Oil leaks after rebuild, Dropping motor to track down oil leaks Options

[Wew]

Hi all,

Engine rebuild has not gone as smooth as I had hoped.

I am dropping the engine again to figure out the source of my leaks.

I have drips coming from a couple of the tube on the passenger side under the oil cooler.

Tough to tell if it's the cooler or the tubes.

Cylinder 3 is giving me the most concern.

It almost looks like one of the four cylinder studs is leaking oil.

I can't tell exactly as it could be the actual mating surface of the cylinder and the block.

Anyway I am dropping the motor to track these down.

Has anyone else come across oil leaking out of a stud or is this just the cylinder and engine mating surface leaking?

If it is how have any of you remedied this?

Is there a bullet proof sealant that others have used to stop this?

Attached is an image I borrowed online that shows the location of where I see oil coming from.

Thanks for sharing as always.

[Superhawk996]

Been there, done that with leaking oil pressure switch bore.

You're not going to like my solution. Not saying it's the only one but it made sense for me since I'm dealing with a bare case.

Considered the other solutions (threaded inserts, taking hole out to 1/4 NPT, etc.) Might give you some other ideas.

See post #182

http://www.914world.com/bbs2/index.php?sho...5209&st=181

Note: 1/8 NPT and M10x1.0 tapered pipe thread are almost exactly the same thread form both by OD and thread pitch. I've done the comparison on some other thread elsehwere on how little the thead pitch differs. For practial purposes they are interchangeable if you end up in a bind trying to select thread inserts, adapters, etc.

As indicated by Mark above, make absolutely sure that is where it is leaking from before you go nuclear on it.

I'd start with your 1st suggestion. See if you can get an ISO tapered pipe thread tap in M10 x 1.0 and tap it deeper to get more engaged threads. Failing that you can try the sealing washer if you can tap deep enough to get the flat base of the sensor to seal on the washer AND have enough threads to establish the needed clamp load.

Here is an excerpt on difference between ISO taper and ISO straight threads:

There are two variations of ISO pipe threads. Parallel threads (also called straight threads) and taper threads. Taper threads have a 1:16 taper and the same reamers can be used as for NPT threads. Reamers are not strictly necessary but in the larger sizes they enable a better thread to be produced. ISO pipe threads, when specified, are assumed to be parallel unless a taper thread is called out. Taper threads seal on the threads themselves. Parallel threads, if a leaktight fluid seal is required, seal with a gasket, washer, or O-ring against the female seat. Since there is only one thread pitch, the thread pitch is usually not specified and they are called out only by nominal size as noted below.

From:
https://www.womackmachine.com/engineering-t...t-thread-sizes/