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Mitsubishi Evo Owner Finds Forgotten Socket Left In Engine From The Factory

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Have you ever heard one of those stories about a surgeon leaving a sponge or something inside a patient? What happened to a Jalopnik reader and 2006 Mitsubishi Evo MR owner is essentially the same idea: he opened up his engine, and found a forgotten socket inside.

Chris, the Evo’s owner, had owned the car since it had four miles on the clock and has now racked up over 64,000. He hadn’t had to do any major work on the car since he’s had it, save for some brake and suspension work.


Eventually, he started hearing some ticking noises, and he decided to see i the valve lifters needed some work. When he got the valve cover off, he found this:


See that thing there? That’s not part of the engine. It’s part of a part of a thing used to build the engine. It’s a socket.

Chris posted his pictures on the EvolutionM forum and managed to fish the socket out from the little nook it’s been nestled in for over a decade. The socket was wedged against cylinder one’s exhaust valve spring, the motion of which seems to have caused this gash in the socket:

Chris noted the manufacturer of the socket, Nagahori Heavy Industries (NAC), and reached out to them to confirm that they are a supplier to Mitsubishi Motors Japan. It appears that NAC is a supplier.


Chris reached out to Mitsubishi to see about determining if the forgotten socket caused any damage to his engine he should be aware of. Here’s how Chris describes what Mitsubishi was willing to do:

And after a lot of back and forth they say the vehicle is out of warranty, and they will only cover the $ 300-700 of diagnostic fees at a Mitsu dealership ($ 155/hr, quoted 1-2 hr for drive-test diagnostic, then 4-5 hrs to pull valve cover to investigate upper valvetrain for damage) if the socket is determined to have caused any damage.

Meaning, if the dealership says it’s mechanically fine, then I pay the fees...

to which I explained it’s akin to finding a fly in one’s soup, but didn’t get sick, however it doesn’t explain how or why there’s a socket there in the first place.

Thus we’ve reached an impasse.

So, Mitsubishi left the socket in the engine during the engine’s initial assembly, but they’re only willing to pay for the fees of determining if the forgotten socket caused damage if there actually is damage.


Considering that the socket was in direct physical contact with that valve spring, and considering the damage the valve spring did to the socket, you’d think at the very least Mitsubishi should replace that spring.

If the socket was a commonly available one for home mechanics, like a Craftsman or a Snap-on, that would be suspect; but the make of socket fitting with what’s used at Mitsubishi’s factories and the worn spot on the socket sure seem like this is something that’s been in the engine since it was built.


I reached out to Mitsubishi for comment, and will update the post if they respond.

In the meantime, I guess Chris can enjoy the use of one well-lubricated and slightly damaged socket?