooler? Is that the dreaded oil thermostat O-ring???

Also I do NOT get a puddle of oil under my car...at the rate I am losing it I would think I would find evidence, but instead I think it is getting smeared on the underside...and drying and caking there...I also get some burning in the mornings, but that is normal (smoke out the tail pipe that is)

But I will have to ask one more request that someone give me an outline of this job. changing the oil return tubes...

I will track down leaks before I start taking things apart...so where am I looking for oil if it is in fact the oil return tubes???

thanks

MJ

[This message has been edited by 82SC (edited 12-04-2000).]

To 82SC: The first thing you should do is read the Pelican Parts Tech Articles.You will find alot of info on doing the tasks you have been asking about including how to change the oil return tubes.

Kurt V
72 911E

I (and you also I suspect) have classic examples of what Warren calls a "dynamic" oil leak.

Oil dribbles down the back (toward the front of the car) of the Oil Cooler. It gets all over the starter and also dribbles aroudn and keeps pretty much the whole underside of my engine wet with oil. It is my Oil Cooler Thermostat o-ring.

You see oil has to be pushed past this old o-ring in order to get out of the motor. The o-ring sits near the top of the engine case, and gravity will not encourage the oil to go up and out past the o-ring. Engine oil pressure is what does this.

So, our leaks only occur while the engine is on. We are leaving substantial quantities of oil on the roads we drive, one drop at a time. when we pull into our garages and shut the engine off, the leak stops until the next morning when oil pressure resumes.

I've decided that on my engine, with all the CIS stuff in the way, the o-ring replacement procedure will involve engine removal.. Wish I had known about this $1.40 part least May when the engine was on the floor of my garage.

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'83 SC

I feel for ya Superman. This makes a good point for a decent manual that has cross reference capabilities. Whenever I have something apart I am always wondering what else I should be doing.

Well, I didn't see it as its apparently not visible even with the engine out. I tried to replace every cheap thing that made sense.

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'83 SC