What it Does
Oil changes fulfill the same function for these GDI (gasoline direct injection) engines as they do for other “normal” gasoline and diesel engines. Used oil gets drained and does so (hopefully) per a healthy interval that yields good value (service life relative to cost, and good engine protection throughout) and gets that oil out before it experiences significant changes in lubricity and additive protection. Oil filters get changed because they have a finite amount of capacity to store debris that gets removed from the engine oil, and if they are run for too long, excessive debris storage can result in the filter going into bypass.
Why This Matters
GDI engines need oil changes for the same reasons that other engines do, but they can actually degrade the oil’s performance more rapidly. This is relevant to both oil selection and proper change intervals. Also relevant to oil selection is the concern of LSPI (low speed pre-ignition). This condition commonly occurs in GDI engines and can be prevented or discouraged by running engine oil that resists LSPI activity. Unfortunately, while GDI (gasoline direction injection) represents an advance in technology, it’s an advance that the North American oil market has not fully caught up with.
Possible Problems
Soot Production:
Soot production is a normal characteristic of GDI engine operation. The problem that can occur here is that soot production suspends hard particles in the engine oil. These particles have been associated with timing chain wear. Two of the most important ways to counter this are to change the oil before soot production has the chance to encourage chain wear, and to run (if possible) oil of the ideal dynamic viscosity (this goes beyond simply selecting oil based on the viscosity printed on the bottle.)
Timing Chain Wear
GDI engines with poor oil change history (or less than ideal oil change history) risk premature timing chain wear (please see “Soot Production” above.. Timing chain replacement is a major repair operation. The cost to do it well is certainly far from engine rebuild or replacement territory but also substantial enough that you want to keep that timing chain setup healthy for as long as you possibly can. Time will tell with GDI engines, but previous (older technology) fuel injected engines have commonly seen chains last for 200,000 miles and much longer still!
Lacking Oil Selection
- The North American oil market has not fully caught up with GDI engine technology. Soot production can be discouraged by running oil with sufficient dynamic viscosity, but this concept is not commonly discussed in or among repair facilities, and dynamic viscosity is not addressed or disclosed by the normal viscosity rating shown on the bottle. Options here are limited to non-existent. Soot production can also be resisted (we think) by running a long-life rated oil, but options here are extremely limited. The ACEA A5/B5 rating can be found in Pennzoil’s 5w30 Platinum line but can be difficult or impossible to find in 0w20 and 5w20 oils. Running 5w30 A5/B5 oil in a GDI engine spec’d for 5w20 or 0w20 may benefit the longevity of the timing chain but sacrifice lubrication quality in the cylinders.
- Relevant questions here are “What gets you through your powertrain warranty?” and “How long do you want your vehicle to last?” Many (perhaps most) GDI engines will get through the powertrain warranty without any special attention to oil selection, especially if the oil is changed at reasonable intervals. However, if you’d like to run your vehicle to 200, 250k, 300k, or even further, you are going MUCH farther than a 60k or 100k powertrain warranty takes you, and this makes proper oil selection even more important.
Improper Change Interval
An easy way to think about this is that GDI engines “beat up” on the oil more quickly than the “normal” fuel injected engines that have been around for 20 years now. Maintenance schedules don’t always reflect this and may show the same minimum and maximum intervals for both engine types. So (for example), for a “normal” gasoline engine and a GDI engine being run under similar conditions, if 5,000 miles is a appropriate interval for the “normal” engine, we might advocate 4,000 miles for the GDI engine. This goes back to the concern of warranty period versus desired vehicle lifespan. The vehicle probably won’t need much extra help to get through the warranty, but if you want that engine to last for a 300k life cycle, careful oil change interval selection might help you!
LSPI
LSPI refers to low speed pre-ignition. This is a condition in which uncontrolled combustion occurs in the engine’s cylinders or combustion chambers. Uncontrolled combustion refers to a condition in which out of control combustion events take place (at the wrong time, wrong location in the cylinder, or both). Severe uncontrolled combustion can cause internal damage (Further details available in separate entry.) There are engine oils available that discourage this activity from taking place.
Long Story Short
GDI engines are harder on the engine oil than the preceding fuel-injected engines that have been around for the last 20 years or so. Extra attention to oil selection, a little bit more money for high-grade oils, and moderate reductions in common change intervals can help you save money over the long run.
Recommended Parts Brands
A5/B5, API SP, and LSPI protection are relevant things to look for in oil selection.