Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Blowing oil out of the breather!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by stickshooter, Apr 3, 2003.

  1. stickshooter

    stickshooter Registered Member

    Joined:
    Oct 26, 2001
    Posts:
    23
    Likes Received:
    0
    Ok, I did a search and couldn't find the answer I needed so here goes.

    I couldn't get my cheap Mr. gasket chrome vlv covers to stop leaking so I picked up a nice looking set of aluminum Holley covers at the local pro shop along with a nice set of extra thick cork gaskets and new rubber grommets. A PCV valve is installed in the drivers side front hole, a non breathing oil filler cap is in the passangers side front hole, and a breather with a rubber grommet made for a non baffled valve cover is in the passenger side rear hole, basically an enclosed rubber grommet with a slit cut in the bottom. The breather fills up with oil and drips on the headers after a short trip down the road. PCV valve is new, I tried two different brands of breathers. I requested a stock oil pump when I put this engine in about a year ago, but with 10w 30 oil, when it's warm I have about 40 psi at idle, any amount of rpm increase and the needle slams to the peg...60psi +? I don't know if that's relevant or even if the stock gauge is accurate, but I thought it might be.

    Incidentally, the valve covers don't leak any more, but the breather, which was installed in the FRONT passenger side on the old covers and used as the oil filler cap didn't blow oil out in the old application.

    I get blank looks from local mechanics and the people at parts stores are generally clueless.

    Thanks

    I should add, I can not find any type of baffle system, grommet or otherwise for the PCV valve. Both the breathers I've used were the baffle type and on the last one I took the time to position the baffle so that oil coming up and hitting it would slide back down into the valve cover instead of hooking over into the filter media.
     
  2. caryhenry

    caryhenry Registered Member

    Joined:
    Sep 28, 2002
    Posts:
    78
    Likes Received:
    0
    Location:
    Tallahassee, Fl
    I'm not sure what year or engine you have, but on my 85 305, the pcv valve is on the rear passenger side and on the front driver's side I have a vacuum air port.
     
  3. CamaroZ85

    CamaroZ85 Registered Member

    Joined:
    Feb 21, 2003
    Posts:
    27
    Likes Received:
    0
    Location:
    Woodbridge NJ
    So your valve covers do not have baffles in them, correct?
    I would imagine either that grommet claims to do something it cannot, or you have way too much crankcase pressure for the pcv to evacaute and therefore it needs to find other means to escape. Are you actually getting vacuum to the pcv? Also, I'm assuming that the pcv isn't baffled as well, maybe that is filling with oil and quitting on you. Is the pcv new? Can you hear the pintle move when you shake it? How old is the motor? Maybe the drainback holes in the head are very plugged. If you're moving a big volume of oil, and the drains are working slower than the pump, you could be filling up the whole valve cover w/o realizing it. That could explain why you couldn't get the last one to stop leaking. How old is the motor? Maybe your rings are going and you're getting some blowby, causing excessive crankcase pressure. In time that would load up the breather with oil and cause the same problem. To chekc this you usually start the motor and pull out the pcv vavle. If you're getting a nice puff of oil smoke coming out of the pcv hole you know something is up. Lastly, if its a new motor maybe the rings just havent had time to seat yet. If it's new, I hope you're not breaking it in with synthetic oil because it takes way longer for the rings to seat properly that way. Hopefully I'm touching on a few things that will make you think and maybe figure it out. Oh yeah, I'm a parts store guy too /forums/images/graemlins/tongue.gif
     
  4. chiefKP

    chiefKP Registered Member

    Joined:
    Mar 17, 2000
    Posts:
    16
    Likes Received:
    0
    Location:
    Pyongtaek, Korea
    The exact same thing happened to me last year. Here's what I discovered. The pushrod wich activates the valve rocker directly beneath the breather hole was worn. The oil port on the pushrod that contacts the valve rocker had worn abnormally and the machined tip had rubbed off. The wear caused the oil port to be enlarged. The additional flow of oil passing over the rocker was splashed directly into the breather causing the leak.

    Take a look at the pushrod directly under the breather. I'll bet you find the end chewed up. It may be time for new pushrods and rockers.

    It took me pulling the engine and the heads to find this. Very painful. But, I also discovered broken rings on three pistons. I'm still recovering.
     
  5. k20

    k20 3/4 ton status

    Joined:
    Sep 9, 2001
    Posts:
    5,068
    Likes Received:
    0
    Location:
    Mineral Springs, NC
    if the motor is old, and u put something besides that breather in, ill bet oil comes pumping up the dipstick. Thats what mine did still does, but i solved it by taking out the non breathing oil cap, and putting in a breather. But of course the other two holes in my valve covers are a pcv valve, and some other type of vent. Probably rings are bad or havent seated. Try removing the cap, if theres a breeze coming out, then its rings, and to get it to last till a rebuild i would try a breather in place of the oil fill cap, giving you two breathers.
     
  6. stickshooter

    stickshooter Registered Member

    Joined:
    Oct 26, 2001
    Posts:
    23
    Likes Received:
    0
    I put the engine in about a year ago, wasn't on the road until last June. About 3000 miles on it since then, I'm guessing as I just got the speedo fixed. I did take it a thousand mile round trip to S. TX this spring though. I'm ashamed to say, it's a remanufactured engine I bought at a local supply house, other than that, I've tried to use quality parts on everything.

    It's a '81 K5, I swapped the 305 for a 350. PCV is in the same location as the original and if I remember correctly, there were no other vents on the stock valve caps. I have removed all the pollution stuff though.
     
  7. k20

    k20 3/4 ton status

    Joined:
    Sep 9, 2001
    Posts:
    5,068
    Likes Received:
    0
    Location:
    Mineral Springs, NC
    yeh mine has a ring around the tbi with a hose going into the rear hole on the drivers side valve cover
     
  8. BRN78BLAZER

    BRN78BLAZER 1/2 ton status

    Joined:
    Feb 5, 2003
    Posts:
    133
    Likes Received:
    0
    Location:
    Stoney Creek Ontario, Canada
    I think the chief might be right. Mine does the exact same thing as you described, and gets a lot of lifter noise coming from right beneath the breather! /forums/images/graemlins/shocked.gif Don't know if this helps you, but it helpped me /forums/images/graemlins/grin.gif Thanks Chief
     
  9. CamaroZ85

    CamaroZ85 Registered Member

    Joined:
    Feb 21, 2003
    Posts:
    27
    Likes Received:
    0
    Location:
    Woodbridge NJ
    [ QUOTE ]
    yeh mine has a ring around the tbi with a hose going into the rear hole on the drivers side valve cover

    [/ QUOTE ]

    Thats your breather...the TBI trucks were set up that way, and carb trucks just had it going into the air cleaner. factory breathers vent into the air intake system but you can buy aftermarkets that vent into the atmosphere
     
  10. stickshooter

    stickshooter Registered Member

    Joined:
    Oct 26, 2001
    Posts:
    23
    Likes Received:
    0
    The engine has maybe 3000 miles on it, and while I'm sure that it could have some push rod problems as it's a rebuild and not new, that's really the last place I would look. The PCV valve is functioning,has maybe 100 miles on it, and is in the stock location. Does anyone else's oil pressure gauge peg the needle at anything over an idle with a stock oil pump? Could it be an oil pressure problem or is ita crankcase pressure relief problem. I know they're related, but one is obviously off. This engine is still under warranty and I'm trying to make sure I'm not doing something stupid before I take it to a mechanic and try to get it warrantied. Help is appreciated.
     
  11. 70~K5

    70~K5 1/2 ton status

    Joined:
    Apr 13, 2002
    Posts:
    2,032
    Likes Received:
    0
    Location:
    sillycon valley
    If there's not a baffle under the opening you need one..
     

Share This Page