PCV Valve vacuum leak?

Bonsuego · Post by **Bonsuego** » 06 Mar 2012, 12:49

My mechanic tells me that my check engine light is on due to a PCV Valve/vacuum leak. I'm currently driving a 1997 Volvo 850. he wants 300 bucks to fix the problem, but I think i can get it done elsewhere for a good deal cheaper. Is replacing the PCV valve itself all you need to do in order to rectify that sort of problem? Or do you need to replace the hose that connects to the PCV valve as well?

Thanks in advance!

Post by **RobTheModd** » 06 Mar 2012, 12:53

Do you know the code it is throwing?

If not get it checked at autozone, or somewhere similar for free.

Bonsuego · Post by **Bonsuego** » 06 Mar 2012, 16:53

P0172, if memory serves.

Post by **rspi** » 06 Mar 2012, 17:48

The bad side of the PCV is that it gets clogged if not serviced properly and can cause massive oil leaks.

On the easy side of the system is that you get codes when you have vacuum leaks. You can usually find the leaks yourself. Check all the vacuum hoses and intake tube for leaks. If you have a car that is NOT turbo, check the flame trap (replace it). When I had the code, my small vacuum line at the back of the intake tube was loose. The car I looked at today had a massive leak at the intake tube just behind the MAF, it was 1/2 off the intake.

Post by **jblackburn** » 06 Mar 2012, 23:28

P0172 is ALWAYS this hose - just behind the power steering pump. Here's how I fixed it when the stupid little elbow broke off on mine.

That space is tight and designed for people with hands the size of a 4 year old.

That said, the PCV system is probably clogged. Pull out the oil dipstick at idle and look for smoke puffing out of the tube. That indicates a clogged PCV system.

There is no simple PCV "valve". Instead, it's a needlessly complex system that's a royal pain in the butt to replace:
https://www.matthewsvolvosite.com/forums ... =1&t=28487

staansS70 · Post by **staansS70** » 26 Jul 2012, 22:33

jblackburn wrote:P0172 is ALWAYS this hose - just behind the power steering pump. Here's how I fixed it when the stupid little elbow broke off on mine.

That space is tight and designed for people with hands the size of a 4 year old.

I've been messing around trying to get my new vacuum elbow installed and I just can't get in there and do it, in your picture am I missing something or is that an additional piece of hose? the replacement part I got was this.

Post by **jblackburn** » 26 Jul 2012, 23:37

It can be a real pain in the ass to reach. I had to remove the upper radiator hose - which just made everything slippery - in order to even get my hands in there. The next time it fell off, I bribed my girlfriend with cheesecake if she'd help me reconnect it with her tiny hands.

I added on a small piece of vacuum hose to mine as an extension, as the other hose fell down and couldn't be pulled up again to where I wanted it within the space confines I was trying to work in.

staansS70 · Post by **staansS70** » 27 Jul 2012, 09:10

jblackburn wrote:It can be a real pain in the ass to reach. I had to remove the upper radiator hose - which just made everything slippery - in order to even get my hands in there. The next time it fell off, I bribed my girlfriend with cheesecake if she'd help me reconnect it with her tiny hands.

I added on a small piece of vacuum hose to mine as an extension, as the other hose fell down and couldn't be pulled up again to where I wanted it within the space confines I was trying to work in.

Thanks for reply and I did same thing with coolant hose and it was very slippery. What end did you add the small piece of vacuum hose? from the intake? or other end

Post by **jblackburn** » 27 Jul 2012, 09:28

It's attached to the end of the existing hose coming from the PTC valve at the back by the turbo.

If that hose is no longer there, then get some vacuum hose and run it from that intake port straight over the top of the engine, back to the turbo area.

staansS70 · Post by **staansS70** » 27 Jul 2012, 09:54

jblackburn wrote:It's attached to the end of the existing hose coming from the PTC valve at the back by the turbo.

If that hose is no longer there, then get some vacuum hose and run it from that intake port straight over the top of the engine, back to the turbo area.

My bad, I didn't realize this thread concerned a turbo, mine is non turbo, does that make a difference? Here's a picture similar to what I'm working with (Note the arrow)