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Originally Posted by KillerBMotorsport
Agreed.
The other thing no one knows, is if this RTV shedding is only temporary from loose bits at initial startup/break-in, or if the RTV deteriorates and breaks down over time, and is ongoing to some (hopefully lesser) extent.
Talked to a lot of BRZ/GR guys at Boxerfest this weekend and a few of them of them had dropped their pan and inspected the pickups, with no silicone inside. So that was good to hear.
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Nice to hear about the responses of people who have not seen any RTV trapped within the pickup filter. Most likely what has happened and needs to be confirmed by Subaru was with early production builds that the RTV pattern was not dialed into the exact dispense weight.
Honestly, you can waste a lot of time trying to tune RTV dispense through the dispense head, pump, flow characteristics of the system (hoses, type of hose material for pressure buildup, clamping), flow meter system (inline or external), dispense nozzle for bead width, valves for mitigated stringers (snuff-back), dispense speed, pump motor speeds, and finally the material itself for specific weight to characterize with a SPC/GRR analysis.
And you still won't be able to mitigate all defect at the dispense head. Man, I have seen so many tests for these systems that I honestly am surprised with the variations for dispense systems that ultimately affect each of these variables differently. Air motors, hydraulic rams, internal electric motors, hot melt pumps, large bucket rams, two-part mixers; ALL these systems have their pros and cons.
Regardless of how inconsistent the dispense is, RTV is not a big problem to worry about entirely. Just remember that the silicone will degrade over time because of thermal loading and vibration that will eventually separate the intermolecular bond between the two metal surfaces. Hence the small particles people showed in their videos after disassembly. Still, these RTV materials are no joke as they will hold items together for years and not suffer extreme separation. I had to take a 25-year old module that needed Remanufacturing, and that sucker had the RTV still stuck to the connector even when pried apart with Isopropanol and CO2 blasting to separate the bead. After RTV dispense and passed leak test, that 25-year old module was back to a car that needed the part (expensive part at that).
My only concern is when you have lubricants needing to flow from the oil pan and you have these 1-part RTV adhesives blocking some of the flow. The RTV can reflow (become fluid-like) with enough heat and oil applied to separate the water molecules binding it together, but the likelihood of it is very low even after multiple thermal cycles. My only desire from these scenarios is making sure Subaru handles the appropriate means to reduce dispense defects and ensure clarity to customers if they file warranty concerns. No engineer wants to see a car die because of deficiencies in the manufacturing, so I'm optimistic you won't see these issues be more prevalent.