Originally Posted by
JDMKidBill
I had my bike checked out earlier this week, and the the guy said it's not a crack. He pointed out that it progressively became visible from the headtube part of the downtube to the bottom bracket. He said it could be a bad paint job, or it could be a seamed tube. All in all, it was concluded that my bike is in excellent mechanical condition, and that visible vertical mark should not be a problem.
On top of that, more good news. My PD-M540's came in Tuesday, and my pedaling continues to improve. I am one happy camper

I'm glad it was nothing. Good for you. Now slap those pedals on and ride that bike.