Air filter oil tube: 1982 vs 1985 300TDT

[300TD1982]

Hi, my car is a 1982 w123 body with a 1985 engine. w123 300TDT OM617.952

My question is: Does the 1985 engine have an oil return tube from the air filter to the engine? Someone said that it does not.

I took off the air filter today for the first time to try to find the exhaust leak. It turns out that there is no oil tube, just an open hole in the bottom of the filter housing. My blowby was puffing out the bottom!

Is it true that the 1985's don't have an oil return from the air filter to the engine? If they don't, where does the separated oil go?

Many thanks!