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Thread: 6.5 Precup cracks

  1. #1
    Join Date
    May 2008
    Location
    Saskatoon, Sk
    Posts
    20

    Default 6.5 Precup cracks

    I am currently doing the head gaskets on my 94 6.5 non turbo. All looks good but all eight of the precups have cracks. None of the cracks are into the fire ring yet, but some are coming close. I have read in other posts that there should not be a problem with using these as long as the cracks are not into the fire ring or there are no pieces missing. How long will these precups likely last? I would hate to put this all together and have to do it again in six months. I've never messed with a set of precups before, are these easily changed and readily available?
    1994 Chev 1500, 4x4, 6.5NA, 180,000 miles
    Stock....... for now
    1991 GMC 2500, 2wd, 6.2, 350,000 (30k on engine)
    Soon to be a parts donor
    1993 GMC 2500, 4x4, 6.5T, 225,000 miles. A work in progress

  2. #2
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,576

    Arrow

    The cracks are common and normal. They could have designed out the cracks, but they didn't. If you have significant miles on the precups, don't worry. The cracks happen early in their life, and they continue to be fine for a long time with no problem. If they are high milers and the cracks haven't crossed the fire ring, the likelihood they will is very slim. Even so, failure from this is more rare. I've seen one case, but it was likely due to an extreme overheat anyway.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  3. #3
    Join Date
    Apr 2004
    Location
    portland or
    Posts
    212

    Default

    im in the same boat, make sure you take a good look in between your valves, jim recommended a great repair if you have cracks there. i just did it and it only cost me 20$ to fix my cracked heads. take a look at my post on cracked heads. good luck rob
    94 6.5l turbo engine code f
    homemade fsd/pmd cooler
    k&n air filter
    many goodies coming soon,oil cooler lines and 3.5" exhaust
    lots of 67-69 camaros

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