These three needs are no different than those ILSAC laid out in 2001 for the current GF-4 category, nor those identified for GF-3 in the mid-1990s by a committee of auto, oil and additive manufacturers. But ILSAC also unveiled a list of 22 specific performance issues that it wants GF-5 to tackle, ranging from corrosion to black sludge to elastomeric compatibility.

In a Dec. 3 letter to the joint ILSAC/Oil Committee that will develop the new specification, ILSAC Chairman Mike McMillan of General Motors stressed that GF-5 must provide backward compatibility to service older engines and should include turbocharged, supercharged, and spark-ignited, direct fuel-injected (SIDI) engines. Diesel engines are excluded.

The specific mention of turbocharged, supercharged and SIDI engines is new for ILSAC. None of these technologies were singled out in earlier GF upgrades.

McMillan also pointed out that several new engine tests will be needed for GF-5, either because of hardware availability issues, or because the significance of the test in evaluating oil performance is now or will be in question during the GF-5 lifetime, 2009 to 2014.

It is imperative that work on replacements for these tests be started soon so they will be ready in 2008, he emphasized.

Among the critical tests needing scrutiny, he said, are the Sequence IIIG which measures valve train wear, viscosity increase and high-temperature, piston-skirt deposit formation; the IVA (valve train wear); the VG (wear, sludge and varnish); and the VIB (engine oil effects on fuel economy).

While the life of some of these tests could possibly be extended past 2009, McMillan noted, it is extremely doubtful that any of them would continue to be available in 2014 – ten years from now.

Another highlighted engine test was the Sequence VIII, formerly called the L-38, based on a custom-made single-cylinder engine; it measures copper/lead bearing protection and has been in service for decades. It will need to be retained or replaced by a bench corrosion test, McMillan suggested.

McMillans letter, which was addressed to ILSAC/Oil Chairman Bob Olree, said nothing about the phosphorus content of GF-5 engine oils, but that issue will likely be a source of contention, as in previous upgrades. Phosphorus is a well-understood, inexpensive and particularly effective antiwear additive, but it has known catalyst-poisoning properties which automakers say can damage their emission systems. A satisfactory engine sequence test to measure this poisoning effect has not been found, however, leading ILSAC to restrict the phosphorus content of engine oils. The phosphorus level has steadily been reduced, from 0.12 percent in GF-1 to 0.10 percent for GF-2 and GF-3. For GF-4, auto manufacturers initially wanted phosphorus cut to 0.05 percent but settled on 0.08 percent.

In the absence of an engine sequence test for catalyst compatibility, phosphorus limits are again anticipated for GF-5, but a new test for phosphorus volatility will also be weighed, Olree told Lube Report.

Olree, also of GM, has said his company is considering developing a Sequence IIIH replacement for the IIIG test, using its Twin 16-valve Ecotech engine to measure viscosity increase and piston deposits. Ford noted that it is considering extending the life of the Sequence VG.

Here is ILSACs list of specific GF-5 needs, the performance parameters involved, and the suggested test for each:

Possible Tests for ILSAC GF-5