joshhibschman

@Cojam1 I posted an update after asking around a bit more over on hp-tuners forums

My dealer said they stopped doing half-bank replacements for this exact reason.

A GM Master Tech told me "we can't do it," but he didn't say "it can't be done." He added: - Blocks still fail from mechanical DFM even if ECM disabled. - Full disable requires different lifters, head gaskets, etc. - All flashes to the ECM show up in history, can be tracked by who did it - Third party flashes will void your warranty (i.e. HP-Tuners) - As of Global B, access to the ECM is encrypted Update -- For DIY electronic and mechanical, the cost appears to be ~$2,000 and 20+ labor hours for an experienced mechanic, also having to pull out and send in your ECM. Wish I had infinite free time to try! Will keep watching for someone to post experience with these products and circle back. DIY Electronic Disable HPTuners released send-in program for Global B ECMs! You have to pull out your ECM, send it in, and they "upgrade" it with a chipboard harness. Thing's you'll need: - Being OK with voiding your warranty - Couple weeks turnaround without your truck (pull and send in your ECM) - $800 for 22-24 L87 ECM mod: https://www.hptuners.com/product/gm-e90-ecm-service-global-b/ - $400 for the OBD2 connector: https://www.hptuners.com/mpvi3/#custom_form_mpvi2 - $300 ($400 on Yukons) for 6 License Credits https://www.hptuners.com/vehicles/#supported-vehicles - A Windows laptop to run their VCM Suite (free download) DIY Mechanical Disable Michigan Motorsports stocks a delete kit for L87. Don't know if this 2019+ kit actually goes to 2021 or if it still works through 2024. Should call and ask. - $400 Mechanical Lifter Delete Kit https://www.michiganmotorsports.com/camshafts-michigan-motorsports/cam-installation-items/2019-l87-6-2-dfm-lifter-delete-kit-dod-afm-6-2l-gen-v-kit/ Supplemental Notes on Non-DFM Motor Failures Many recent motor failures are coming from parts outside DFM/AFM/DOD. - 2023 Oversized Lifter Bore Defect, i.e. the lifter tube is to big, lifter rocks, causes a bent rod - 2022 Main Bearing Cap Bolt Defect, i.e. bad torque on the bolts, misaligns the crankshaft - 19-23 Oil Pump Defect, i.e. bad oil pressure, bad lifter activation - 2021 Plunger Spring Rod Wear , i.e. lifter spring rubs rod, causes a bent rod - Gas/Oil low on detergents lets carbon build up, jamming the lock-spring in the lifters

Just got my truck back after a block replacement at 29K miles, sharing some things L87 owners need to know. A month ago I heard lifter tap, not my first rodeo. I called around to see which dealers had a loaner, headed straight there and bent a rod about 100 yards from the service entrance. Would have made it if it weren't for a confused Prius. Truck was out for a month due to backordered blocks, visited the shop a few times to talk with techs. Check for ticks! Shop tech said use a stopwatch: - Fuel Pump Tick (OK): 1 tick/sec, on cold start idle, is normal and safe to ignore (loudest under rear of motor) - Lifter Tick: 5 ticks/sec on a warm idle is usually a lifter problem (loudest on top of the motor) - *Edit only for L86* Vacuum Pump Tick: 10 ticks/sec on a warm idle, vacuum pump problem (front of motor) - Quieter lifter ticks are from inside the lifter itself - Louder lifter ticks are from hitting a rocker arm - Higher the RPMs, higher chance of bending a pushrod. Keep it under 2,000 RPM if you've got lifter tick. - Common cause is DFM, bad cam timing from faulty imported parts, e.g. magnetic cam timing actuator. New L87 Blocks, Service Mgr said: - New blocks are backordered 3-5 weeks due to high demand. - New block quality is a gamble. Some fail out of the box, some fail later. Has had trucks with 3 replacements. - This shop's replacement rate is up to 2/week on Sierras, Yukons, Escalades, Tahoes, etc (2021-2024) Call around for repair (GMC, Chevy, Cadillac dealers) - Ask about parts backorder time, got a different answer from each dealer - Ask about loaners, few have them. Choices were small SUV or less, no hitch! Fine print limits loaners to 75miles/day no out-of-state. - It's a complex repair, if they seem sloppy on the phone, they'll be sloppy on the repair. After Replacement Observations (comparing old motor 0-miles feel vs new motor) - Major difference in responsiveness. Old motor had a 1-2 second delay to feel power. New motor is immediate. - Old motor had weird vibration, new motor has some but 80% less. - I'm running low RPMs for 500 miles, keeping it under 2K. Don't know if it needs break-in, but will baby it for peace of mind. - *Edit* auto-stop was disabled for the first ~50 miles Speculation, research to prevent sticky lifters, recommendations welcome - Gas: I run Premium, but will only do "Top Tier" stations now (https://www.toptiergas.com/). - Oil: Switching to Amsoil Signature despite the $$$$, will still change every 5K - Oil Filter: Switching to Purolator Boss - Auto-Stop: Bought an auto-stop disabler to get rid of those hasty stop-restart stutters - Randomly throw money out the window