L87 6.2L Block failures up to 2/week at my dealer, model years 2021+. Listen for Ticks!

joshhibschman · June 13

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

Edited June 19 by joshhibschman

newdude · June 13

L87 does NOT use a vacuum pump so that would be an invalid symptom on an L87.

L86 did however have the vacuum pump on it.

Edited June 14 by newdude

mds47588 · June 26

"- 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."

Obviously, every dealership and location are different. My dealership had no problem pulling an unsold truck off of the lot and tossing me the key to a brand new 2024 Elevation with a 8.6 miles. I use my truck to move things and make deliveries during my days off and I didn't stop with their loaner, and I didn't try to hide it either. I put 3284 miles on it during the just over a month that they had my truck. Pulled my 7' x 14' trailer to Nashville and back, Baton Rouge and return twice...etc, with nary a problem in addition to more local work. BTW, it was the 4cyl turbo and I was more than a lil impressed with how it performed.