What Is the GM Duramax Oil Cooler Lawsuit?
The GM Duramax oil cooler lawsuit is a proposed class action against GM over engine oil coolers in heavy-duty trucks. It is pending in the U.S. District Court for the Eastern District of Michigan as Hubof v. General Motors, LLC, Case No. 2:26-cv-13622.
The named plaintiff alleges a cracked cooler can make trucks lose engine oil. The trucks are 2024 to 2026 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD models with the 6.6L Duramax diesel.
Searches for a GM vehicle engine overheating lawsuit return several different GM engine cases. This case alleges oil escaping into the cooling system and a loss of lubrication, not track overheating.
Why Are People Filing GM Duramax Oil Cooler Lawsuits?
People are filing GM Duramax oil cooler lawsuits because the oil cooler allegedly cracks and GM denies warranty claims. The complaint says the cooler cracks during normal driving.
The complaint also alleges GM knew about the problem before it sold the trucks. It says GM never issued a recall.
Plaintiffs further allege that replacement coolers share the defect and sit on national backorder.
What Injuries Are Included in the GM Duramax Oil Cooler Lawsuit?
The GM Duramax oil cooler lawsuit includes three alleged categories of harm, all mechanical or financial. The summaries reviewed describe no bodily injury claim.
The three categories are engine failure, denied warranty coverage, and repair costs with downtime. No court has ruled on any of them.
Engine Oil Loss and Engine Failure
Engine seizure is a mechanical failure in which internal engine parts lock together and the engine stops turning.
The complaint alleges the oil cooler can crack during normal driving. Pressurized oil can then escape into the cooling system or leak from the truck.
That loss can starve the engine of lubrication. The complaint alleges this can lead to engine seizure or catastrophic failure.
Denied or Limited Warranty Coverage
A warranty denial is a manufacturer's refusal to pay for a repair that the owner believes the warranty covers.
The complaint alleges GM blames low oil levels on poor owner maintenance. It says GM uses that explanation to avoid paying for engine failures.
It also alleges GM often pays only for a new cooler when the engine needs replacing.
A cracked cooler can leave the dipstick low, according to an October 2026 Yahoo Autos analysis. The oil pump runs at higher pressure than the cooling system, so oil can move into the coolant.
The same analysis says GM's 2025 Chevrolet limited warranty booklet lists the integral oil cooler as covered. It excludes damage from failing to maintain fluids.
Repair Costs, Downtime and Backordered Parts
Repair cost is what an owner pays to fix a vehicle, plus the time it sits out of service.
Hubof bought a new 2024 Silverado 2500HD in December 2023. In June 2025, at about 16,453 miles, he heard a loud bang and found oil in the coolant bottle.
A GM technician reportedly found the cooling system filled with engine oil. The repair quote was $41,319.79, and GM did not repair the truck under warranty.
The complaint also alleges replacement coolers are on national backorder. One owner complaint to NHTSA from February 2026 reports 52 days out of service while waiting for a part.
Who Qualifies for the GM Duramax Oil Cooler Lawsuit?
You may qualify if:
- You bought or leased a 2024 to 2026 Chevrolet Silverado 2500HD or 3500HD with the 6.6L Duramax diesel
- You bought or leased a 2024 to 2026 GMC Sierra 2500HD or 3500HD with the 6.6L Duramax diesel
- You bought or leased the truck in the United States, not for resale, which the nationwide class covers
- You live in Idaho, since the complaint also proposes an Idaho class
You may not qualify if:
- Your truck has a gas engine or a different diesel, since the complaint names the 6.6L Duramax
- You bought the truck to resell it, since the proposed class excludes purchases for resale
- You expect a payout now, since no class is certified and no settlement exists
No class has been certified, so no one is a class member yet. No claim form or deadline exists. Some 2027 trucks may also be affected. Whether an owner recovers anything depends on class certification, the merits, and any settlement. Only a qualified attorney reviewing your vehicle records can confirm your position.
What Is the Current Status of the GM Duramax Oil Cooler Lawsuit?
The current status of the GM Duramax oil cooler lawsuit is pending at the earliest pleading stage. No class is certified, and no court has ruled on the claims.
The CourtListener docket entries this page reviewed are plaintiff attorney appearances dated September 24 and October 2, 2026. A published docket review as of October 6 found no appearance by GM. Court records can lag the live docket.
Hubof v. General Motors, LLC
Robert Hubof filed the complaint on September 24, 2026, and the court assigned Judge Robert J. White. The docket lists the cause as a diversity motor vehicle product liability case under 28 U.S.C. § 1332.
Dennis A. Lienhardt filed the complaint for the plaintiff. E. Powell Miller, Dana Fraser and Bonner C. Walsh later appeared.
| Court | U.S. District Court, Eastern District of Michigan |
| Case Number | 2:26-cv-13622 |
| Judge | Judge Robert J. White |
| Filed | September 24, 2026 |
| Plaintiff | Robert Hubof, owner of a 2024 Chevrolet Silverado 2500HD |
| Defendant | General Motors LLC |
| Plaintiff's Counsel | The Miller Law Firm P.C., Sauder Schelkopf LLC, Walsh PLLC |
| Claims Alleged | Breach of warranty, fraudulent concealment, unjust enrichment, and Idaho consumer protection law |
| Proposed Classes | A nationwide class of U.S. purchasers and lessees, plus an Idaho class |
| Relief Sought | Damages, declaratory and injunctive relief, a court-supervised repair program, and a jury trial |
| Current Stage | Early pleading stage; no GM appearance on the docket as of October 6, 2026 |
Law360 reported on October 9, 2026 a further proposed class action in the same court. It alleges engine oil coolers cause radiator contamination and catastrophic engine failure.
The case number, judge and counsel for that filing sat behind a paywall. This page does not treat it as verified.
How Much Is the GM Duramax Oil Cooler Lawsuit Worth?
The GM Duramax oil cooler lawsuit has no determined worth, because no settlement exists and no class is certified.
The complaint seeks damages for Hubof and the class, plus a court-supervised repair program. The reports reviewed state no total damages figure.
The sources reviewed found no GM recall and no extended warranty program for the cooler. Owners with a failure currently rely on the standard warranty process.
GM Duramax Oil Cooler Lawsuit Updates and Case Status
Here is the current status of the GM Duramax Oil Cooler lawsuit, updated with new filings, rulings, and case-count reports as they're confirmed. The Hubof v. General Motors class action continues in active pretrial proceedings as of October 2026, with no global settlement reached. See the full timeline below for every confirmed development since the litigation began.
GM Duramax Oil Cooler Lawsuit Timeline
GM customer service answers a Sierra owner about an oil cooler
GM customer service answered a 2024 Sierra owner's online oil cooler complaint in November 2023. Top Class Actions summarized this from the Hubof complaint.
Robert Hubof buys a new 2024 Silverado 2500HD
Hubof bought his Silverado 2500HD new in December 2023. He is the named plaintiff in the Duramax oil cooler class action.
GM issues Service Update N232430450 to dealers
GM's Service Update N232430450, "Possible Engine Coolant Contamination," told dealers to hold and inspect affected 2024 HD diesel trucks. It names no cause and is not a safety recall.
GM releases Bulletin 25-NA-052 on oil in coolant
GM released Bulletin 25-NA-052 on March 4, 2025 and revised it on March 25. It says oil in the coolant of an otherwise healthy engine may come from a leaking engine oil cooler.
Hubof's Silverado fails and GM issues Bulletin 25-NA-150
In June 2025 Hubof's truck failed at about 16,453 miles. That month GM also issued Bulletin 25-NA-150, "Engine Oil Leak," for 2024 and 2025 Silverado and Sierra HD diesel trucks.
An owner reports 52 days out of service to NHTSA
A 2024 Sierra 2500HD Denali owner told NHTSA in February 2026 about 52 days out of service. The truck awaited a backordered part under warranty. NHTSA does not verify owner reports.
Hubof files the proposed class action in Michigan
Robert Hubof filed Hubof v. General Motors, LLC, No. 2:26-cv-13622, in the Eastern District of Michigan on September 24, 2026. Judge Robert J. White is assigned.
Bonner C. Walsh appears for Hubof
Attorney Bonner C. Walsh entered an appearance for Robert Hubof on October 2, 2026, joining E. Powell Miller and Dana Fraser, who appeared on September 24.
Docket review finds no appearance by GM
A published docket review dated October 6, 2026 found no lawyer had appeared for General Motors in the Hubof case.
Law360 reports a further oil cooler class action
Law360 reported on October 9, 2026 a further oil cooler class action in the Eastern District of Michigan. Its case details were not publicly visible.
How to File a GM Duramax Oil Cooler Lawsuit
Filing a GM Duramax Oil Cooler lawsuit typically follows the 6 steps below.
- Confirm your truck and engine: Check that your 2024 to 2026 Silverado or Sierra 2500HD or 3500HD has the 6.6L Duramax diesel.
- Check your VIN for open recalls: Enter the 17-character VIN at NHTSA.gov/recalls and ask a dealer whether any service update applies to your truck.
- Keep every maintenance record: Save oil change receipts and service invoices, since GM allegedly blames low oil on poor maintenance.
- Document any failure: Record the date, mileage, symptoms, any oil in the coolant bottle, and what the dealer found.
- Save all warranty correspondence: Keep repair quotes, denial letters, and tow or rental bills tied to the claim.
- Consult a consumer class action attorney: Because Hubof is a proposed class action, an attorney can explain whether to wait or pursue a separate claim.
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What Evidence Do You Need for a GM Duramax Oil Cooler Lawsuit?
The evidence needed for a GM Duramax oil cooler lawsuit centers on maintenance records, repair orders, and warranty correspondence. The VIN and window sticker show whether the truck has the 6.6L Duramax.
Maintenance records matter because GM allegedly blames low oil on poor upkeep. Repair orders that record oil in the cooling system, not only a low dipstick, may also matter.
Warranty denial letters and repair quotes show what GM paid and refused. Only a qualified attorney can say which records a court would find useful.
What Did GM Allegedly Know About the Duramax Oil Cooler Problem?
GM allegedly knew about the Duramax oil cooler problem before it sold the trucks, according to the complaint. The complaint points to a November 2023 customer response, an August 2024 service update, and a March 2025 bulletin.
The complaint also alleges GM marketed the trucks as reliable and durable.
| Event | Actor | Date |
|---|---|---|
| Answers a 2024 Sierra owner's online oil cooler complaint | GM customer service | November 2023 |
| Issues Service Update N232430450, "Possible Engine Coolant Contamination" | GM | August 14, 2024 |
| Releases Bulletin 25-NA-052 on oil in coolant, revised March 25 | GM | March 4, 2025 |
| Issues Bulletin 25-NA-150, "Engine Oil Leak," on cooler seals | GM | June 2025 |
Service Update N232430450 covers 2024 Silverado and Sierra 2500HD and 3500HD trucks with the L5P 6.6L diesel. It tells dealers to check the surge tank for an oily black film and to hold affected trucks before delivery.
Bulletin 25-NA-150 tells technicians to inspect and, if needed, replace cooler seals before replacing the cooler. It states that engineering found many returned coolers "do not leak." A court has not weighed that statement.
A public NHTSA database review found eight owner complaints of a failed oil cooler or oil in the coolant. They cover 2024 to 2026 Silverado and Sierra 2500 and 3500 models. NHTSA does not verify owner reports, and one came from a fleet operator with a gas-engine truck.
No recall for the cooler appears in the sources reviewed. A dealer service update is an instruction to dealers and does not itself offer owners a free repair.
How Does the GM Duramax Oil Cooler Lawsuit Compare to Other GM Engine Lawsuits?
The GM Duramax oil cooler lawsuit differs from other GM engine lawsuits in engine, alleged defect, and procedural stage. It concerns a cracked oil cooler on the 6.6L Duramax diesel.
Three other GM engine cases are easy to confuse with it. None is part of Hubof.
| Case | Engine and alleged defect | Status |
|---|---|---|
| Hubof v. General Motors, LLC (this case) | 6.6L Duramax diesel; cracked oil cooler and oil loss | Pending at the earliest stage; no class certified |
| Powell v. General Motors, LLC | 6.2L L87 V8; connecting rod and crankshaft bearing failure and recall 25V-274 | Pending in the Eastern District of Michigan; no class certified |
| Matanky v. General Motors LLC, No. 1:17-cv-22209 (S.D. Fla.) | 2015 to 2017 Corvette Z06; cooling system overheating and power-reducing limp mode after about 15 minutes of track use | Hagens Berman lists the case as closed; a motion to dismiss was denied in full or in part |
| GM 5.3L V8 oil consumption class action (Siqueiros, N.D. Cal.) | 5.3L V8 trucks and SUVs; excessive oil consumption | $150 million class settlement; Mealey's reported final approval |
The Corvette Z06 case is the closest match to a search for a GM engine overheating lawsuit. It alleges overheating on a racetrack in a performance car, which is a different vehicle and defect.
The oil consumption and L87 cases involve other engines. Their outcomes do not predict a result for Hubof.
Frequently Asked Questions
What is the GM Duramax oil cooler lawsuit about?
The GM Duramax oil cooler lawsuit is about an engine oil cooler that plaintiffs say cracks in heavy-duty trucks. It alleges GM concealed the problem and denied warranty coverage.
Is the GM Duramax oil cooler lawsuit a class action or an MDL?
The GM Duramax oil cooler lawsuit is a proposed class action, not an MDL. Hubof v. General Motors, LLC was filed on September 24, 2026, and no class has been certified.
Is the GM Duramax oil cooler lawsuit an engine overheating lawsuit?
Not mainly. The GM Duramax oil cooler lawsuit alleges oil escapes into the cooling system or leaks out. That starves the engine of lubrication. The Corvette Z06 case, Matanky v. General Motors, is the GM overheating case.
Which trucks are in the GM Duramax oil cooler lawsuit?
The lawsuit names 2024 to 2026 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks with the 6.6L Duramax diesel. Some 2027 models may also be affected.
Has GM recalled the Duramax oil cooler?
No recall for the oil cooler appears in the sources reviewed. GM issued a dealer service update dated August 14, 2024, which the sources describe as not a safety recall.
Has GM settled the Duramax oil cooler lawsuit?
No. GM has not settled the Duramax oil cooler lawsuit as of October 2026. No class is certified, no claim form exists, and a docket review as of October 6 found no GM appearance.