Possible coolant tank leak - or can something else cause it?

[dghii]

Bet its your tank.

Dry out the trunk and throw some talcum power under the tank. I really could see the crack in my tank until it was removed. It was hairline at best but once under pressure, it doesn't take much.

[patssle]

Originally Posted by dghii

It was hairline at best but once under pressure, it doesn't take much.

But the thing is after I dried it all out I started the car again and went for another drive - it didn't leak. It's not consistent!

[Gelbster]

IF - you have a hairline crack -it may take 1/2hr of running at normal temperature to build up pressure to cause noticeable leakage.
Remove carpet and use newspaper for leak detection?
Is the cap the old part number(that does not seal correctly after a while)?