I have just received a 95 lumina from my sister-in-law. I had repaired her ignition problem once before by soldering her extra key to the wires under the dash because it wouldn't start due to the resistance not working at the ignition. It has run fine since but now it is having problems with a lower headgasket. She is getting a lot of coolant in the oil and it is now sitting in my driveway waiting to be signed over to me. I am wondering One; is changing the head gasket a huge job, and two; I am very mechanically inclined but have never really gone to the depth I am assuming it will take to change them. There is a slight knocking in the engine, but it comes and goes. The car ran fine before it was parked just a week ago, and I know that knocking can mean some really serious issues, but if there is anyone who can help me I would sure appreciate it.