Vehicles with over 70,000 miles are considered high-mileage vehicles. These cars and trucks require special oils to help keep their engines running smoothly. Motor oils that are specially designed for high-mileage vehicles help to prevent and reduce leaks and reduce compression loss, common in older vehicles. Some motor oils perform better than others in regards to the protections they provide.
Full Synthetic Oils
According to Bestcovery, which researches and rates consumer products, the most efficient synthetic oil on the market for high-mileage vehicles is Pennzoil Platinum Full Synthetic. Bestcovery gave the oil a 5-star rating based on performance and engine protection, and it is consistently ranked as a top performer. According to the article, while prices vary, typical costs for a 5-liter jug averaged £13 as of September 2010.
Partially Senthetic Oils
According to Web Racing, the best partially synthetic oil on the market is that made and distributed through Brad Penn. Partially synthetic oils are designed to improve lubrication and performance in high-mileage vehicles. According to Web Racing, Brad Penn partially synthetic oil is often used in high-performance vehicles, such as race cars. It should be noted, however, that Brad Penn oil is specially designed with a blend of zinc and phosphorus and should not be used on vehicles that utilise catalytic converters due to the risk of damage to the converter. According to the website, typical costs for Brad Penn partially synthetic oils average £3.50 a bottle.
High-mileage diesel engines require the use of a special oil. According to Mobil Oil's website, a heavy grade 5W-40 oil is best for use in vehicles that hold a diesel motor with high mileage. The use of heavy grade 5W-40 oils help to extend the life of diesel engines by protecting the engine against leaks, particularly with engines that contain diesel particulate filters (DPFs) and diesel oxidation catalysts (DOC's). According to the report, 5W-40 oils also improve engine function in diesels that contain exhaust gas recirculation (EGR) and after-treatment systems.