somethin strange happend after i parked n turned off my car today...got a 01 integ...b20 engine... after i shut off the engine....heard a hissing noise...popped the hood open n noticed that steam was going into my reservior tank from the radiator...it was so hot it was boiling the coolant in the tank...WHY is that?? this is a first for me...

 

Try replacing your radiator cap.

 

Did you notice your temp gauge? You should never be boiling over your overflow tank unless your cars not being adequately cooled. I'd suspect your fan or your fan relay as the culprit. You might even be low on coolant. You could also have a bad radiator cap like ruffrhyder posted. Don't cheap out on a rad cap, I'd definitely go with a Honda OEM one.

 

With a proper coolant level and a leak free system, a malfunctioning fan shouldn't push you to the point of boiling in the overflow tank. It's more likely there is a leak somewhere...potentially the radiator cap, but don't stop looking there.

 

^I actually noticed that with my 92 DA my fan wouldnt' turn on, and it was staying nice and cool. That's a good point. I just got into the whole import scene. With my Caprice my fan clutch went out and it would overheat real quick. These Hondas love to stay cool I guess.