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1990 Indy cooling problem.

1990indy500

New Member
Messages
2
Age
60
Location
North east Alberta
Just bought a " fixed up" 1990 Indy 500. Took it out today. It was about 25 degree f or -2 c. Took it for a rip and 15 min in the antifreeze recovery tank was steaming out. Could it be my t-stat or my water pump be the problem? The water pump belt is good. Sled idles at about 2800 which I think is way too high. We have about 12 inches of snow so I don't think that's the issue. Any pointers would be appreciated. Thanks
 
Thanks guys. Here is an update. The Indy 500 I bought is really a 400 bored out to 503. I was told the head, which is a 400 was untouched. The previous owner told me that a custom head gasket had to be made to mate the 400 head to the overbored cylinders. I took the head off to find that the pto cylinder had antifreeze on it. The gasket had failed. I called a Polaris dealer in Edmonton called cycleworks for advice. The fellow there told me the head had to be modified to fit the overbored cylinders and then a regular 500 head gasket would work. Who's right? Another question would be if you bore out a 400 to 500 will the walls on a gasket be too thin and will they just keep failing. Let me know what you all think. Thanks
 
The most I've ever bored out a 400 was .110ths to put 650 pistons to make it a 440. That was over 20yrs ago. Just going of memory. Make sure someone didn't sleeve it and the sleeves are flush to the top of cylinders. Sometimes they sink down. If its a 500 bore match a 500 head gasket up to cylinders to see how it fits. I'm pretty sure the 400 and 500 have the same bolt pattern. Matching the head gasket up will tell you. Then you can put a 500 head on it. This is just of memory pretty sure it's more than 25yrs ago we did this.
 


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