The Ford-sponsored VH Sludge Test being developed for the upcoming passenger car engine oil category ILSAC GF-6 is greatly needed, but it is running out of test hardware. The VH Sludge Test is replacing a test that has been around since the 1990s, and for the past five years, the labs have been using vintage 1994 engine parts since they are no longer being manufactured. The joint Auto-Oil Advisory Panel (AOAP)/Passenger Car Engine Oil Classification Panel (PCEOP) meeting held on 14 May in Trenton, Mich., U.S.A. heard an update on the test.
The challenge has been to get the Sequence VH to be as severe as its predecessor, the Sequence VG. According to Ron Romano of Ford, the test developers tried running the test for more hours to see if that would increase test severity. However, increasing the test time to 240 hours incurred absolutely no increase in the sludge. He also said that their fuel formulator is currently mixing a small batch of more severe fuel, which should be available in about two weeks.
The test developers are investigating procedural changes and operating differences in hopes of finding a source for this lack of severity. The Powertrain Control Model (PCM) used for the VH is theoretically calibrated the same way as the PCMs used in the earlier VH tests and similar to the VG calibration. However, the new engines are behaving differently and the test is running mild despite of this.
There may be some undiscovered calibration differences with the PCM, but whatever these differences are, the test developers will have to adapt because the old PCM is no longer available. Because of all the unknowns causing the severity shift, the test is basically back to step one.