It's easy to pull the crossover tube (over the top of the valve cover) to isolate cold-side oil leaks and blowby via PCV, but you won't have any boost during the test.

The turbo will be easier to evaluate when you have the head off to do the gasket and possibly replace the (cracked?) head. Bummer.

__________________
James Marriott
2003 Buick Regal
1983 300D (228k, frau Auto)
1996 Suburban K2500 (192k, 6.5 turbo diesel/4WD towmaster 10,000)
www.engineeringworks.biz
1987 300SDL junker 170k
1982 300SD junker, 265k