You're forgetting one thing (Not your fault because it even stumps some trained mechanics):
When you test your starter off of the vehicle, you may very well see the small gear fly forward like it's supposed to do. But once it's on the car, it may not fly forward "Far enough" to engage the flywheel.
You'll either have to measure (Hard to do) and verify these distances, or bolt the starter up and crawl under the car and watch it engage. (Be careful)
On some rare occasions, you'll receive the wrong starter from the parts store. It'll bolt up, but since it isn't the right starter, it won't engage.
Now, if the starter gear does reach far enough, it also may not have the strength to turn the engine over. And that would make it "Whir" but not actually turn anything.
Your only way of finding that out is crawling under the car and watching its operation.
I hope this helps.
Saturday, January 23rd, 2010 AT 8:29 AM