Hello, all.

I just installed new fuel lines and noticed a strange oil weeping from a hole in the block beside the water pump and above the timing belt cover. When I say hole, I mean a big hole, as in a threaded hole that looks as though something should be filling it! I always suspected the leak was coming from the timing belt cover, but I swear it's this hole. The fan mists the oil everywhere and makes a big mess.

Anyone know what this hole is for and how I might effectively plug it? Will that harm my engine in any way. It's so strange...

Here are a few pics I just took. I'm pointing at the hole:

http://i1033.photobucket.com/albums/a414/1966amazon/B20%20Oil%20Weep/b20_hole_2.jpg

http://i1033.photobucket.com/albums/a414/1966amazon/B20%20Oil%20Weep/b20_hole_3.jpg

Thanks in advance for any help,
Kirk

There shouldn't be oil anywhere near that hole, even if it was somehow drilled all the way through. I really don't see how that could be the source of the leak, but go ahead and put a bolt in it to see if that makes any difference. It's a 3/8-16 UNC thread.

That's a mounting boss for a power steering pump or A/C bracket. -- Dave

Thank you! Could/would oil leak from a mounting boss? It seems odd. Do you know the size of the thread, by chance?

I really appreciate your help.

-Kirk

I went out and looked at a block in my garage. It is indeed a mounting boss and if drilled
completely through it would come into the pushrod chamber.
I'd get a short 3/8"-16 UNC bolt and a flat washer and an O-ring that fits snugly around
the bolt. Screw the bolt through the flat washer and the O-ring into the hole and tighten snug
but not too tight. That should solve the problem. Your bolt probably should not be more
than about half an inch, all threads up to the head.
--
George Downs, Bartlesville, Heart of the USA!

George,

Thanks so much for your help. Just for safety sake I bought a few different size bolts at the hardware store...none fit.

The hole is 10.41mm in diameter or 13/32"

I figured 3/8 would be close, if not, a metric 10 bolt. Goose eggs. They didn't have 13/32" there. Seems like a crazy size. Any tips, guys?

-Kirk

It will NOT be metric. Will most likely be 3/8"-16UNC. Threads may be damaged.
--
George Downs, Bartlesville, Heart of the USA!

Let the engine set for a bit, clean the hole (Brakleen comes to mind) and then fill the hole with something like Permatex Ultra Black (oil resistant) gasket sealer. You might have to use a piece of tape to hold the sealer in place until it sets up.
--

Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

Plugging up the boss with gasket sealant is an idea, but another option would be to find a rubber plug to seal off the hole. This way, you can easily unplug it you ever want to make use of that hole for whatever reason...

-DS

It seems that you have something quite weird there.
If your measurements are of the minor diameter of the threaded hole and accurate then you are looking at the 'tap drill' size.
The nearest things that I see are a metric 12X1.75 at 10.2mm [.401"] or
A SAE 1/2-13 NC at .421" [ 10.7mm] The only other thing I can think of is the threads for a Helicoil or "Keensert" type insert that has since been removed or has fallen out on its own. I don't have my STI book in front of me so I am not sure of helicoil tap sizes for likely repairs.
Perhaps the hole was repaired in this way by a PO and drilled through - thus the leak?
You could always re-tap to the metric 12 (or 1/2"-13) worst case.

Good luck & Cheers!
OK