I just replaced mine at 77k. I was walking away after I pulled in at work, and as I walked around the front of my car without thinking twice I stepped over a puddle of coolant. Took a few more steps and thought what the ****? Turned around and my car was taking a leak. I looked under the hood and couldn't find the leak, so I turned on the car and came around front and the seams on the top of the radiator were spewing like sprinklers at 2:00 in the morning at Dodger Stadium. What a mess!!! No warning at all, just happened. Got it fixed for 3bills at Goodyear, I don't mess w/fluids.