Might not keep the car forever. 1987 Audi Coupe GT I-5 2.2. It has 180k, but the engine is relatively clean. Wondering if I can do a full treatment, (clean+rinse) then go for a small maintenance dose with an extended drain? Sound ok? Seals are not bad, just wet and car burns less oil than ANY other car I service, 1q/4000-5000 miles.