Hi Bruce and all,
In reply to your info I have checked off your questions as follows:
Oil level is good - no light, Oil changed about 1 to 1-1/2 mos. ago by same person that told me engine needed to be rebuilt. Engine runs like a top. No lifter noise. Never has been (only noise is exhaust system that needs to be replaced). Coolant temp is normal. Same as always. I have always changed oil every 3000 miles but that takes me sometimes 4-6 mos. to put on 3000 miles. Then oil level low light comes on before 3000 miles. I usually add a quart and can then run for another few weeks before changing.
I am taking it to Cadillac (the same dealer that has worked on my car for 20 years and has, I believe, been very honest with me.) I only started taking it to local guy for oil changes the last oil change. I also want to state that this person stated to me "I don't usually rebuild engines, but I will do it for you". This sent off some red flags for me and my son. I am 77 years old and cannot do any of this work myself. I am somewhat car repair knowledgeable but the NS engine is not the usual engine. Where is a honest mechanic when you need one??????