This product may help reduce the amount of oil your suburban is burning. It is called Restore Engine Restorer and Lubricant. It's available where auto parts are sold. or here:
https://www.amazon.com/Restore-8-Cylinder-Formula-Restorer-Lubricant/dp/B000AM8BCC
I used it on several cars & trucks and it works great. I had a 1977 Honda Civic with nearly 100,000 miles it would burn a quart of oil with every tank of gas. Once I put in the Restore and drove the 500 miles for it to take effect, the oil burning dropped to one quart every 3 months.