Engine Guru's... Oil Leak!

[TurboRuf]

Fixed my fuel line problem… on to the next.

After starting the engine today I noticed a nice little puddle of oil under my left heat exchange. I tried tracing the steady drip to its origin without success. It’s coming from the area of the dizzy but it’s not leaking from the dizzy’s shaft seal (see the brown area, leaking oil, in the attached image). It appears to be coming from the area above the dizzy, closer to the oil line. This would seam like the obvious culprit but it doesn’t appear to be the leak. I’ve examined the oil line closely and it looks fine.

Since I can’t run the car with the distributor out to actually see the leak, it makes it very difficult to isolate.

My questions are the following:

What goes in the question mark area (see image)? It’s currently plugged with a bolt/washer, not sure if it attaches to something or just seals. Could this be leaking? Can I remove it to check or does it have a function?

What else in this area could be leaking?

Thanks

[Jim Sims]

I believe the question mark on your figure is directed at the nut side of one of the case through bolts. This bolt is one of the structural elements of the engine; it resists crankshaft loads. It is an "acorn style nut" (Item 28 in the figure is one of these nuts) so it looks somewhat like a bolt head. Underneath the nut should be a beveled washer (item 27) and under the the bevel of the washer there should be a rubber o-ring (item 26). The washer and o-ring are required because the holes for these through bolts are also oil galleys and hence must be sealed. If there is oil coming from the nut it is either loose or the o-ring has failed. I'm not sure but to get to the head of the bolt on the other side (passenger side) to attempt to re-tighten you may have to remove some of the air conditioner system brackets (if equipped with A/C) and the sheet metal/plastic hot air ducting at the rear of the engine on the passenger side. Check the passenger side of the engine. If the bolt is tight then the o-ring is likely bad; I don't know what the risk is of loosening this nut and replacing the o-ring and then re-installing and re-tightening to the correct torque. There may be a risk of starting a leak in the sealant around the case seam or nose bearing if this bolt tension is relieved. Perhaps someone with more experience will comment. Cheers, Jim

[Wayne 962]

Here is a better pic:



This is an engine through-bolt, and you can replace the o-ring behind it. Also make sure that you coat both o-rings (there is one on each side) with a little bit of black silicone, after you clean the area up.

This should hopefully solve your problem...

-Wayne

[TurboRuf]

Wayne,

Wow, that helps clear things up. A good photo makes a world of difference.

I'll let you know if that cures the problem. I appreciate all the help.

[TurboRuf]

Jim... thank you too! Wayne's big picture caused me to overlook your post. Very helpful.

[ChrisBennet]

With all due respect to Wayne, I avoid silicone/RTV gasket stuff like the plague. That O-ring is in contact with the engine oil and the thought of little black silicone boogers making their way to my piston squirters or spray bars would keep me from sleeping well. A light coat of oil will allow those O-rings to seat well without getting pinched.
-Chris

[Jim Sims]

I was taught the below technique for these through bolt o-rings. It is a bit unorthodox but originates in a well respected Porsche engine machine shop and it produces long term leak free through bolts. The sealing area and bolt/nut/washers are thoroughly degreased and then the o-ring and washer (on the side facing the case) are "buttered up" with Loctite 574 (the orange engine case sealant) and installed. All the through bolts are tensioned within 15 minutes before the Loctite 574 cures. Cheers, Jim

[Wayne 962]

I like to use black silicone. The 574 is designed only to cure metal to metal, and only in the absence of air. The manufacturer only recommends it's use in tight fitting gaps, and not for use on plastic.

http://www.loctite.com/datasheets/tds/Product_574.pdf

Again, I recommend black RTV from Permatex. It seals great, and after you trim the excess, you won't even know it's there!

-Wayne

[Superman]

I also avoid silicone RTV, but Wayne may have meant silicon grease. I put Dow Corning 111 silicon grease on those tiny o-ring buggers. I put it on ALL o-rings, in fact, and it keeps them from leaking.