Buick oil leaks

[VPRob]

Hi Folks. A couple of months ago I did the engine mounts on my VP V6 and took the time to give things a good wipe off underneath. It hasn't taken too long for the telltale drips of oil to start re-appearing under the car. A mech I had been using also flagged oil leaks as a problem for rego inspection so it's been on my radar for a while.
Having a good look from underneath with the car up on ramps I can see signs of oil leaks from higher up on the block at the back of the motor as well as some from the areas behind the alternator and above the water pump.
What are the most common culprits? Inlet manifold gasket? History unknown on this motor. Rocker cover gaskets? Replaced when I installed the motor, which was a 2nd hand buy with about 200,000 kms on it, 6 or 7 years ago. Timing gear cover? History unknown also.
Not keen on doing a de-grease on my property but could pay for a detailer to do it so as to get a better view of the leak sites.
Any tips or experiences to share? Thanks everyone.

 

[losh1971]

Common leaks I addressed on mine, rear main, rocker covers, sump, and front crank seal. The timing cover rarely leak but the crank seal often do. The heads are probably leaking oil but they rarely get bad enough that it makes it necessary to fix the problem. My manifold wasn't leaking oil but the gaskets were allowing coolant and oil to mix. I'd start with rocker covers and then degrease. Sump can be done in the car but it's easier if you remove the engine and do the rear main at the same time.

 

[VPRob]

Thanks Losh. Sump gasket I did when I put the motor in because the original sump had a stripped drain plug so hopefully that's not too bad. Did the rear main too although it's had a slight leak for a few years now. What's involved in the front crank?

 

[losh1971]

Balancer off, seal off by putting a tek screw on the inside edge and pull him out, Bang a new one in.

 

[losh1971]

I paid a mech 50 bucks to replace mine with a seal I provided. It's easy to do but the puller is like a 150 bucks and if yours' is like mine you need the right tool or risk damaging the balancer. I replaced it once myself with a three jaw but the balancer was fucked anyway, so it didn't matter.