As Gerald says, there is none but a flame trap that is plugged up will run crankcase pressure up and blow your rear main oil seal, an expensive repair. The photos on Bay 13 should help you find it although it is hidden pretty well. It's in the large bellows like air intake hose running from the air cleaner to the throttle body on the back side and looks like a tiny spagetti strainer. Remove this large hose and you can see it with a small mirror. To remove it, you need to turn it about an 1/8 turn clockwise (I think) as you face the engine and it will pop out in it's holder but attached to two vacuum lines. If it is really cruddy, it can be a royal pain to remove from it's holder. Some guys drill a hole in it and start a screw that can be grabbed with pliers to pull it out. Have a new one on hand ($1-2. cheapest part on a Volvo). If it isn't plugged, FI cleaner shot thru it will clean it up but at 60K I'd replace it

bl