I'm new to volvo, and have been learning alot how to repair and diagnos problems for the future on my 1990 740 GL regina 291,565 mile car, I acquired it with 289,000 miles - it had been maintained fairly well. I recently had distributor cap, rotor, spark plugs, fuel filter replaced. Also, I just replaced the flame trap mostly clogged up and took off and cleaned the TB.
Question 1:
I was wondering b/c ipdusa.com sells PCV Oil Separator Boxis that something that you have to change ever to keep you car going 500,000+ miles

Qustion 2:
the main hose atop the flame trap filter piece is rather short and winds through lot of other hoses, would there be anything potentially wrong with making it longer and routing it over all the pipes for easier cleaning access.

Question 3:
Is there any other items that are common wear that should be checked replaced often?

-Also is there any place I can find diagrams or pictures that explain which lines and hoses are what under my hood. Some looking like they may need replacement soon, but are very thin, long, and somewhat fragile looking.

Thanks in advance

 

The oil separator box is a non-wear item. But sometimes they crack from old age. And sometimes they get so clogged up that it's just easier to replace than try and clean out the old one.

A longer, more convenient hose routing, would be OK.

 

Thanks for the info

 

there should be a vacuum hose routing sticker somewhere in your engine compartment, usually on the flat near the hood lock.

 

how do you remove the oil separator box? where are the bolts that hold it on?