Water pump on 1999 summit 600

[highmark x]

Have a 1999 summit 600 and the motor blew again this winter, 20 kms after doo dealer rebuilt engine last march. Decided to do it myself and found out that they put oversized piston on the one side and didn't hon or bore the cylinders. Got that all done and sled would overheat after 2 minutes driving. All the air was bled out of the cooling system so checked thermostate and it worked fine, next checked water pump and found a bearing needle jammed into the propeller of the water pump and it stripped the nylon gear. Got new water-oil pump assembly and took it out for a ride. After 75 kms the sled overheated again. Felt tunnel and it was ice cold, no circulation again. Anybody have any ideas as to what could be causing that nylon gear to strip again, since we checked for any other bearing needles in the crank.???

 

[tko sled ed]

I don't have any real good ideas but my 97 would over heat checked the t-stat it seemed to work fine but replaced it any way. I haven't had a problem since.