General Motors has revised its turbocharger replacement bulletin for the 3.0L Duramax LZ0, updating the part number for the turbocharger oil feed pipe. The newly specified part is the same one we've previously identified on the 2027 LZ0 engine.

The change appears in GM Service Bulletin # 25-NA-202, titled LZ0 Turbocharger Replacement, which was revised on October 14, 2026.

The bulletin is now on its fifth version, having originally been released on October 21, 2025. GM specifically identifies the latest revision as an update to the turbocharger oil feed pipe part number.

The newly listed pipe carries GM part number 40009797.

The 2027 LZ0 Connection

We've spent considerable time examining the changes GM has made to the 2027 3.0L Duramax, including differences that weren't included in the company's original announcement.

One component we've previously discussed in several videos is the turbocharger oil feed pipe.

Our research using the GM dealership parts catalog confirmed that part number 40009797 is listed for the 2027 LZ0.

Now GM has updated its turbocharger replacement bulletin for earlier engines to specify that same part.

The bulletin covers 2023–2026 Chevrolet Silverado 1500 and GMC Sierra 1500 pickups, along with 2025–2026 Chevrolet Tahoe, Suburban, and GMC Yukon models equipped with the LZ0.

Although the bulletin does not identify the 2027 model year as an affected application, the revised oil feed pipe part number matches the one found in our research into the new engine.

Could the Updated Pipe Address an Oil-Flow Restriction?

This is something we've been interested in investigating, particularly given the turbocharger failures reported on some LZ0 engines.

The turbocharger depends on a continuous supply of engine oil to lubricate its rotating assembly. Restrictions in that supply can cause accelerated bearing wear and potentially lead to turbocharger failure.

There have been concerns involving the oil feed system on these engines, including the possibility of debris collecting in the small screen associated with the turbocharger oil supply.

GM has also investigated this area.

Engineering Information bulletin PIE0832, involving P0299 turbocharger underboost complaints on certain LZ0-equipped trucks, included instructions to inspect the turbocharger oil feed pipes for debris or obstructions.

That is particularly relevant now that GM has updated the oil feed pipe part number in its turbocharger replacement bulletin.

Could the updated pipe incorporate a change intended to improve oil flow or reduce the possibility of a restriction?

It's possible, but we haven't confirmed that.

We also haven't established whether the new pipe uses a different internal screen, restriction, or oil passage design.

GM's latest bulletin doesn't provide an engineering explanation for the part-number change. Without comparing the earlier pipe to 40009797, we cannot determine whether the revision affects oil delivery.

It's a component comparison we'd like to make.

What GM Now Requires During Turbocharger Replacement

The updated bulletin continues to instruct technicians to replace the turbocharger oil feed pipe whenever a turbocharger replacement is performed under this procedure.

The primary components listed are:

The repair also requires additional gaskets, seals, clamps, and other single-use components identified in GM Service Information.

GM lists 10.6 labor hours for the bulletin-specific turbocharger and oil feed pipe replacement procedure.

The bulletin also instructs technicians to document when the next engine oil change is due or how much oil life remains.

GM Continues to Emphasize Engine Oil

One detail that hasn't changed is GM's statement regarding engine oil and turbocharger failures.

According to the bulletin, GM Engineering has found that some failed turbochargers had been operating with incorrect engine oil, low engine oil levels, or both.

Dealerships are instructed to remind customers about the importance of using the correct engine oil and checking its level.

The bulletin does not identify every turbocharger failure as an oil maintenance issue, nor does it establish a single cause for all LZ0 turbocharger failures.

There are several possible causes of insufficient turbocharger lubrication, including low oil level, restricted oil passages, contamination, and problems elsewhere in the engine's lubrication system.

Replacing the oil feed pipe helps address the possibility of a restriction within that component during a turbocharger repair. It does not necessarily resolve an underlying source of contamination.

Another Confirmed Part Number From the 2027 Engine

We've already identified several changes involving the 2027 LZ0 through GM documentation and dealership parts catalog research.

The turbocharger oil feed pipe is now another component that connects the updated 2027 engine with the service procedures being used on earlier models.

The timing is notable, with the revised bulletin arriving as GM begins transitioning into 2027 production.

What remains unanswered is whether part number 40009797 represents a functional improvement to the oil feed system or a different type of parts revision.

We'll continue looking into the earlier oil feed pipe design and the changes incorporated into the 2027 component.

For now, we can confirm that GM's October 14, 2026 bulletin specifies the same turbocharger oil feed pipe part number listed for the 2027 LZ0.

Source: GM Service Bulletin #25-NA-202, Version 5, October 14, 2026, Document ID 6985816.