Fixing Major SC oil leak

emarsh · 04-15-2004, 04:18 PM

Hi,

When I bought my '79 SC it leaked oil, which only got worse (much worse) as time went by. This winter I pulled the engine out so as to go through the transmission and while I'm fixing the tranny I want to fix the oil leak too.

I'm not exactly sure where it is coming from but the top/front of the motor is a greasy mess so I suspect that the source is somewhere around there.

I bought a copy of 101 mods but don't know where I put it. Thought I'd ask here exactly what parts I should be ordering, and replacing, while I'm ordering the tranny parts.

Can anyone give me a run-down?

Thanks,

Eric

keithdog72 · 04-15-2004, 04:37 PM

A common leak in that area is the breather cover gasket and hose. Also the thermostat o-ring. Not a bad idea to replace breather hose while you are in there because it is a bi-atch with the engine in and it's fairly inexpensive.

rlane · 04-15-2004, 04:42 PM

Mine leaks from the on engine oil cooler seal and also from the oil pressure switch. Do a search, there are multiple threads on curing leaks, also check the tech articles, I beeive there is one on fixing these as well. Also buy Waynes book on engine repair, if I recall he has a section on parts to replace while you have the engine dropped.

jrb964 · 04-15-2004, 05:14 PM

All good recommendations. Another area is the oil cooler. Remove the cooler, secured by four bolts, replace the three gaskets, take the cooler to a shop and have them flush it out. I did my SC a year ago, and it barely get the needle in the safe zone.

GB83SC · 04-15-2004, 05:47 PM

Replace the rear main seal while the motor is out, the one behind the flywheel.

Don't forget to look at the intake runner hoses if they are puffy replace them.

All of the above are a must also.

mikebrasket · 04-16-2004, 01:42 PM

The crank case seal on mine needed to be replaced as soon as I got it.... luckily I also needed a new clutch so I had to have the engine out anyway.

Mike
-----------
'79 911SC Targa

Groesbeck Hurricane · 04-17-2004, 06:44 PM

Eric,

Where in Central Texas are you?

While the engine is out I'd replace gaskets, o-rings, and the oil sender.

ChrisBennet · ChrisBennet's Garage

I don't get out much but I've never seen a leaking oil cooler seal. I've seen oil leak down from above and run down by the oil cooler and I've seen the case leak behind there but never a leaking oil cooler seal.

The oil pressure switch and the thermostat O-ring are favorite leak points.
-Chris

john walker's workshop · 04-17-2004, 07:22 PM

don't forget the red oil light switch. they can leak like a sieve. seive? have a shop pressure test the cooler while it's off. most porsche shops have the tool.

sammyg2 · 04-18-2004, 05:59 AM

When I had my engine out I replaced the idiot light oil pressure sender, the crankcase vent gasket and hose, the oil cooler seals (they wuz cheeep) installed pure silicone valve cover gaskets, replaced the intake runner sleeves, and upgraded to turbo cam oil restrictors.

emarsh · 04-18-2004, 06:35 AM

Thanks gang, I think I have enough for a shopping list.

Groesbeck, I'm in Cedar Park, just a bit north of Austin.

Danskman · 04-18-2004, 08:48 AM

All of the above, as mentioned. Don't overlook the oil return tubes. I almost put the engine back in without replacing them, and it turned out that they were one of my biggest culprits. (Thanks, JW!)

Groesbeck Hurricane · 04-18-2004, 04:21 PM

Eric,

Looks like you have been given some good advice. I hope the motor is still out, it is easier to do while out of the vehicle. I would believe the leak is coming from the top of the motor and just appears to be around the internal cooler.

Cedar Park? I just met a couple from there today. Small world, but you are hours away from me. I hope some Austin folks pipe in. They might be able to swing by and help? Best of luck,

emarsh · 04-18-2004, 04:58 PM

Quote:

Originally posted by Groesbeck Hurricane
Eric,

Looks like you have been given some good advice. I hope the motor is still out, it is easier to do while out of the vehicle. I would believe the leak is coming from the top of the motor and just appears to be around the internal cooler.

Cedar Park? I just met a couple from there today. Small world, but you are hours away from me. I hope some Austin folks pipe in. They might be able to swing by and help? Best of luck,

Thanks. Yes the engine is still out. Fixing the leak will hopefully be trivial in comparison to the real reason everything came out, to rebuild the transmission. I think that you are correct about it coming from the top, however the car also leaked badly when it was just sitting.

It will probably cost me $1000 by the time that I have the car running again, but its worth it. One thing about the Porsche is that there is a certain magic to it - it has a way of making a person happy just driving it so its well worth spending a little on now and then.

Groesbeck Hurricane · 04-18-2004, 05:06 PM

Interesting, where did the oil pool when it just sat? Under the back of the car? Under the fan? Or just around the middle? It could be a very easy seal to fix.

You might look at adjusting your valves while the engine is out. Replace the gasket with a re-usable silicone bead gasket.

emarsh · 04-18-2004, 05:15 PM

Quote:

Originally posted by Groesbeck Hurricane
Interesting, where did the oil pool when it just sat? Under the back of the car? Under the fan? Or just around the middle? It could be a very easy seal to fix.

You might look at adjusting your valves while the engine is out. Replace the gasket with a re-usable silicone bead gasket.

It was pooling somewhere more to the right side. I ran the valves about 3k miles ago so they should be OK for a while.

I'm going to take care of the stuff on top of the motor as well as the cooler and flywheel seals for sure. If I still have problems then they ought to be accessible from the bottom.

Groesbeck Hurricane · 04-18-2004, 05:29 PM

Is it possible that either this oil was left over from what leaked at the top and then it ran down? This was an issue I had.

The next thing is could the valve covers have been overtorqued? Mine leaked the first time I did them because I overtightened them. Took them off, cleaned everything, and used the proper torque wrench.

emarsh · 04-18-2004, 05:34 PM

Quote:

Originally posted by Groesbeck Hurricane
Is it possible that either this oil was left over from what leaked at the top and then it ran down? This was an issue I had.

The next thing is could the valve covers have been overtorqued? Mine leaked the first time I did them because I overtightened them. Took them off, cleaned everything, and used the proper torque wrench.

The leak started several thousand miles after I ran the valves. I don't think it was running down from somewhere because I parked the car for a while before ordering parts and the puddle kept growing.

Once the engine has been degreased if I still have a leak it should be much easier to find.