I have a 87 Accord Si.. There is a hole/crack on the top of the tank.. easy access.. how can i fix this with out replacing the tank?? i understand that its a plastic tank.

 

I'd get a new radiator. Is it original? 17 years ain't too shabby...

 

How big is this hole? Are we talking a hairline crack or a big chunk of missing plastic?

If it's a hairline fracture you can use some radiator stop-leak which is available at any auto parts store. If it's pretty big though I would replace the radiator. You can get an OEM equivalent for about 100 bucks.