Hey everybody

So I just did a boost leak test on my car after installing new intercooler and piping. I fixed some major leaks and dont seem to have any smaller leaks anywhere else. Now my only problem is I believe the PCV valve that vents to the intake manifold is leaking. I can pressurize the intake system to 25 psi no problem but pressure leaks out at about 1 psi/second. I can hear air coming out through the oil fill on the valve cover. Should I replace the PCV valve?

 

Yes you should replace it, preferably with an OE unit or a check valve. Mmost aftermarket options such as those sold in auto parts stores leak boost. I went with a 3/8" in-line check valve instead, this is probably a better option if you're going to be running higher boost pressure.

 

Okay thanks. I figured I needed to, so I ordered an OEM valve from map. Down the road I plan to get a VTA catch can setup and delete the PCV's. Is there any downsides to doing this?

 

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You need pcv for a variety of reasons.

1. pcv keeps the engine clean. It keeps combustion byproduct out of engine oil, reduces contamination over time (sludge or partially reacted alkane chains)
2. pcv improves piston ring seal which further enhances/emphasizes #1, improves efficiency and economy, and for vacuum pump style engines improves power output

3. pcv during boost pressure (by utilizing pre-compressor inlet or other sources) helps prevent oil leaks by keeping crankcase pressure low or negative (below atmospheric). In other words, pcv prevent oil leaks from seals (front/rear main, valve cover, timing cover, oil pan, etc...) due to crankcase pressure.

Every performance engine should have some form of below atmospheric crankcase draw for during WOT and cruise.