I had a freeze plug leak on my driver side under the motor mount. At first I thought it was leaking from the head gasket, so I bought a head gasket and proceeded to change the old one out. Upon completion of the head gasket installation, I poured coolant in and it was still leaking. I reassessed the situation and localized the leak to be coming from behind the motor mount on the driver side. I then pulled the engine out replaced the freeze plug and put the engine back in. I filled it up with coolant, tranny fluid, and changed the oil and filter, and NO LEAKS! YAY! When I went to start it, it turned over and coughed a little, but no start. I called a friend to see if he had any suggestions, he offered that the timing was off. He was right. So, I rotated the crank pulley to TDC and aligned the rotor button with the #1 spark plug and tried again. This time it sounded like it was going to crank but then the cranking slowed down and the starter just clicked a lot. I figured the battery was dead so I tried jumping it, with the same outcome just a bunch of clicking. One thing I think it might be is, when I was disconnecting the transmission range sensor connector it was really hard to get out and really hard to get back in and it is not fully seated, it is about 1/8 of an inch away from being seated. Also, when I was dropping the exhaust system I broke one of the O2 sensor connectors, I don't think this would keep the engine from turning over, but I'm no expert.