I'm not sure if I'm asking this in the right place but here it goes. I bought a 1988 Dodge Pick-Up 4X4 318 V8 in Feburary of this year. The odometer and the owner says it only had 77,XXX miles so I'm not sure because it only has a 5 digit odometer. It used about a quart and a half of oil between the time I bought it and the time I had the oil changed in June. I work at Walmart TLE so I took my truck there to get the OC. I told the guy I wanted Pennzoil 10W30 but they put Pennzoil 5W20 and so far in almost 7 weeks and less than 500 miles it's used 3 quarts of oil. There are no signs of a oil leak around the gasket, the oil filter, or the drain plug. Is it possible to burn 3 quarts of oil in less than 500 miles? Is anything to add such as Lucas to slow this problem? Is the 5W20 just too thin/