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'99 Grand 3.3L head gaskets

1239 Views 2 Replies 3 Participants Last post by  Doug D
I'm an original owner of a '99 Grand Sport with 3.3 and 170K. The tranny is running fine but the engine may be done. I'm hoping to get a few more miles by swapping the heads with a pair from the junk yard off a 2000 3.3. The rear head is not getting sufficient oil and the front head on the far right is close to dry. The plan, or Hail Mary pass is to unclog the oil galleys with the heads off and hope for the best. A few questions: Should I use gasket sealant for the head gaskets? Do any intake or head bolts require thread locker?

Any suggestions on how best to clean the head and block surfaces are welcome. I've yet to find a sticky on any site with a DIY guide on head replacement. Any tips are much appreciated!
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· Registered
6,110 Posts
Never, never, ever use any type of sealant on head gaskets. On the valve cover gaskets, it's okay, but not for the heads. You'll create more problems than you already have. What type of oil are you using and how often have you been changing it along with the filter? I have a 99 GC with 196,000 miles on it and it runs like a top. I use Castrol 10w-30 High Mileage motor oil and a Purolator Gold filter and change it every 6,000 miles. Something doesn't sound right to me. Perhaps you could try an engine flush or two along with oil changes and clear the galleries that way. The 3.3 is pretty much a bullet proof engine.

· Virginia Gentleman
8,736 Posts
Regarding the head bolts. If you do have to replace the HG, I believe the head bolts are stretch-to-yield bolts. There is a set of torque requirements where the bolts are torqued down to s specific value in succession with the final torque a 1/4 turn. You'll definitely need a torque wrench for this and NEW head bolts.

And no, you don't generally use a sealant for the head gasket. A good gasket and using the proper torque values should be sufficient. And don't forget to have the heads checked for straightness - they'll probably need to go to a machine shop.

But before replacing the heads, I'd check to see why they are not getting enough oil. No sense in putting "new" heads on if the real problem hasn't been fixed.
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