I'm changing out my head gasket and I was wondering do I have to change out the pston rings as well? Reason why I ask is because my oil comes out looking black and watery. The coolant has oil in it Every three days I have to fill in a quart of oil again. Am I losing oil because of the blown head gasket?

 

did you do a leak down test? or compression test?

 

How many miles are on the engine? If it's quite a few then leave the piston rings, they'll be OK. If this is a new engine, the coolant in the combustion chamber probably will keep the rings from seating and they'll need replaced.

 

I did a compression check and it varys cyl 1:50-100, cyl 2:100-130 cyl 3:100-130
cyl 4:130. The engine was bought used and is a 99 LS. Should I change the rings then?

 

The first thing you have to do is determine where your losing compression. Try puting some oil in the cylinders and see if the compression results are the same. If they are the same the rings are probably in good condition,.