CRANKING sound on engine start

bag_of_rice

Hello there!

What causes a "cranking" sound on engine start? It doesn't last long, just upon engine start and is gone when the engine is running. What must be done to fix the cause?

PF_Flyer

Might need to be a little more descriptive on the sound. Is it like a rapid, loud clicking? Could be the starter since it's only happening at startup.

Some YouTube vids with various noises
https://www.youtube.com/watch?v=KFdA0nLasKs
https://www.youtube.com/watch?v=rY0ENaUA_Uc

One of them sound familiar?

bag_of_rice

Yes, the first short video is closest to what i'm experiencing, though i noticed this happens on warm weather especially.

PF_Flyer

Seems likely that it's something with the starter drive gear and/or flywheel. The starter drive gear wears down over time and winds up not being able to engage the teeth on the flywheel. The noise is created as the gears grind against each other. A couple of pictures will help illustrate. First, just a basic diagram. The starter drive gear pushes forward to engage the flywheel


When that starter gear or the flywheel teeth get worn, the starter gear will spin against the flywheel teeth and make that noise. Here's a picture of a worn starter gear


You can see how that gear would have trouble engaging the flywheel as it pushes forward. The damage/wear to the teeth of the gears could be on the starter, the flywheel, or both.

Here's one of a flywheel with worn/damaged teeth



But the only way to know exactly what's going on is for a mechanic (or you if you happen to be a do-it-yourselfer with the skills) to get in there and inspect things.

Mr_Shiftright

Yep, the starter should be pulled and examined and so should the flywheel, to make sure it's not damaged (hope not!).

PF_Flyer

Yes, thinking POSITIVE thoughts!

Mr_Shiftright

Well if the flywheel teeth are irregular, it's gonna chew up the new starter pinion gear, so......