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My 2005 Infiniti G35 got pushed to 8000 RPMs for a minute without shifting out. I drove it for another 7-10 miles, then going downhill it lost power and finally died with a cloud of smoke coming from under the hood on the right side. It will turn over but sounds like it has no compression and won't crank.

What could be wrong? Do I need a new motor or can I fix this issue? The car has 170,000 miles and I love it, please help.

  • Welcome to Motor Vehicle Maintenance & Repair! Have you determined where the smoke originated from? – Pᴀᴜʟsᴛᴇʀ2 Jun 16 at 20:45
  • Nit pick: "turn over" and "crank" mean the same thing. I take it that you mean it'll crank, but won't start? – 3Dave Jun 19 at 18:53
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Redline on a stock 2005 VQ35DE engine is 6,500rpm IIRC (on the '06 cars and certain limited edition cars it was fitted with the so-called "revup" engine and for them the redline is 7,000) so 8,000rpm is at least 1000rpm above the redline. If you were accelerating to reach that 8k rpm the limiter should have kicked in at 7k (or 7.5k on a revup), although I've seen varying reports of the effectiveness of the limiter and some remaps remove it entirely. And of course you could have gotten to that by downshifting - to be honest though it doesn't make much difference - 8k is 8k.

Holding that for a minute is going to result in serious unpleasantness to say the least. With these engines (and from the symptoms you describe) I'm guessing the most likely scenario is valve float during the over-rev resulting in the pistons hitting the valves and bending them. There may be other damage to the pistons themselves but you aren't going to know until you get it apart to look.

Definitely don't try and start it any further - you risk doing more damage. Honestly though you're in for a big bill, it's not quite at the level of scrapping the block but it's going to need a new valvetrain at least.

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