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Discussion Starter · #1 ·
Hey guys great forum!Just wondering if there are any suggestions on a leaking cylinder head gasket on a 1997 500cc.It leaks coolant into the right side cylinder after a new gasket has been installed.I installed it according to a polaris service manual so i can be sure that it was orientated correctly.After torqueing the cylinder head bolts in three stages to 20ft lbs both cylinders were leaking coolant into the cylinders.So i went to 35 ft lbs way past what the polaris manual reccomended.One cylinder seamed to be sealed after i ran it for a bit.. ie no steam when i removed the spark plug from that side but steam on the other side.Any suggestions on head gasket installation would be great.
thanks.
troy.
 

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did the engine ever overheat? could have warped the head. not likely to warp the cylinders due to the thickness of the block. check the surface of the head and deck to see if there are any gouges that would cause the leaking as well. take a piece of 400 grit or less sandpaper and tape it to a sheet of glass or other perfectly flat surface. run the head back and forth, and in circular motions, to see if the head is warped. if you have a consistent patern of sanding, then you should be fine. helps to put some water on the paper too so it doesn't clog so quickly.
one thing i used to do was always start the engines after i rebuilt them to see if they ran. sucks to have to drain the coolant if there were any problems. what i'm trying to say is when you put the gasket back on, and torque the head on, run the engine for about 20 seconds at idle before you put coolant in. shut it off and retorque the head. the heat will cause everything to expand a little, and torqueing it when it's warm will give you a little more rotation on the nuts. when it cools, fill it up with coolant and give it a shot. this has helped me for problem sleds like yours. put a new gasket in everytime you take the head off. make sure the surfaces are perfectly clean, and dont put any kind of sealant on the gasket. pretty sure the torque spec on the head is 24-26 ft/lbs. let me know if this works. if you have any more questions, please ask. -Polaris Doc
 

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Discussion Starter · #3 ·
Thanks polaris doc.I found out (by doing exactly what you said) that at one end of the head there was no sanding marks in one small area.Turns out this spot is where the coolant was coming into the head.So i removed the jugs and took both pieces to a trusted machine shop that builds racing engines.They agreed that it needed milling to correct it.Thanks for the procedure to re-install the head it will be of great value.
Troy.
 

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one thing to look out for is by milling the head is gonna bump up your compression and may require you to run a higher octane fuel. just a little FYI
 

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Bobinwi is correct. make sure you tell them to take the absolute minimum off when they mill the head. Should only take a few thousandths to clean it up. Now i've had heads milled in the past and the cuts are not that smooth, so you may have to rework the head with the sandpaper technique that I told you about before. That way you wont have a leaky head from a rough mill job. Not a bad idea to do it just to check their work. Also, have them tell you how much they had to remove. if it was less than .010", you should be ok on the gas you use. it's always a good idea anyways to run at least 89 if not 91 octane in sleds all the time.
Good luck man. -Polaris Doc
 

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Polaris recommends 88 octane fuel in their service manual printed by them. 91 is a good idea in this case.
 
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