Need some help before I put out the $$ to get it diagnosed and repaired. I have a 2000 Sierra w/ 5.3L v8. I now have 222K miles on it. Used Mobil 1 (regular) oil for the 1st 12K miles and then Mobil 1 synthetic ever since.
Since 207K miles, I've noticed the oil is being used up/burned etc. Upwards of 4 quarts b/w oil changes. There are no drips on the driveway, no smoking out the exhaust. Is this an intake manifold issue or a cracked head? I'm assuming the oil is going into the antifreeze?
I'd appreciate some input.
Thanks!