GM’s L87 V8 Problems Get Another Look
GM’s L87 V8 is known as one of the most problematic modern truck engines because of its many failures, recalls, and lawsuits. Now, Dave’s Auto Center is taking another look, searching for new evidence and a possible fix.
The engine builder thinks the real culprit might be a messy combo of crankshaft surface issues and the variable-displacement oil pump. To make things even messier, he’s just found damage to yet another part, which only adds to the mystery.
In the video, the aim is to find a solution for owners whose engines do not qualify for replacement under GM’s current diagnostic rules. The investigation is still in progress, and the suggested fix has not yet been tested.
A Damaged Lifter Could Be Part of the Problem
Cracking open the engine, the builder finds a bent pushrod, a lifter that’s seen better days, and a camshaft lobe that’s clearly been through the wringer. He figures the lifter spun a full 180 degrees in its guide, probably because the plastic retainers just couldn’t keep it in line.
This opens up a new theory beyond just crankshaft and oil pressure woes. That busted lifter could have scattered metal shrapnel through the engine, which might explain the damage on the number-one main bearing.
A handful of connecting-rod bearings are polished in all the wrong places, which the builder sees as proof of metal-on-metal contact. He thinks these scars back up his theory: the oil film that’s supposed to protect the bearings and crankshaft is vanishing when it’s needed most.
Still, the teardown can’t say for sure which came first – the oiling issues or the lifter carnage – or if either one explains every L87 meltdown.
Dave’s Auto Center/YouTube
Could Higher Oil Pressure Help Prevent Failures?
The builder’s fix? Reprogram the variable oil pump so it keeps oil pressure up, even when the engine’s just loafing along or idling. Right now, the pump drops pressure to save fuel, but he thinks that move leaves the bearings exposed.
Testing is still underway, though. The plan is to run these modified engines on a dynamometer, then take them apart to check for bearing wear and metal debris. He is also considering whether stronger lifter retainers could prevent the damage found earlier.
Dave’s Auto Center/YouTube
New GM V8 for New Buyers
If you’re eyeing a new Silverado 1500 or Sierra 1500, GM’s rolling out its sixth-gen small-block V8s for 2027. The fresh 5.7-liter L76 and 6.6-liter L78 promise more power and new designs, but cylinder deactivation is still along for the ride.
That makes the lifter issue worth watching, but it doesn’t mean the new engines will suffer the same fate as the L87. For now, the builder’s fix is still in the experimental stage, and owners will have to wait and see if it’s a real alternative to swapping the whole engine.
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