hello all. my first post here, so I'm not sure if it's the right forum.  :-)

I have a 99 TJ with only 70,600 miles on it.

I had to replace the headers awhile ago since they, of course, cracked. While putting on the new headers, the mechanics found a crack in the block. It is located in the water jacket. There was a little coolant leaking, but not much.

I tried getting Chrysler to be big about things and replace the engine for me, since it seems to be a flaw in the casting of the iron, but no go. They laughed.

so I stuck some AlumiSeal in it and the engine survived the summer and is still going strong here heading into the cold season, and is not leaking coolant.

Do you think I'm pretty much good to go, or is it just a matter of time before it craps out? I've been driving it like this for quite awhile now, and wheeling once a week, and no issues at all (other than the lifters or whatever are somewhat noisy when I accelerate, but maybe all Jeeps do that).

and if it does, where do I get a new engine, other than the dealer?

That noise may not be lifters. It may be an exhaust leak.  It's also possible your timing chain is bad.  I've had both problems, and they both sounded like lifters.  

I think you will be fine as long as you keep an eye on it.  If it has lasted this long, it is problubly ok.  And if it does it again just re-seal it.  But if it gets worse, NAPA has 4.0 long blocks for about 1400$

look to the local jeep clubs for a used engine.  i picked one up for $700 cdn.  and sold the computer for $270.

you've got time to find a good deal.

my 2 cents.

Pete

check in the back of JP  golden makes a  as advertised  260hp stroker for about 3 grand. other than that check auto trader etc for wrecked wranglers maby cherokees etc being parted out or as whole snag teh engin sell the good stuff and let the scrapyard give you 50 or 60 bucks for the rest.