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Discussion Starter · #1 ·
Posted a couple weeks ago about a cracked head on a 680.

Pulled the three drain plugs and only the center (cracked head dome) dumped out green, either side, just a little oily fluid. The cylinders still have cross-hatching from the prev rebuild so I'm guessing it wasn't tool long before I bought the sled last year.

-Do you guys think I need to pull the cyls off and replace the base gaskets as well?
-What's the best way to drain some of the coolant making the least mess? (don't want all that's in the cylinder cases to drain into the bottom of the case)
-Anything else I should do while the top end is apart?

Thanks,
Jones.
 

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Considering what appears to be a recent rebuild, there is no need to replace the base gasket or do anything else that would require removing the jug. Actually, unless there was something wrong I wouldn't pull the jug off if it had 2000 miles on it.
 

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Discussion Starter · #3 ·
Thanks to BigWedgies for the cylinder head!
 

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Definitely pull the center cylinder at the very least and replace the base gasket, or it more than likely will happen again right away. That is more than likely the cause of the problem. The coolant didn't get into the cylinder because the head cracked, the head cracked from the coolant in the cylinder. The aftermarket paper base gaskets are known for not holding up on the ultra engines and will turn to mush and let the cylinder fill with antifreeze which then tries to hydrolock the engine but sometimes will instead crack the head. Check for broken studs on that cylinder also. If it were me, i would check the gasket on that cylinder. If it is black paper aftermarket, i would pull all three and put new ones on. The best ones that will hold up are the factory polaris ones which are pricey at $26.36 each, or you can order some from cometic that are rubber coated aluminum. They are their AFM series and are .018 thick. Last time i ordered some they were around $9.00 each. You can also order the afm gaskets from Doug Flannery since that's all he uses on ultras and xcr's because the paper ones are junk.
 
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