W126 Grinding Starter
 

I have a problem with my '87 560SEL that is slowly getting worse. Occasionally, instead of immediately engaging the ring gear and turning the engine, the starter spins freely making a grinding or gnashing sound. I'm assuming that the problem is that the pinion is not popping out far enough. The starter appears to be tightly and correctly mounted.

Is it likely that I need to replace the entire starter or can I just replace solenoid (starter drive??)?

Thanks
jlc

Could be your flywheel is damaged..

Had the same problem on a Volvo 940, most times it started ok, but once in a while it you make the grinding/set your teeth-on-edge /scare the dog sound.

I had to remove the gearbox to change the flywheel oil seal so I took the oppurtunity to look at the starter..it was ok.. I then took a look at the flywheel and there was visible wear along one portion of the gears. Changed it out and the problem was solved. I think the trouble starts with a flaky starter which then grinds the flywheel gears down. The starter gets repaired but the damage is done.

Later on I was told that since 4-cyl engines usualy stop in one of two position.. 2pistons up and 2pistons down, it would be possible two re-install the flywheel 90degress off (as compared to the current position) this would take the damaged gears out of the area where the starter would 'catch' . This wouldn't have been possible on my car as it ha a crank position sensor on the bellhousing,,I would have hadd to drill a new hole and rebalance the whole thing,.

Best of luck
Anil