PVC on my CAI.. [Archive] - GrandAmGT.com Forum


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young gun
08-03-2012, 02:31 PM
For starters I don't fully understand the PVC system..

But there is oil getting around...
Hard to see but the PVC to the rear valve cover has oil about an inch and a half up the pipe.

PVC grommet has a crack in it should that be replaced first and see what happens?

EGR blocked off with the LX9 swap if that helps at all

08-03-2012, 04:54 PM
That's not the pcv valve. It's the rear crankcase vent but I have no idea why oil would be all over everything like that. Is your pcv valve working?

young gun
08-03-2012, 05:38 PM
lol I'm dumb.

Well I don't have any codes so I'm assuming it is working

08-03-2012, 07:42 PM
lol I'm dumb.

Well I don't have any codes so I'm assuming it is working

I don't think it will throw any codes but I could be mistaken. I'd replace it anyway since it's dirt cheap and it may be clogged. I can't really think of any other reason that would be throwing that much gunk everywhere. Maybe a veteran member can come up with something else lol this is my only guess.

08-03-2012, 07:52 PM
There are no codes for the PCV system. ;) It has no sensors.

It's a pretty simple system, and has been explained on here before.

During engine operation, there is blow by from the cylinders that slips past the piston rings and into the crank case. It contains hot combustion gases with small amounts of fuel and contaminants from the combustion process. These will mix with oil mist in the crank case from the spinning crank, and when the engine stops and cools down they will mix with the oil. The goal of the PCV system is to evacuate these gases from the crank case to keep the oil clean and not affect the viscosity. The engine will reburn these gases as fuel, and it also pulls some of the oil mist into the intake in the process. That's why I think all cars should have an oil catch can to cut down on the amount of oil that gets in the intake, and don't know why manufacturers don't include them. As it is, between the PCV and EGR the intake just gets gunked up with carbon and sludge. Anyway...

A tube runs from the intake manifold right behind the TB to the PCV valve on the front valve cover. When the throttle plate is closed the UIM is under vacuum, and this pulls gases from the crank case up through the engine and cylinder heads into the valve covers and out the PCV valve. The tube on the rear valve cover provides fresh air from the intake, after the MAF sensor so it has been metered and accounted for, to go into the crank case to replace the gases pulled out. It's a full circulation system basically.

The PCV valve meters the flow to the intake, and also stops flow reversion. When you are at WOT and there is no vacuum, the increase in combustion pressure and blow by usually increases crank case pressure enough to flow out on it's own. If the blow by is excessive though, or if the PCV valve or line are dirty or otherwise not flowing enough, the excess flow will go back out the rear intake line. That's probably why you've got oil on that line. That, and the rear tube usually doesn't fit that tight in the valve cover, so it could be leaking around it a little.

You could try cleaning and/or replacing the PCV valve and front line. You could also try replacing the rear line or putting some RTV around the hole to try and seal it up better. You could also put a vacuum check valve in the rear line to make sure the flow only goes into the rear valve cover and not back out, but it's probably not necessary.

young gun
08-24-2012, 11:57 AM
Well I got lazy and didn't do anything for a bit but I today to do whatever so I went out again and took a peek. Found out that the LX9 rocker cover I have doesn't have a PCV valve in it. Searched 60v6 and found this bad boy (http://60degreev6.com/forum/showthread.php/48091-3500-%28LX9%29-PCV-System).

So I think I will try an inline PCV valve...After I look more into how exactly to do it