Identifying oil leaks on a cologne 2.8 V6

[limey222]

How do you identify the source of multiple small oil leaks on a Cologne 2.8 V-6.
There is a lot of oil covering the entire bottom of the engine and gear box probably from a few years of leaks. I've fixed the leaky rocker covers so I know its not them. How do I determine whether its the front (crankshaft) seal, the oil pan gasket or worst still the rear seal. The engine is a 1974 and it has the standard 4-speed manual transmission. The leaks aren't terrible, just annoying.
I would be most concerned if its the rear seal, costly followed by the pan gasket because of the work involved to fix it. I only drive the vehicle maybe 100 miles a week so I don't have a definitive idea of how much oil I'm losing but the dipstick level doesn't seem to dropping very much at all.

 

[rangerin]

If the front of the bottom is oily it could either be the front crank seal or the timing cover gaskets. If it's been leaking a while, everything downwind will be a mess even if the leak is small. Check your pressure sensor, it could be that too.

 

[adsm08]

That's when you just pull the engine and do a full reseal.

 

[limey222]

I've been suspicious of the pressure sensor for quite a while. There is a T-fitting that screws into the block. The pressure sensor (which I'm not using) is located in one side and a tube on the other that goes up to a mechanical oil pressure gage in my dash. I really can't get to it
unless the car is on a lift. My local garage mechanic connected the pressure tube and mentioned that the T seemed a bit loose but he couldn't screw it in any further due to an interference. Anyone know what size thread is in the block? I would just as sooner remove the whole assembly and just plug the hole.
I have an inline pressure gage under the hood on the line going to the oil cooler.

If the front of the bottom is oily it could either be the front crank seal or the timing cover gaskets. If it's been leaking a while, everything downwind will be a mess even if the leak is small. Check your pressure sensor, it could be that too.