The Airwolf will work on your 0300-D with wet vac pump.
You need two M-20's to do the same job - one for oil & one for wet vac pump.
Have you cecked out the photographs pf the M-20 split in half to show what
is inside it?
You'll find them on the Airwolf website

HTH

Tony
C-GICE

In article .com,
" wrote:

I am considering installing an air-oil separator in my 172H (Cont
O-300d). I have spoken with Airwolf who say theirs will work well and
is ALMOST STC'd but they "will provide the required paperwork to make
it legal until the STC comes thru" (whatever that means).
I also spoke with Aircraft Spruce who say the M-20 is the one for my
plane and it is already approved.
Airwolf is $495 M-20 is $360

Any suggestions/PIREPS/considerations/anecdotes appreciated.