+ Reply to Thread
Page 1 of 7 1 2 3 ... LastLast
Results 1 to 10 of 62

Thread: Crank case pressure (blowing out dipstick)

  1. #1
    Join Date
    Nov 2007
    Location
    S.A. Texas
    Posts
    3,751

    Crank case pressure (blowing out dipstick)

    Ok last night while really gettting on my truck the dip stick blewout. I have both valve covers vented with small filters on top of the vent ports. It seems if i hit full boost after last night blows the dip stick out. It did it again to day. I changed the o ring on the dip stick to see if that helps. Still seems kinda easy to come out. Is there a cure for this or did I screw something up. This happened once also when the valve covers were not vented yet also. Thanks for the help.
    Last edited by SLO TRUCK; 08-11-2009 at 09:25 AM.
    Name: Mark,
    God created turbo lag so nitrous trucks could have a chance.


    http://www.ls1truck.com/forums/my-ga...tml#post274877

  2. #2
    Join Date
    Aug 2004
    Location
    Magnolia, TX
    Posts
    3,259
    do you have a catch can?

  3. #3
    Join Date
    Oct 2008
    Location
    Houston
    Posts
    807
    This is blow-by past your piston rings causing this.
    Not much you can do about it.

    Racer's use crank case vacuum pumps, but they not very street friendly components
    and tend to have high rebuild rates.

    It's not a good sign either. ..........
    2002 Tahoe 4.8 - soon to be turbo'd - SOLD
    1989 Mustang - LX Vert - 351W-TT - 2inches of dust covering it
    2012 Raptor - 497rwhp at 10psi
    If you aint breaking - you aint going fast enough

  4. #4
    Join Date
    Jul 2008
    Location
    Racoon Twp., PA
    Posts
    1,572
    Quote Originally Posted by r.barn View Post
    This is blow-by past your piston rings......

    It's not a good sign either. ..........

    x2
    2013 CC 5.3
    81 C10 LS1 project

  5. #5
    Join Date
    Nov 2007
    Location
    S.A. Texas
    Posts
    3,751
    coming out the dip stick is, past the piston rings? i thought that would be when it came out of the valve covers.
    I dont have a catch can set up. Would that make any difference since it's coming out the dip stick? As stated both valve covers are vented.
    Guess it's time to go easy one it for the next month since i am in Louisiana at work running around in ti constantly. SO is this the end of my lil engine?
    Name: Mark,
    God created turbo lag so nitrous trucks could have a chance.


    http://www.ls1truck.com/forums/my-ga...tml#post274877

  6. #6
    Join Date
    Nov 2006
    Location
    Mesquite, TX
    Posts
    4,321
    take your oil cap off and put a filter on that, i had the same prob...the little vac lines on the valve covers weren't nearly enough
    2006 silverado SS....Clifford Jr...turbo coming soon
    1970 Chevelle ly6 swap....d1 coming soon

  7. #7
    Join Date
    Oct 2008
    Location
    Houston
    Posts
    807
    Valve cover breathers cant keep up.
    Pressure has to work thru entire engine up to breathers where as
    dipstick tube goes right down into crank case.

    If it was pushing out dipstick in N/A form before valve cover vents
    then its been around for a while.

    It's not the end of you engine, but it is the beginning of the end.
    I'd start planning for a short block rebuild in near future.

    Only thing that will help right now is to seal valve cover breathers and put
    a crank case vacuum pump on to put a positive vacuum on the crank case
    at all times. This will suck out the blow-by before it builds pressure.

    I wrestled with this on my 5.8L mustang ... on brand new engine no less
    and finally just had to take it apart and re-ring and re-hone the cylinders.
    2002 Tahoe 4.8 - soon to be turbo'd - SOLD
    1989 Mustang - LX Vert - 351W-TT - 2inches of dust covering it
    2012 Raptor - 497rwhp at 10psi
    If you aint breaking - you aint going fast enough

  8. #8
    Join Date
    Oct 2007
    Location
    Bandera, TX
    Posts
    2,921
    ol lucky #7......
    single digit street truck


    for build info

    http://www.ls1truck.com/forums/my-ga...cs-garage.html

    The best advice I have ever heard:... Only take B( . Y . )ST advice from someone that is CURRENTLY running a turbo setup close to, or bigger than what you want......

  9. #9
    Join Date
    Oct 2008
    Location
    Houston
    Posts
    807
    Might not need complete rebuild. Honing, new rings and bearings might be
    enough, but you never know until open her up and see what you have.

    We never could figure out why my Windsor did it. But you could definitely
    see it on (2) cylinder walls where the rings hadn't seated properly for whatever
    reason.
    2002 Tahoe 4.8 - soon to be turbo'd - SOLD
    1989 Mustang - LX Vert - 351W-TT - 2inches of dust covering it
    2012 Raptor - 497rwhp at 10psi
    If you aint breaking - you aint going fast enough

  10. #10
    Join Date
    Feb 2007
    Location
    Spring, Texas
    Posts
    1,739
    Same thing was happening to mine when I cracked a ringland on #7....

    Doesn't sound good...

    I would do a compression check ASAP and see if there's an issue. If it comes apart it will do more damage than a honing will fix...

    2004 Silverado Crew Cab, forged iron 5.7, STS w/MP turbo, 10+ psi, FMIC, Tial 50mm BOV, Vic Jr, Snow performance meth, MTI Stealth cam .220/.220 .581/.581 115lsa, Comp chromoly pushrods, Yank TT3000 stall, LS1 Efans, 160 tstat, Trucool 40k trans cooler, 60# injectors, Walbro fuel pump, Patriot springs, Built 4l65E w/billet input & output shafts, Eaton posi, SD tuned...all installed by Klein North Automotive

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts