Quote:
Originally Posted by Elite Engineering
What GM won't tell you is the reason for the bypass valve. ALL GDI engines experience many times the abrasive particulate matter shed from intake valves and contaminating the engine oil. The filters may clog to the point of restricting oil flow and turned bearings are the result. And this is not just the GM GDI engines, it is ALL GDI engines as this is an inherent problem along with the fuel dilution issues.
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I know this particular post is over a year old, but it needs to be rebutted.
All oil filters I know of come with a bypass valve, not just those for DI engines. For example, the filters for LS engines (which are not direct-injected) have them. The difference for the LT1/4 engines is just that they stay closed until they reach a higher pressure of 22lbs, vs 12psi for the LS3 filter (again as just one example).
Also, while it's true that carbon buildup on intake valves is an issue with DI engines, I don't see how it could end up in the oil. The valves don't have exposure to the oil (hopefully!). Besides, the whole point of the problem is that the carbon never gets washed off the valves in a DI engine because there is no gasoline going past the valve to act as a constant solvent. The amount of carbon deposited on the valves is the same as non-DI engines, but
less of it is shed from the valve, not more.
GM is clear on the reason for the change in bypass pressure: the tighter clearances in the newer engines requires a filter that is less easily bypassed so that the oil is better filtered. I don't see any mystery here.