What part to fix this oil leak

rlw · 03:01 PM

I have an oil leak between the crankcase and oil cooler (I think that is what it is called) (or the oil line from the cooler). I have searched but I am not sure what seal or seals (part #'s) I need to fix this. Also, any advice about how to fix it? Does the oil cooler need to be removed or is it just a seal between the line and the crankcase?

Thanks!
RW
1989 911 Carrera Cabriolet

The oil is coming from between the bolts in the center of the picture. It's shiny from the fresh oil that slowly leaks though it does not leave a drop of oil on that garage floor.

p911dad · p911dad's Garage

That appears to be a nuisance leak, and probably normal for the age of the Porsche. It could actually be coming from above, on top, where there are several sources of oil leaks, well documented on this site. I would just keep an eye on it and live with it. Wipe it down well and look at after each use of the car, maybe it is from the oil cooler seals(all these parts are available from our host). Place a clean section of cardboard on the garage floor under the engine and if there is any increase in flow, it will be recorded there for all to see. If you are new to 911's, get a good service manual(like Bentley) and study it, it can save you big $$ over time.
By the way, it would help the board to know what model and year you have and maybe post a few photos as well.

rlw · 10-18-2009, 03:06 PM

I have cleaned up the area of fresh oil, went on a spirited drive, and the whole area was covered in fresh oil so I think the leak has some volume to it. I have tried to see if there were any leaks above or around and this is the only place I can find. I will start leaving some cardboard on the ground. I have a Bentley manual along with 101 projects. I have looked and searched but not come up with this exact area. That being said I probably skipped an entire chapter on this exact problem

RW

James Brown · James Brown's Garage

took me awile but the picture is from the bottom looking up. So the leak could be higher up the oil cooler. or from the top like the idiot light switch or the breather/oil thermostat.
can you look behind the engine at those items? A 3.2 is easer to see back there than a 3.0.
If it dry there, then the oil cooler should be pulled and checked for leaks. then all new seals and it SHOULD be fixed for a few miles. Or live with it (cardboard is cheap).

uwanna · 10-18-2009, 03:46 PM

Sounds like a slow leak in the oil cooler! I have the same problem, oil has a slow drip after the encine is warmed up and driven for a bit. The oil in the return pipe is not under pressure, and the return pipe to crankcase margin rarely leaks.
You probably have a pinhole leak in the cooler, which only shows up when the engine is warmed up, and the internal thermostat has opened. the oil then only leaks when under pressure and slowly leaks and runs down to the bottom of the cooler.
the reason you d/on't see oil on the floor, is the oil drips onto the exhaust/heat exchanger and burns off. at least that's what mine does.
I would start looking for a good used cooler on the buy and sell forum, as repairing one is not worth the trouble or expense! I have seen several of them there of late.
Replacing the cooler can be done with the engine in place! Just do a thread search, and you find help.
Have a replacement cooler for mine, and plan on doing the job soon. I'll let you know how it goes. Good luck!

James Brown · James Brown's Garage

hey uwanna, do you have an oil cooler in the 3.6 or is there a filter in it's place?

uwanna · 10-18-2009, 04:11 PM

My 3.6 has an oil cooler. I did the 3.6 upgrade back in '92, when very few folks had done it. When noticing there was no engine mounted cooler, I was bound and determined to retrofit one! The reason a 3.6 has no cooler, is because of that pesky power steering pump. Once I got the damn thing out of there,and the end of the cam cut off and blocked off with a plate, I tackled the oil cooler.
I guess I was too naive to think it could't be done!
I have a thread on the topic here:3.6 transplant oil cooler question

since that thread, I remembered a couple of things I hadn't included in the procedure. But anyone interested in this upgrade can PM me or reply to that thread

James Brown · James Brown's Garage

wow thats just "cool" I'm thinking that a 3.6 upgrade is the cheapest way to make the most power in my sc. I would like to use the PMO ITB's on that 3.6. Anyway, the cooler mod looks great!
RLW, time to get that socket set used!

john walker's workshop · 10-18-2009, 04:52 PM

most of the leaks in that area are from the top of the bellhousing area. the oil light switch, the thermostat o-ring or the breather hose. check that area with a mirror and flashlight. you can get a better view by removing the air cleaner and airflow meter. takes just a few minutes.

uwanna · 10-18-2009, 05:06 PM

James Brown,
Do a 3.6 upgrade, you'll never regret it! Turns an SC into a "rocket".
I read all about the the fancy upgrades folks are doing to 2.7-3.2 motors, and spending big bucks to do it to boot! In most cases they don't even approach the HP and torque of a stock 3.6. Plus for the cost of a quality rebuild of an earlier motor, you can find a good 3.6, and after your retrofit you can sell the left over motor to mitigate the cost!
As far as carbs, I think I'd keep the Bosch Motronic system. Vitually trouble free and bullet proof, and besides, how much "go power" do you need! Mine will run run with 993s and 996s, with nothing but a "Cup chip" added.

uwanna · 10-18-2009, 05:17 PM

RW,
John Walkers suggestions are right on, do that stuff first. I did all those things before determining I indeed had a leaking cooler. Got the air cleaner box out of the way so I could get a good look at the upper rear area of the case where the oil switch, thermostat, etc, are located. Cleaned everything up spotless with a pressure cleaner on low pressure to make sure I had no leaks from back there.

rlw · 10-18-2009, 05:27 PM

I jacked the car up again and got my new craftsman creeper a creepin and shop light a shinin. I searched high and low around that area and could not find an obvious source, other than fresh oil at that spot in the picture. I have to work late the next couple of days but Wed I should have time to do what you said John and I will report back.
Thanks all!
RW

NOLAsc · NOLAsc's Garage

I know... This is 14 months later, but did you find your leak and your cure RW?