PCV Location

ckrussell · Post by **ckrussell** » 31 Dec 2011, 18:54

Where is the pcv valve on a 1994 850 non-turbo. I let someone look at my car which is having performance issues. They connected the two vacuum lines on the evap canister to bypass it thinking it may run better. Now the oil tube and cap are blowing out smoke. Figuring pcv is plugged...

Post by **precopster** » 31 Dec 2011, 19:57

It is a complex system. On NA models there is a flame trap located in this assembly as per photo.

There are also various hoses which lead to a large plastic collection box under the inlet manifold which is bolted to the block. The ports on the cylinder block which lead to this collection box can become clogged and cause excess pressure to vent through the dipstick tube and through seals which result in leaks.

Remove the flame trap, check it for clogging and clean it (some users remove the flame trap mesh totally)

If you have a lot of pressure through the dipstick tube after cleaning this it will be time for an overhaul of this system.

If you're talking about the evap canister near the driver's side wheel well this system handles FUEL vapours, NOT CRANKCASE VAPOURS.

ckrussell · Post by **ckrussell** » 31 Dec 2011, 20:21

I didn't know if the volvo's had a specific pcv valve as other vehicles do. For some reason, after he jumped the vacuum lines together on the evap canisters, just for a short test drive to see if that was causing the performance issues, the dipstick and oil cap were smoking. It seems strange it happened right afterwards. I am going to go ahead and take apart the whole pcv system and clean it up if cleaning the flame trap is ineffective. Thanks

Post by **precopster** » 31 Dec 2011, 20:31

You can see here the system is not connected in any way to the evap system. I would place them back as they were as you will be inviting new Evap codes to appear before too long.

ckrussell · Post by **ckrussell** » 31 Dec 2011, 20:35

We just jumped them together for a quick 3 mile drive. They are back now.

ckrussell · Post by **ckrussell** » 01 Jan 2012, 12:37

Tackling the pcv job today. Man those bolts on the intake are a pain. Especially the bottom left one...wow. Doesn't help the weather today is brutal. 30 mph wind gusts and cold. Unfortunately my spare volvo is in the garage.

ckrussell · Post by **ckrussell** » 01 Jan 2012, 13:50

Took the oil separator off and the passages were spotless. Ran my fingers through both ports with no blockage. Swapped out separator anyways. Not sure what is causing increased pressure in the system but it doesn't seem to be this system. Egr valve port was clean and valve was operable. Really suprised considering the mileage

Post by **jblackburn** » 01 Jan 2012, 19:45

Hoses and flame trap/PTC hose connections were all clear?

Next step I would do is to check compression. Low compression = lots of blowby = more than the PCV system can handle.

ckrussell · Post by **ckrussell** » 01 Jan 2012, 22:11

The motor is pretty wore out. It sounds like someone dropped bb's down the oil cap. It's been that way for 30,xxx miles which is the entire time I've owned it. I have another motor ready to go when this one lays down. Hope it last til spring!!!