Head Gasket with Gasket Sealer?

Discussion in 'Airheads' started by sh1bby69, Oct 3, 2012.

  1. sh1bby69

    sh1bby69 Been here awhile

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    Just installed new valve cover gaskets and torque to specs according to Clymers Manual and the cylinder heads are leaking...it didn't call for gasket sealer should I have used it? I'm on my way to get new gaskets cause I found out I also pinched the cylinder base ORing.

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  2. Disston

    Disston ShadeTreeExpert

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    Head gaskets do not get any sealant. The base of the cylinder might but I don't have a modern machine so I don't know. The head gaskets though never get sealant. If the head is not sealing there is damage to the sealing surface on the head or on the cylinder. Look at them carefully. This is not really a rare problem but hopefully next time you look more carefully because of this time.

    The mating surfaces have to be clean and dry. They can leak because old gasket material was not cleaned off.

    Sometimes a damaged part or surface can be fixed using a file. Better take a picture of any problems you find and we''l tell you, hopefully, if you can do it yourself or it has to go to a machine shop.

    The surfaces have to be flat. You need a known flat surface to check the head surfaces and the cylinder surfaces on.

    Did you torque everything properly? The torque value to use for final cylinder head torque is 25 ft/lbs. Any other figure from another source especially Clymers or the BMW Shop Manual, ignore. It's 25 ft/lbs in 3 stages. You get to do a re-torque after 1 or 2 hundred miles.
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  3. sh1bby69

    sh1bby69 Been here awhile

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    Yea everything was torqued according to the clymer manual. The head gaskets never leaked before. And I tried my best cleaning it even using a gasket cleaner and a plastic scraper.

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  4. Disston

    Disston ShadeTreeExpert

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    So if it is leaking from the head to cylinder junction you will now have to take it apart.

    You might like this one. I noticed the push rod tube rubbers or the base of my cylinders have started leaking on my R90/6. I'll probably get another look at it sometime next week. Don't wanna rush things.
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  5. sh1bby69

    sh1bby69 Been here awhile

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    Yea its only one side that I pinched the O-Ring but both sides have the leak in the cylinder head. I don't want to over torque it though

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  6. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    Could it be the valve cover gaskets leaking and not the head gaskets?
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  7. sh1bby69

    sh1bby69 Been here awhile

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    Sorry yes the valve cover gasket.

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  8. bmwrench

    bmwrench Long timer

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    Chances are your cylinder heads are warped; this is a chronic problem on late model Airheads. Remove the gaskets and put the covers back on. You'll probably see gaps above and below the valve chambers. The best solution is to have the surfaces remachined, but you can get around it by putiing a bead of silicone under the valve cover gasket at the gaps or using silicone gaskets.

    They didn't leak previously because the gasket slowly conformed to the heads as they warped.
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  9. sh1bby69

    sh1bby69 Been here awhile

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    I'll give that a shot.

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  10. supershaft

    supershaft because I can

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    Cronic problem on late model airheads? I have seen early model heads warp just as much if not more.

    Same thing with lifter pitting. I see it happening to lifters across the board. I see it happening to relatively new lifters about as often as older ones. I certainly do not see it largely limited to a couple of years of one model. Not is the slightest.

    Just saying to get a different observation out there.
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  11. bmwhacker

    bmwhacker Still on 3 wheels

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    I had leaking valve covers too....I ended up putting 2 gaskets on each side with no sealant...took care of the leaks.
    Probably not ther right way but it worked. I check valve clearances fairly often so didn't want to use sealant.
    #11
  12. AirGsPd

    AirGsPd Dream Rider

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    I am wondering how you know that you pinched the cylinder base o-ring. I just re-sealed my engine and have not had the chance to run it. Did your's leak at the cylinder foot? Just wondering what to look for.
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  13. Disston

    Disston ShadeTreeExpert

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    You mean the large O-ring between the cylinder and the engine block? Fits around the cylinder spigot? It is really hard to pinch that particular O-ring I think.

    Write "valve cover gasket" 500 times on the black board. :deal
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  14. sh1bby69

    sh1bby69 Been here awhile

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    Yea the large O-Ring. It's leaking just above the push rod seals.
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  15. sh1bby69

    sh1bby69 Been here awhile

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    I've heard about doing that too. I'm gonna work on the bike tomorrow morning and see if the valve covers are warped.
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  16. Padmei

    Padmei enamoured

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    How can you pinch that O ring? Did you replace the orings for the top engine studs? Could it be from those leaking down & thru the bottom?
    Maybe you need the 2.2mm orings as I read somewhere the standard ones sometime leak???
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  17. bmwrench

    bmwrench Long timer

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    I probably should have been more specific. Apply the sealant to the cylinder head side of the gasket only. This address the warpage.
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  18. supershaft

    supershaft because I can

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    I have had good luck sandwiching the two gaskets with sealant and leaving the outer surfaces dry. If it works, you can almost pretend like it's a regular gasket.
    #18
  19. bmwrench

    bmwrench Long timer

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    Yeah, but who wants to lose .5mm of cornering clearance?:D
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  20. Disston

    Disston ShadeTreeExpert

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    You could grind down the edges of your valve covers to get back some of the clearance.
    #20