Hello, I have a 1987 740 Wagon Turbo FI and down near the oil trap there is a 3/8 plastic "T" with one 3/8 hose going up on top through the intake near the spring throttle "fishing reel" thingy and over the fuel rail and injectors. This hose down below has a white and black plastic disk in between the hose it looks like a "top" you could spin. It has a 3/8 fitting on either side and is about the size of a quarter. The only thing on it is marked "ATE" in script and a "3" "and arror to motor". It looks kind of "fram" brand or "duracraft" like.
It isn't a flame trap, is it? Because it can't be opened. Looks like a one way valve. You could look through it on one end and it has a sort of little wheeled screen and the other end is what looks like a ball. Do I need this? It doesn't look like a Volvo Part.