My car makes a pretty nasty grinding sound for 0.5-1.5 seconds after cold starting it. It doesn't seem to do it with a warm engine, but pretty consistently does so with a cold engine (even on a warm day).

Today I popped the hood and had my wife start it while I listened. I had my head over by the belts and timing chain when she started it, and I heard the sound, but the sound seemed to be coming near the throttle body. I had her cut the engine off and cold start it again (awful, I know, but necessary for diagnosis), and it seemed to be coming from the area around the throttle body and intake manifold.

I poked around, and saw that my starter is right there where the sound seemed to be coming from. On a hunch, I started it and held the key in the 'start' position for a few seconds too long (also awful, but I was trying to replicate the sound), and I heard the same grinding sound that has been occurring for these past few weeks on cold starts. This makes me think the starter might not be disengaging correctly on cold starts.

Thus, I think the cold start grinding is likely related to my starter or flywheel. Is there any way to test and know for sure, without having to pull everything apart and look?

The car is a 2007 4 cylinder manual transmission 4 door SE with 173k miles. As far as I know (only had it since 109k), the clutch is original.

Hoping maybe it's just a starter... a clutch job on this car is beyond me.

Thoughts on Bendix vs flywheel?

 

If that is the area you suspect the sound coming from pull the starter, look at the teeth on the starter and bench test it. Next using a light and a mirror look at the teeth on the fly wheel through the starter hole. You will need a 19mm socket to turn the engine at the harmonic balancer. Turn it CLOCKWISE in short increments and inspect all the teeth on the fly wheel. Also, if the starter looks fine check it for lateral play as it could be a bad bearing or the throw out arm which is internal.

 

I went ahead and ordered a new starter. Planning to put it in this weekend. The grinding is getting worse, and I figure with the effort involved with removing the intake manifold to get at it, I'd rather just have the part on hand and ready to go. I'll take a light and mirror and inspect the flywheel in the process. I'm not getting any funky vibrations or anything like that, so hopefully the flywheel is in decent shape.

 

I put a new starter in it today. So far I haven't heard the post-start extended grind, so I may be in good shape. When I compared how quickly the gear on the new starter would snap back versus the old starter, the old starter gear moved back much slower. Makes sense why the old starter was disengaging too slowly So, perhaps the problem is solved.

I took a good look at the flywheel while I had the starter out. All teeth are present, and most look completely fine. There are a few that are a bit gnarled. I posted a picture of the worst appearing one. I'll post a separate thread to get opinions on the flywheel. Hopefully it is in good shape.

Thanks for the help!