I am completely at wits end with this stupid F**KING LEAK! 3rd O-ring and there are 2 slightly pinched spots and the second the coolant level gets to the thermostat housing it leaks as if there was a crack problem is there is no crack and I took the top of the housing off i see no sharp edges, i took the f**ckin tube off again and felt all around and felt NOTHING sharp and I have lubed the damn thing with white grease so its not a lubrication problem is there a special way this O-ring should be in the slotted area? i have tried it at the top one pinched EXACTLY where the leak is, the second one got cut in half RIGHT where it leaks... this one the 3rd one got 2 little pinch marks and leaked just like the other 2... im probably gonna forget about the truck and just let it sit for awhile til i can relax this is ridiculous to say the least.
The picture doesn't show it well but where the original O-ring goes there is a mark that shows that the original O-ring wasn't seated flush with the top but rather at a diagonal way.