Disclaimer: The CarCynic is an AMSOIL Dealer. AMSOIL is a Line of Premium Synthetic and Synthetic Blend Motor Oils.
Car Dealers — Both Large Dealerships associated with the Major Manufactures, and smaller “By Here – Pay Here” used car dealers are violating Manufacture’s Recommendations, and potentially causing future damage.
Most Performance Sedans, as well as lots of other vehicles with new technology or high-output engines, require Full Synthetic Oil. Close Manufacturing Tolerances, High Temperatures, High Compression Ratios, and the materials used in newer engines, demand the performance of synthetic oil — fully synthetic oil. The conventional oils found in Synthetic Blends, Part Synthetic, or “ParaSynthetics” won’t cut it for some of these newer or high performance engines.
However, Dealers — Again, both the dozen-acre dealerships with the polished floors, free lattes, and spotless service bays, as well as the mom and pop place with the roaches crawling on the paperwork as you try to sign it — typically stock a few different weights commonly used in modern cars, and they frequently op for “Synthetic Blend” motor oils in an effort to cover the requirements of as may types of cars a possible with as few types of oil as possible.
They drain the oil whenever they acquire a new (to them) car. This part has both legitimate and deceitful aspects to it. When a dealer takes a trade, or buys a car at auction, they may not know when the oil was last changed, or how meticulous the last owner was. The dealer legitimately and honestly wants the car to be ready for it’s new owner.
Dealers also know that buyers will often pull out the dipstick and look at (and sometimes smell) the oil. Even customers that don’t really know how to “read” the oil don’t want to see dark, old oil in a car they are considering dropping thousands of dollars on. However, changing the oil can also hide serious problems such as a blown head gasket or worse.
No matter the dealers’ intent, changing the oil, but not stocking 52 different types of oil is what makes sense for car dealers.
The result? That performance sedan that you just haggled a really good price on now has a “Synthetic Blend” in the engine when the owners’ manual clearly states that Full Synthetic oil is required.
No — Manufactures don’t just make this stuff up to impress buyers, or to make you spend more at the dealer’s service department. Things like turbochargers, nylon timing chain tensioners, and modern materials and machining techniques really do need Fully Synthetic oil if that’s what the owner’s manual states.
So now you blast off the lot in your performance sedan. You go on a long highway trip. You blast the AC and the premium audio system as you sit in stop-and-go summer traffic. You’re feeling good! But inside your engine, increased wear is occurring. The conventional petroleum components of that Part Synthetic oil are coking in the turbo. Breakdown products of the blended oil are becoming lodged in the tiny solenoids that operate the Variable Valve Timing. That modern 2.0L engine, which does more work than a 1970’s 5.7L V8, is potentially experiencing instances of metal to metal contact. (Note also that as the linked article states, modern cars with “Start/Stop” are also more subject to instances of metal to metal contact. Look for the following symbol on your dash or center console.)
So should we sit around hoping that all used car dealers suddenly become philanthropic organizations and put charity over profit? — Probably not going to happen. If you buy a used performance sedan, and the owners’ manual calls for a Full Synthetic oil — unless you know that the dealer did an oil change with the correct product — change the oil as soon as possible after you purchase the vehicle. Change the oil yourself, or make sure you know what the shop is putting in the car, and that it meets or exceeds the manufacture’s specifications.
Note: Yes, of Course the CarCynic Recommends the proper AMSOIL full synthetic oil for performance sedans, but this article isn’t about AMSOIL. It is about Synthetic Blends of any brand being used in vehicles that specify a full synthetic.
Note: The situation described actually happened with the vehicle pictured at the top of this article. The oil was changed to Full Synthetic AMSOIL 0W-20 within days of purchase and before driving any significant distance.
