So I changed the starter and flywheel in my 2000 blazer and it worked fine for about a week. Then this morning it starting to make the grinding noise again and now won't start. I don't know what else to do

 

I would start by checking the gap between the starter and flywheel when the bendix is energized. To do this you'll need to remove whatever covers are required to see the flywheel where the starter meets it. Then remove the positive cable from the starter but leave the solenoid wire connected. Have someone turn the key and engage the starter so it extends and meshes with the flywheel but does not turn the engine. You can then get a visual on how the starter and flywheel meet. I don't think that is your problem but it's a place to start. There shouldn't be an issue there but you never know. If there are shims between the block and starter, those should be removed. My first car had shims installed for some reason and it ate the teeth off the flexplate within a few months of owning it. I believe an engine stops in the same place every time which is why the teeth will wear off in only one spot.

 

i was having a similar problem in my 97 blazer, the outer bolt hole is cracked which seem to make the back end of the starter raise while i was tightening the bolt, which made the gear end of the starter lower away from the flywheel. i placed a nail between the starter and the block on the opposite side of the outer bolt from the flywheel, which is accessible through the wheel well and doesn't require you to remove the starter just loosen the bolts until you have enough room to fit the nail in place then tighten the bolts. for me doing this has stopped the grinding, although the bolt does come loose every now and then and needs to be tightened up. if anyone has questions feel free to email me at [email protected]