Pcv Blows Out At High Rpm

Discussion in 'Fox 5.0 Mustang Tech' started by Bretts0032, Aug 12, 2017.

  1. my pcv valve blows out at high rpm spraying oil everywhere. I've read everything I can and everything I see is all on boasted cars. Mine is a 347 stroker non boosted. I've replaced the grommet replaced the pcv valve itself and still have know luck. I've read about the pcv balance delete and the 2 breathers and so on I just want to fix the problem and be done with it. Any advice would be appreciated
  2. Balance was a typo sorry
  3. I am going to move this to the tech threads, someone there will help you out, if not I can always chime in with some really bad advice:jester:
  4. rtv around the pcv valve
  5. My car did this when it had serious blow by(multiple cracked piston ring lands). I put some high temp silicone tape around the pcv grommet to make it an extremely tight fit, this helped with it not blowing the pcv grommet, and valve out. However the oil started blowing out my dipstick tube. Tried breathers just blew oil out of them as well. Do a leak down test if you can.
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  6. ok I'll do that and get back with u.
  7. Do you still have the vent tube between the filler neck and TB?
  8. Yes
  9. @Bretts0032
    Your difficulty is indicative of some fault allowing very high crankcase pressure build-up, as mentioned by @jchav02. This is not a good scenerio, but is partly good in that it develops only at high rpms. Cause(s)? As he said, or cracked piston rings, cracked piston, small hole in piston dome.

    With engine idling, remove oil filler cap and listen carefully at opening. If a rushing, whooshing sound is audible, or vapors are felt coming out, continuing to drive it will only make it worse. Sorry. imp
  10. Just went and pulled the breather cap off the filler neck and vapors are definitely blowing out. What are my options
  11. Remove and rebuild or replace with another engine.
    Or park it out back and drive your mothers mini van :puke:
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