07/22/2026
This pertains to GDI V6 GM 3.6L and also explains proper crankcase evacuation as well: 5w30 would be perfect if not for the excessive raw fuel pushed past the rungs compared to the old reliable port injection engines these replaced. So that dilutes the viscosity gradually right from the start. If you change oil every 3-4k miles you can also prevent the premature failures follow that regime. So as much as a quart in app. 1,000 miles in some cases really works against the 5w30 as in viscosity reduction. A 5w50 will give the cold start thinness (which in reality is already less with the dilution) when cold, and at operating temp when it won’t be at 50 either. It is not anywhere near exact to be more accurate as some drive long distances at steady interstate speeds, and the factory PCV system is operating properly and removing a good deal already. We find the majority of owners with miles like yours on an original engine, and original timing chain (don’t think I have seen any go 250k miles before) I would change the timing set including phaser gears to avoid a failure. So I assume you changed oil early as a rule and drive a good distance often at highway speeds where the stock system removes most by the intake manifold vacuum. It’s only present at idle, light cruise, and deceleration. Any time the throttle is opening the usable vacuum drops and cannot maintain the proper flow through flush and evacuation a true full time evacuation system and most catch can designs do not trap the majority of the oil contained in the crankcase vapors. That is also critical because you only want air and fuel present in the combustion chamber. So let’s imagine there is a room. That room is crankcase in this example. And there is a vent in the floor spewing smoke into the room (blow by) and the goal is to clear the room as completely and quickly. Like a firefighter evacuate smoke after the fire is out. There are two windows in the room. If you open one window, you solve part of it by relieving excess pressuring built, but the room remains filled with smoke. Open the opposite window, and place a fan in it, sucking out, the room quickly clears and remains clear. That is what a true crankcase evacuation system does. And our patented system is the only one curing the market that provides full time vacuum, even when the throttle opens to accelerate. And includes the most effective air/oil separator removing up to 95% of the oil and most other contaminants from the vapors being ingested. So it’s the only one we are aware of that emulates most of the vacuum pump systems. The only one that fills the huge gap between a catch can, and a full on belt driven system. So using the two together, is where we see the best solution. A 5w40 will also help if Leary of the 5w50.
