AT least the new G5 standard will be attempting to address the issues I have stated above.
he Sequence VG is a fired engine test designed to evaluate the candidate oil's ability to prevent sludge and varnish deposits in short trip low temperature operation.
The test cycles between low and high temperature operation, simulating the short trip driving conditions which promote the generation of acids and fuel dilution in the crankcase. A special fuel is used which is prone to sludge and varnish generation.
The rated performance parameters for the Sequence VG are:
* Average Engine Sludge (AES)
* Rocker Arm Cover Sludge (RACS)
* Average Engine Varnish (AEV)
* Average Piston Skirt Varnish (APV)
* Oil Screen Clogging (Screen Clogging, %)
* Ring Sticking (RS)
Proposed Performance Limits for AES, RACS and Oil Screen Clogging will be more demanding for GF-5 compared to the limits for GF-4.
Sequence VG Test Conditions
This test alone acknowledges that sludge/varnish/deposits are an issue.
However...the point missed is that refining petro oil into something similar to group IV is going to make it cost just as much as group IV and more if oil prices continue rising.
I still don't see a severely Hydro-cracked Group III that equals or rivals a quality group IV true synthetic,especially with doing extended OCI's. Even when that day may come.......you will pay a premium price if you buy into it.