Reducing Oil into Intake Via Stock PVC System
This PVC modifaction installs in-between the intake manifold and plastic hose stock PVC used to plug into.
The only tools you'll need will be a wrench with a 10mm socket and extension and a flat head screwdriver.
(Note: on the C5, it will be necessary to remove the passenger side fuel rail cover.)
Remove the wire clip that is connected to the narrow end of the PCV valve boot. Just pop the metal band off the boot.
Next take a 10mm socket and remove the nut, which secures the heat sink wire.
Pull the PCV valve from the tubing connecting to the intake manifold. Now slide back the foam where the PCV valve
boot connects to the hard rubber tubing going back to the valve covers.
Pull the boot off the tubing. You should now be holding the PCV valve boot with the valve inside, and the heat sink wire hanging off. You can slide the heat sink out of the boot, but remember its orientation. Now pull the PCV valve out of the boot. It's easiest if you pry the edge of the boot back from the ridge on the valve. Start at one point and
just work your way around the circumference of the valve. Once this is done, just pull and twist on the valve until it works it’s way out of the boot.
Now take the heat sink wire and re-attach it to the boot. However, you need to slide the band back in the opposite
orientation from how it was originally installed. This will allow you to reinstall the wire and nut even though the valve will be in a different position.
Now take the pre-assembled section with the tee and connect the 1-3/4 length of tubing to the hard plastic tubing from
the valve covers.
The catch can will lay in the space between the block and the thermostat hose.
Now take the pre-assembled section with the PCV valve and install the boot onto the valve.
Install the other end of the boot onto the top of the tee. Reinstall the wire clip to the tubing and reconnect the heat
sink wire nut. The elbow on top of the valve should be facing the rear of the engine bay. The 3/8 connector nearest the valve will have an exposed edge in the center. Slide it into the spare
groove on the throttle cable bracket.
(Note: this doesn't apply to the C5, which doesn't have a throttle cable bracket. On the C5, the filters will be hidden
under the fuel rail cover.)
Take the end of the tubing with the universal connector and route it between the middle injectors. Loop it back to
the intake manifold and insert the connector into the manifold tubing.
The manifold tubing has a slight angle on it.
You will need to hold it straight to get the connector to slide all the way in.
Finally, get some throttle body cleaner and clean the oil off the throttle body. Reinstall the air lid, MAF sensor, and
throttle body tubing.
(Note: on the C5, reinstall the fuel rail cover.)
That's it. This should prevent any oil from getting into your intake manifold. To verify that this is the case, you
can pull the tubing at the connector at the intake manifold to make sure there's no oil on it. Don't worry if you see a little oil in any of the three filters. That's what they're there for.
You'll want to make sure that this modification hasn't created too much of a pressure drop through your PCV
system. To do this, start the car and let it idle. Pull the fresh air tube from the connection at the throttle body. Stick your finger at the end of the tube... you should feel some suction. It won't be nearly as much as before the
modification, but it should be noticeable. If not, the pressure drop is choking the flow. To correct it, remove the universal elbow and cut off the smallest ends like you did originally. This will present the next diameter size to the air
stream and improve flow.
The PCV system draws air from the rear of each valve cover to the
intake manifold. Fresh air is provided from a tube connecting the front of the passenger side valve cover to the throttle body. The factory arrangement results in oil being sucked from the valve covers into the intake manifold. You can
see for yourself by removing the PCV valve and by looking behind the blade of the throttle body.
You'll notice oil in both areas. This oil is being drawn into the combusion mixture, resulting in carbon deposits, plug fouling, and pinging.
Some LS1 owners have eliminated their oil consumption through the PCV system simply by reworking the PCV valve to be in a vertical position. We did this on our Trans Am, but oil was still getting into the intake manifold. This modification prevents this, while retaining the forced evacuation of the valve covers, and has a fairly stock appearance.
Install Images Slideshow
Parts list:
2 Deutsch fuel filter,
PN FF314, $1.99 each
1 Deutsch fuel filter, PN FF407, $2.99
1 Deutsch PCV valve, PN PCV199, $2.99
1 Deutsch PCV valve, PN PCV183, $1.59, or PN PCV260,
$1.99
2 Vacu-Tite 1/4" x 3/8" connector, PN
47306, $1.79 each
1 Vacu-Tite universal connector, PN 47309, $1.49
1 Vacu-Tite universal tee, PN 47349, $1.49
1 Vacu-Tite 5/16" rubber cap, PN 47394, $1.49
1 ft 1/4" fuel/emissions tubing, $0.79
3 ft 3/8" fuel/emissions tubing, $$2.37
Flat black paint (optional)
Total cost: Approximately $24.00 with tax
The Deutsch fuel filters and PCV valves can be
found at AutoZone. The Vacu-Tite parts and tubing
can be found at any auto parts store. It has been
our experience that Advance Auto carries the 1/4"
x 3/8" connectors and AutoZone does not. It
has also been our experience that Advance Auto is
consistently more expensive for an identical
item, so when possible, we get everything but the
1/4" x 3/8" connectors at AutoZone.
The reason that two part numbers are listed for
the second PCV valve is that you won't be using
the valve itself. You'll just be using the
plastic 90 deg elbow. PN PCV183 is less
expensive, but if it's out of stock PN PCV260
also has the plastic elbow.
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