Northstar Engines and System Technical Discussion Discussion, For you guys who have done a headgasket job on the 4.6 in Cadillac Engine Technical Discussion; Guys, I have a few questions concerning a headgasket job on a 99 sts with a 4.6 northstar.
1. Should ...
For you guys who have done a headgasket job on the 4.6
Guys, I have a few questions concerning a headgasket job on a 99 sts with a 4.6 northstar.
1. Should the heads be milled down and the block be decked or is this a waste of time. Also I assume the cams would have to be removed for the machine shop to complete the job, correct?
2. I removed the rear head today and looked at the head gasket but did not notice anything really bad...Should there not be some clear reason for the antifreeze to get into the cylinders?
3. When I pulled the head bolts out it pulled some of the threads out with it. Is this a sign that they needed to be replaced?
4. What is the difference between the "Bigsert kit" and the regular one??
Re: For you guys who have done a headgasket job on the 4.6
1. Most heads don't need machining. Did mine without and no problems. Use a straight edge and feeler gauge to check for flatness. Yes, if you had the heads machined you would have to remove the camshafts.
2. Examine your gasket carefully to find the leak passage from the water jacket to the cylinder. The piston with the leaky gasket around it will be clean while the others will have some carbon buildup.
3. This is why you need to Timesert your block when you remove the heads.
4. Bigsert is an oversized Timesert for blocks that have already had Timeserts installed. If you are on the first headgasket job on your Nstar you will need the regular timeserts.