Does it look like I need to replace the PCV system?

[Sheggies]

Hey so I recently bought a N/A 1996 850 wagon with a 5-speed and while it's been well maintained it does need a few things here and there (I posted another thread about it). Either way, one thing that everybody says to keep a close eye on is the PCV system. Now, I've done all the tests and the weird thing is I'm getting mixed signals on whether to replace it or not. So, I figured I'd come on here and ask you guys.

On the one hand, the vacuum tube next to the fuel rail is pretty hard but there also isn't too much oil leakage on the top of my engine (at least not much recent, from what I can tell). Whenever I take the oil dipstick out after a drive I never notice any smoke coming out or any pressure or anything outside of normal. And finally, when I did the glove test a couple days ago I noticed the glove filled a little bit but not much (it didn't seem to be suctioning at all though). I've included pictures below of both the glove test and the top of my engine to further show you what I mean.





Any help is appreciated.

[FireFox31]

I recommend cleaning the PCV if you have time and intend to keep the car for a while. Like you, I just got a car with 200k mi, so I cleaned the PCV and replaced its hoses as a preventative, even though my glove test passed. Your glove test is failing, though barely. The most clear visual indication of a bad PCV is oil leaking from the oil trap under the intake manifold. From under the car, check the front of the engine for oil leaking and staining.

This 1999 V70 PCV write-up contains good information about a clogged oil trap drain port and how to test and cleaning the blockage. All the assembly instructions surely differ from your 850, but the method of snaking out the caked on crud with a firm, small diameter tube could help you. When I did it, I cut the end of the tube on an angle so it could make the sharp turn inside the engine block.

Check the maintenance records or ask the previous owners if they serviced the PCV, which they may have if they took care of it. The job requires a lot of inexpensive hoses, clamps, and gaskets (and the ~$50 oil trap which you can clean by adding some degreaser or carb cleaner and shaking it around). With everything apart, you might find that your dipstick o-ring shrunk and is letting oil out, or that the intake manifold is full of crud and should be professionally cleaned. And it's a good excuse to clean the throttle body. All of these things are steps to rehabilitate the car to a healthy baseline for years of trouble free use.

[manovlov]

In general, some oil on the top of the engine is the sign that the cap seal needs to be replace.

[FireFox31]

In general, some oil on the top of the engine is the sign that the cap seal needs to be replace.

I have read that oil on the top of the engine pushes out of the cap due to clogged PCV letting pressure build up. My engine top was covered in oil, but the PCV was in great condition. Worth double checking this info.

[Sheggies]

I recommend cleaning the PCV if you have time and intend to keep the car for a while. Like you, I just got a car with 200k mi, so I cleaned the PCV and replaced its hoses as a preventative, even though my glove test passed. Your glove test is failing, though barely. The most clear visual indication of a bad PCV is oil leaking from the oil trap under the intake manifold. From under the car, check the front of the engine for oil leaking and staining.

This 1999 V70 PCV write-up contains good information about a clogged oil trap drain port and how to test and cleaning the blockage. All the assembly instructions surely differ from your 850, but the method of snaking out the caked on crud with a firm, small diameter tube could help you. When I did it, I cut the end of the tube on an angle so it could make the sharp turn inside the engine block.

Check the maintenance records or ask the previous owners if they serviced the PCV, which they may have if they took care of it. The job requires a lot of inexpensive hoses, clamps, and gaskets (and the ~$50 oil trap which you can clean by adding some degreaser or carb cleaner and shaking it around). With everything apart, you might find that your dipstick o-ring shrunk and is letting oil out, or that the intake manifold is full of crud and should be professionally cleaned. And it's a good excuse to clean the throttle body. All of these things are steps to rehabilitate the car to a healthy baseline for years of trouble free use.

So, you think I should just clean the PCV rather than replacing it all? I've read that you can get away with cleaning it if it's not too bad but that you still need to replace all the hoses because they often get hard and brittle. Any idea what I should buy? Either way this is all useful information.

[FireFox31]

1. Read some PCV articles here and check YouTube, specifically for an 850 so you know what parts are involved.
2. Go to VolvoPartsWebStore.com. Enter your year, model, and specs.
3. Browse for the part numbers that you need.
4. Find and buy the parts at FCP Euro (common parts) and either VolvoPartsWebStore or Tasca Parts (uncommon parts).

This is my procedure for fixing everything on my car. My recent PCV job took a long time to research the work and find all the parts, but I had what I needed and had no real problems.

[erikv11]

Given the mild symptoms and the mileage I'd gather up the parts like FireFox suggested and then replace the PCV including the intake manifold gasket and throttle body gasket, and change all of the vacuum lines at the same time. This would give you a good baseline where you know there should be very few vacuum leaks anywhere during your ownership. Clean the throttle body and the IAC while you have everything apart, they are likely dirty. Don't get solvent in the TPS when you are cleaning the throttle body. The hoses to the IAC can be hard as a rock and still last a long time working well.

I see your car has SAS, you'll want to check those vacuum lines too and make sure the check valve still works.

Where did those plug wires come from? They may be fine but for P80 cars I have gone with strictly Bougicord, even on NA engines.