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Grinding Ignition

My 2008 Honda Accord grinds when I start it up, not every time, but usually when it’s been sitting for hours. I used to think that I needed an oil change, because after I got one, the grinding went away. When it came back “Time for an oil change!” But I just got an oil change last week, and the grinding started again the next day. My dealership said it was no big deal and I could drive the car that way, it wouldn’t hurt the car.
Does anyone know what this might be and what I should do about it? Is it expensive to fix?
Thanks very much for your help.

Is it only when you turn the key to the start position? Does the noise stop when the engine starts running? Or does the the noise continue after the engine is running?

If the dealership said that it’s not a problem…Didn’t you ask them what was making the noise???

If it hasn’t been too long since you were at the dealer, go back and ask.
If it’s been more then 10 days…forget it, they’ve seen so many cars in the lat 10 days I doubt they would remember it. But maybe they wrote it down.

Then you could list the cause here so we can help you.

yosemite

The grinding is probably the pinion gear in the starter not meshing with the ring gear on the flex plate. This could be caused by a loose starter, a malfunctioning starter, or a damaged ring gear. The starter will need to be pulled to inspect it.

Thanks everyone for responding. Busted, I’ll tell them that. Yosemite, I’ll comment again when I find out, although I think once I do, I’ll tell them to do the work. I can’t imagine that a grinding in the ignition is GOOD for a car… And KN, it’s only when I start up the car when it’s been idle for a while, not when it’s running, and not if I start it up again a half hour later. And it lasts for 2 seconds and then it’s gone.

Definitely starter not engaging with the ring gear.

The problem might be with the over-running clutch on the starter pinion gear.

When starter pinion gear engages the ring gear on the flex plate and turns the engine over and the engine starts, the over-running clutch is supposed to disengage the pinion gear from the ring gear. If the over-running clutch sticks it holds the pinion gear against the ring gear and it makes a grinding noise.

When this happens the starter is replaced.

Tester

Honda has a bulletin for “Rattle at cold start up”. The noise is from the variable valve timing control actuator located in the camshaft gear, not in the ignition.

Toyota/Lexus has the same problem, I have replaced more than a hundred VVT camshaft gears on IS350’s.

A mechanic’s stethoscope might could be used to identify the source of the sound, either from the camshaft area as postulated by Nevada, or the starter motor area, as postulated by the others.

fyi to OP’er: When you use the term “grinding ignition”, that’s confusing to mechanics. It sounds like you think the noise is in the car’s ignition system. You don’t want the shop to start taking apart your ignition system unless there’s a reason to do so. When discussing this with your shop, don’t speculate as to the cause, just make sure they understand the noise occurs during “cranking”.

Just got my car back, the grinding noise turned out to be a VTC actuator, which took a few hours to replace. Thanks for your help everybody.

Heck, I knew that…NOT!

Was it expensive to replace? Just had my alternator replaced and mines (Honda Civic) been doing that when I start ever since (randomly, quick and after it sits like you mentioned)