Chores like raking leaves and cleaning the garage are easy to ignore weekend after weekend, but when it comes to maintaining your 4x4 a reluctance to get the job done can have catastrophic effects. Jobs such as changing the engine oil and transmission fluid are ever-important steps in keeping your 4x4 in excellent running condition and are often overlooked or delegated to the quickie-lube station that may use inferior products. Use of inferior products can extend beyond the quickie-lube station as well. It's pretty easy to be tempted by whatever oil is on sale at the auto parts store, but be aware you typically get what you pay for and your engine will reflect the purchase.
With nearly 160,000 miles on the 4.0L I-6 in our Cherokee, we wanted motor oil able to withstand fairly severe conditions. We even considered switching to a high-mileage motor oil, which is usually offered in higher viscosity and includes special additives to slow oil burn-off. Instead, we decided to reach all the way to the top shelf and fill the engine with the new, full-synthetic Pennzoil Platinum, which is said to offer superior antiwear protection and consistent engine performance.
Pennzoil Platinum is a full-synthetic motor oil available in 5W-20, 5W-30, 10W-30, 5W-40 Euro, and 5W-30 Euro. We chose the higher-viscosity 10W-30 to address our high-mileage needs, but newer, lower-mileage vehicles can get away with the 5W-30. 5W-30 is also advised in colder climes since it will flow better in colder temperatures. If you're unsure what oil viscosity to use in your vehicle, you should first check with the vehicle's manufacturer to see what it recommends. In any case, 10W-30 is pretty darn close to a one-size-fits-all oil, so it should suffice in most engines.
A lot of inexpensive conventional oils won't hold up as well as top-shelf full-synthetic mixtures. Full-synthetic motor oil generally offers a number of advantages over conventional oils. For one, it flows through the engine more smoothly while keeping it cleaner at the same time. With so many natural impurities such as reactive hydrocarbons and sulfur in conventional oil, it usually requires more frequent oil changes to maintain a properly running engine. Synthetic oil is also better at preventing engine wear because it maintains its viscosity longer, which also helps extend oil-change intervals.
Along with the full-synthetic Pennzoil Platinum, we also picked up some Pennzoil Multi-Vehicle ATF. The ATF is a synthetic blend with excellent high-temperature oxidation protection, and it features an advanced additive system for automatic and powershift transmissions. Since we'd be draining both the oil and transmission fluid, we also obtained new fluid filters and pan seals from Fram and Summit Racing.