Dealer Denied Warranty Claim because of "Modifications?

[TrailJustin]

Story time.

A friend of mine recently had an engine failure on his 2024 Ford Explorer ST. The motor locked up and completely failed. He took it to the dealer, and they denied the warranty claim, stating that his aftermarket intake and exhaust caused the engine failure.

He then found an independent shop and paid around $14k to source and install a replacement engine. No, he did not get ripped off, and yes, there were multiple quotes. The Explorer ST is a 500-whp monster of an SUV. After the new engine was installed and the old motor was torn down, it was discovered that the crankshaft was actually broken in half.

“Photos to come.”

If you ask me, crankshafts don’t just break in half especially in a vehicle like this. These crankshafts are forged and machine-balanced before installation. There’s no logical way an intake or exhaust would cause a crankshaft to snap. So what can be done?

Magnuson-Moss Warranty Act​

The Magnuson-Moss Warranty Act protects vehicle owners by preventing manufacturers from voiding warranties or denying coverage simply because aftermarket (non-OEM) parts are installed or repairs are performed by independent shops. To deny a claim, the manufacturer must prove that the aftermarket part directly caused the specific failure.

This act exists so that, for example, if you run non-OEM suspension components and suffer a differential failure, the manufacturer cannot blame the suspension unless they can prove it caused the issue. In this case, the manufacturer would have to prove that an aftermarket intake or air filter caused a crankshaft failure. Even typing that out sounds ridiculous, which makes you wonder why they would try to argue it at all.

What you should do if they deny?​

First, remember that it’s not the dealer denying the claim—it’s the manufacturer. Ask for an appeal, request the specific reason for denial in writing, and contact the manufacturer’s corporate office directly. Have your VIN ready. The people at corporate handle these cases every day, and often claims are denied quickly just because the word “aftermarket” appears. Ask to escalate the case.

Second, consult a local attorney or draft a formal letter requesting that the claim be properly reviewed. In this case, the engine replacement was $14k installed, so it’s worth putting in the effort to fight it.

Here in California, we also have the Department of Insurance, which helps oversee warranty disputes. You can open a case with your local agency, and they can contact the manufacturer on your behalf. I’ve done this personally with a home warranty claim, and it definitely gets attention quickly.

Finally, after speaking with an attorney, you can take the manufacturer to small claims court and have a judge determine whether the repair should be covered. More often than not, it never gets that far once pressure is applied.