My brother's EL wagon has an oil leak and according to the mechanic he took it to, it's leaking from the rear of the crank case. The mechanic stated that to fix it, the engine would have to be removed and flipped upside down to get at the problem.
Is that right? The engine has to be removed?

i take it there replacing the rear main seal? i would say u wouldnt have to remove the engine just remove the gear box/ tranny

That's a little non-specific. Saying it is from the rear of the crank case.

I presume he means the rear main seal. Or he could mean the sump gasket. In either case the problem can be fixed with the motor still in the car.

The only other thing I can think of is the head gasket. In which case the head can be removed with the engine remaining in the car.

If it is none of these things, I can't think of anything else.

I too was under the impression that removing the transmission would give plenty of access.

s**t easy to do, iv only done one but theres nothing to them

you are right, the rear main can be done by removing the transmission only. I had mine done along with the welsh plugs(2?) last year.

i have found that (even though there is quite a number of them that leak out the rear main) tightening the sump often cures the problem, especially on ELs. If it was an EF (or earlier) i would be more inclined to suspect a rear main. More to the point i would be going back to the mechanic and asking which of the 2 he thinks it is before having him cost you an arm and a leg to pull the motor out to do a job that can easily be dont with the motor in the car.