BG RF-7, however, is formulated to correct a problem within an engine. In older engines, where ring land sealing is poor or cylinder wall areas are worn, BG RF-7 helps build up the viscosity character of the engine oil under hot conditions so it doesn’t thin out and seep past the rings. BG RF-7 forms a cushion that reduces oil loss, increases or holds compression, and protects the cylinder wall from further wear. BG RF-7 also contains a seal conditioner to keep seals soft and pliable. Its primary purpose is to increase and improve the way the oil functions under high heat so it does not thin out.