mystery oil leak, suspected head bolt.

[LevisJeanz]

Hey all, I have a decent size oil leak on the passenger side that seems to eminate from the cutout in between the pushrod tubes. I installed new pushrod tube seals before I put the motor in the car and recently added a Teflon based sealent to the rearmost tubes where I thought it was leaking from originally. Could it be the headbolt in the cutout? Its number 3 in the attached picture.

When the engine is running the oil spatters out from that area. The oil is extremely dark and the oil I saw in the pushrod tubes looked brand newso I doubt its coming from there. Where could this be coming from?

[Dave at Pelican Parts]

There is a sealing washer or ring (forget which) under the bolt head; this can be replaced.

The stud that holds the oil strainer and sump plate onto the bottom of the engine is held by this bolt; the top of the stud has a ring that goes around the bolt. If you overtighten the oil strainer retaining nut, it can pull the stud down bending this bolt and cracking the crankcase. This is Very Bad News Indeed, and not something that can easily be fixed. (And that's one reason the torque spec on that nut is NINE ft-lbs, and should not be guessed at.)

Hopefully that isn't your problem.

The fact that the oil that comes out is much darker than what appears to be in the engine may mean that it is leaking down from somewhere above there. The most likely thing I can think of (or at least it is with me!) is spillage from filling the oil, or (if you have a 70-72) from the oil-bath air cleaner.

--DD

[LevisJeanz]

It's a 75 2.0 is there anything I should be aware of before removing this head bolt? Do I need to take the strainer basket out first?

The car had only been driven around the neighborhood once or twice. The Po said that the lower end of the motor had been rebuilt and I assembled the rest. Could any of these be clues as to why the oil is darker?

Seeing the dark oil makes me nervous should I be worried?

[Dave at Pelican Parts]

If the oil in the motor is fresh, and the oil you're seeing is dark, the oil probably isn't coming from inside the motor. Or at least it is picking up a bunch of dirt after it leaks out of the motor.

The #3 bolt isn't a head bolt. It is one of the regular case bolts. It threads from one half of the case into the other half of the case. It wouldn't be the worst idea to remove the strainer before you remove the bolt, because that would allow you to make fine adjustments to the hanging stud if you can't get the bolt back through it when you re-assemble.

--DD