2012 Peterbilt 386

[Rawze]

(10-14-2018 )Aleeex Wrote:  ...

Next is an oil pan gasket, and timing gear case needs to be resealed.
...

Those are typical signs that the engine has a lot of blo-by and/or someone neglected replacing the crank case filter often enough. I would do a blo-by test on it of sorts and ensure that is not your problems before pouring money into fixing those leaks, as it will not do any good.

Also, one of the biggest causes of leaks behind the front gear cover, especially if it is on the drivers side, leaking down behind the air compressor, is almost always a sign of completely worn down injector cam bearings. - I.E.> it is a sign that the head is on its last bits of life and in need of replacing if the leak is where the gear cover meets the block. Usually it is not the gear cover itself, but rather the retaining plate for the injector (or valve if it is the other side) cam leaking instead.

Not saying that is your problems but what you described + pics of an old engine usually = what I just mentioned. Plan on a new head + an inframe if what I mentioned turns out to be the case is all I am saying. When buying used equipment, always plan for the worst. Leaks in those areas behind the gear cover could very well be the reason it was sold in the first place, someone knowing the engine was done for.