I had to repair the threads on the cooler of the 116 I sold not too long ago. Just make sure that you drill straight and not into an angle so the replacement fitting will fit flush. The worst part is cleaning out the metal shavings after the work is complete. Do the cleaning after the drilling and tapping but before finally threading in the new fitting. Good luck and I hope this applies to the 603 cooler as well. I wouldn't know as my cooler was bypassed by the PO, like 6 years ago. Still alive and kicking!

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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