The VQ40 shipped with a mis-manufactured secondary chain that literally saws through its own tensioner shoes — it was the subject of a TSB and a class action. We replace the chains, tensioners and guides at your home.
This one isn't normal wear — it's a manufacturing defect. The VQ40DE in the Frontier, Pathfinder and Xterra left the factory with secondary (upper) timing chains whose links were mis-stamped, leaving edges sharp enough to act like a file. Those sharp links run against the tensioner shoes thousands of times a minute and slowly cut through them. Nissan acknowledged it in a technical service bulletin, and it became the subject of a class-action settlement — that's how widespread it was.
As the chain saws into the shoe, slack develops in the upper chain drive, and you hear it: a rattle from the driver's-side front of the engine at idle that gets louder under load. The slack lets cam timing drift, which is when codes like P0011 and P0021 (cam timing over-advanced) show up. The shavings the chain carves off the shoes don't vanish — they circulate in the engine oil until the filter catches them, or doesn't.
The end of the road is the chain cutting fully through the tensioner shoe. With the shoe gone, the chain runs wild — it can skip teeth or contact the cases, and on an interference engine that means valves and pistons meeting. The fix is well understood: updated chains that don't have the sharp links, new tensioners, new guides. Done once with the corrected parts, it doesn't come back.
If your Nissan is doing any of these, this is the likely cause:
The defective chain doesn't stop cutting — every kilometre at idle and under load removes more tensioner shoe. Once the shoe is cut through, you go from a noisy engine to a chain running unrestrained on an interference V6, and that's a bent-valve outcome. The class action existed because this failure wrecked engines. If your VQ40 is rattling, the cheap window is still open — but it closes.
Yes — the upper chains are serviced with the engine in the truck through the front of the engine. It's a long day of work, not a shop-equipment problem. We bring the corrected chain kit, gaskets, oil and tools to your home and the truck stays put.
It's hours of book labour to open the front of the engine, billed at dealer rates with markup on every part — some owners were quoted even more than the typical range. We quote one flat price for the complete corrected kit, agreed before we start, and that number doesn't grow mid-job.
There was a TSB and a class-action settlement, but those windows have closed for most owners by now given the truck ages. It's worth confirming your service history before paying anyone — we'll tell you honestly if there's a path worth pursuing first.
Because the old chain has been carving its tensioner shoes the entire time — they're damaged goods even if they're not cut through yet. The corrected chains plus new tensioners and guides is the complete fix; anything less leaves worn parts behind a brand-new chain.
Send it over for a free second opinion. I'll tell you straight what the job actually involves — and if their quote is fair, I'll tell you that too.
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