Discussion Starter · #1 ·
Every 2GR-FE I've ever opened - and I have opened a few - has substantial oil sludge deposits in the intake ports. These are caused by an over-agressive PCV system. It appears that the fuel wash in the intake ports is not able to clear the sludge. The effect of the oil on combustion in the cylinders is probably very small or negligible. However the long-term accumulation of sludge in the intake undoubtedly - indubitably, if you prefer - impairs the volumetric efficiency. From some engines, I have pulled mothball sized clumps of sludge out of the ports. This affects the Toyota 3.5-liter V6 found in Camry, Rav4, Avalon, Highlander, Sienna, Venza, and Lexus RX350.