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.

Still another leak

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mouse, Apr 15, 2005.

  1. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    I rebuilt the engine a couple of weeks ago, I have all the leaks taken care of but one. I guess that what I get for buying a cheap gasket set...

    I have a leak at the rear of the engine. There is a bit of oil on the starter, and some on the trans dust shield. I replaced the oil pan gasket again, this time with the one-piece Fel-pro gasket (its nice!). But the leak remains. The rear main seal is nice and dry. I guess I'm down to valave cover gasket (I'm using rubber gaskets that have the steel reinforcement) or an oil galley plug on the back of the block. Its hard to tell with the clean engine and clean oil.

    Any tricks to narrowing down? A guess to what it might be? I'm a little short on time to look at it close this week. I don't feel like pulling the engine again. I guess this time it will be the trans, if I can't locate it...
     
  2. Cricket

    Cricket 3/4 ton status

    Joined:
    Nov 29, 2004
    Posts:
    8,224
    Likes Received:
    0
    Location:
    Colorado
    You can try carefully dusting with a small amount of baby powder. Just keep it out of the intake.

    Did that to locate a trans leak and it worked well.

    ADDY: always had problems with hard to see leaks at the rear edge of the valve cover. Run your finger under there and see if you get oil on the tip.
     
  3. 85HeartBurb

    85HeartBurb 1/2 ton status

    Joined:
    Jan 10, 2002
    Posts:
    735
    Likes Received:
    0
    Location:
    Temecula, south
    I just finished helping my buddy find his leak it sounds similar to what your experiencing I felt on the back of the engine come to find that the back of the intake manifold gasket had blown out so it was coming from there!!!
    hope that helps..... :D
     
  4. trailblazer86

    trailblazer86 1/2 ton status

    Joined:
    May 16, 2004
    Posts:
    112
    Likes Received:
    0
    Location:
    North Shore of Lake Ontario
    I have had this happen also.
    The first time it was the distributor gasket.
    The second time was when I learned that silicone and gaskets were not meant to be used together.
    The Rocker cover gasket "squirmed out" due to the use of silicone.
    Lesson learned; Either use one or the other… Not both.
     
  5. 89GMCSuburban

    89GMCSuburban 1/2 ton status

    Joined:
    Nov 15, 2001
    Posts:
    3,005
    Likes Received:
    0
    Location:
    Thornton, CO
    I'm going to second the distributor gasket. Also look at the brass fitting that T's into the block for your oil pressure sending unit. Those get ragged from removal and leak.
     
  6. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    Some great ideas to check. The intake and sending unit "looked" clean, but who knows without feeling since its fresh oil.

    Thanks.
     
  7. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    It looks like the leak is from the passenger valve cover. I found fresh oil (enough to fill the end of my finger) on the back lower corner, directly over the starter. It is dripping straight to the starter, which made it hard to find.

    These old valve covers are bent, and are in poor shape. Do you think I can get a good seal with the GM performace stamped covers (they claim heavy duty construction) or spend the extra $$ on the cast aluminum?

    I hate oil leaks!
     
  8. Cricket

    Cricket 3/4 ton status

    Joined:
    Nov 29, 2004
    Posts:
    8,224
    Likes Received:
    0
    Location:
    Colorado
    I went with the steel GM covers from Summit but I also added the longer chrome retainers that go on the 4 cover studs. They are much bigger than your small stock retainers and should help improve the seal.

    I have never owned the aluminum covers so I can't be of any help there.
     
  9. muscle

    muscle 1/2 ton status

    Joined:
    May 28, 2000
    Posts:
    408
    Likes Received:
    0
    Location:
    Show Low, AZ
    I use the edelbrock cast aluminum valve covers. (i use the ones without the edelbrock logo they are cheaper sold at Summit )

    Ive used stamped steel and will never go back. Its worth the extra money because of one less headache and they look great. If your leak is small I would endure with it a little longer to save a few more pennies for a better item.
     
  10. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    You guys talked me into it. I ordered the least expensive cast aluminum covers I could find - the summit brand covers at $62.95ish. I don't need (or like) the extra shiny polish look, but its something I can deal with. After all, I wouldn't want to be accused of building a show truck!
     
  11. 6.2 man

    6.2 man 1/2 ton status Premium Member

    Joined:
    Feb 17, 2000
    Posts:
    636
    Likes Received:
    1
    Location:
    Curtis , WA
    I found something other than valve covers that work great !!!!I use those edelbrock performance valve cover clips !!! Thet are a long bar with a hole to go into where the valve cover bolts down . they are chrome and about 3 inches long ? You see them in all the parts stores . I have used those on a number of 350's including my own and never had a leak !!!
     
  12. muscle

    muscle 1/2 ton status

    Joined:
    May 28, 2000
    Posts:
    408
    Likes Received:
    0
    Location:
    Show Low, AZ
  13. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    Those look nice. I bet they'll never leak!
     
  14. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    Well I installed some Summit cast aluminum valve covers and there is absolutely no leak on the valve covers. The black rubber gasket is nice and dry all around.

    But

    I still am getting oil on the starter and down into the tranny dust cover. There is a little oil on the bottom off the passenger side exhaust manifold. I got a new distributor gasket, as the old one (1 yr old) looked wet.

    My list as to possible causes of this leak is getting short. Recap: new oil pan gasket, valve covers, and distributor. Whats left: intake, rear main, and head gasket.

    With a flashlight the intake looks dry. Run my finger on it-feels dry.

    Rear main is the only thing that looks dry under the dust shield. Oil is primarily on passenger side.

    Head gasket-the engine runs great. I have no miss. I could hook up the compression tester...

    I idled the engine for 45 minutes waiting for it to leak after changing the valve covers - nothing... Went for a drive, came home, parked, and the starter was dripping with oil. Not a steady drip, but wet, and enough where I'm starting to get a oil stain on the concrete driveway. I guess it only leaks when warm and the engine is at the highest oil pressure. I am running a high volume oil pump, with a resulting higher pressure too.

    I think its the crappy Summit gasket set I bought. All I've replaced have been with Felpro.

    Ideas?
     
  15. muscle

    muscle 1/2 ton status

    Joined:
    May 28, 2000
    Posts:
    408
    Likes Received:
    0
    Location:
    Show Low, AZ
    did you eliminate the oil sending fitting at the rear of the intake on the block that supplies the oil pressure guage?

    The only areas i can think of are those already listed. As you can see on the pic the rear of the blok makes a nice channel for oil to run down on either from the intake, oil guage fitting, or distributor.

    01010005.JPG
     
  16. muscle

    muscle 1/2 ton status

    Joined:
    May 28, 2000
    Posts:
    408
    Likes Received:
    0
    Location:
    Show Low, AZ
    also if the oil is new it would be very hard to see where its coming from. I still wouldnt rule out the valve cover ast a small leak on the cover just above the header or manifold could get past you
     
  17. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    I can get a good look at the oil sending unit, its dry. Any chance of a head gasket? I think this weekend I'll start by pulling the intake and go from there. If its not obvious, off go the heads.

    Yeah, its new oil. I changed it 3 times since putting the engine in - about 300 miles. I run it this week and see where it gets wet. The front drive shaft is getting "lubed" now as well.

    I would love it to be a valve cover gasket. I've got a couple of cheap cork gaskets laying around. Its free, so its worth a try...

    Maybe I'll get some pics up...
     
  18. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    Heres the leak. Kinda hard to get the camera angle right, but you can see it.

    Plus, a bonus shot of the new (and already dirty) valve covers - not bad for $65...

    leak.JPG

    valve covers.JPG
     
  19. muscle

    muscle 1/2 ton status

    Joined:
    May 28, 2000
    Posts:
    408
    Likes Received:
    0
    Location:
    Show Low, AZ
    valve covers look nice :thumb:

    sorry but I think it has to be a valve cover gasket leaking or rear intake manifold. I just cant see a head gasket leaking oil by without other symptoms. and i would not rule out the oil pan gasket. ill be curious to see what you find out
     
  20. Cricket

    Cricket 3/4 ton status

    Joined:
    Nov 29, 2004
    Posts:
    8,224
    Likes Received:
    0
    Location:
    Colorado
    Drop your starter and flywheel/converter cover then try and trace up.
     

Share This Page