I think my starter motor has finally died. My 850 with 186,000 miles started fine last night. I then heard a few random sounding pinging noises which stopped after about 10 seconds. I drove up the block, shut down the engine. I was unable to start the engine. The starter would not engage. This morning the car started without a problem. I drove around the block, shut the car off and again the car's starter will not engage. If it is the starter how difficult would it be to replace it myself? Thanks for the help.

Are you sure it's not just corroded connections?

Thanks for the info. I know what I'll be doing Saturday!

the starter itself is not a problem to replace. Two bolts in the tranaxle housing and one bolt on the positive cable connection for power and a spade bit.
Also there is sometimes a support bracket on the non working end of it.

The issue is getting past all the other mechanicals (fan shroud mainly) to get to it.

I would suggest you remove the fan motor assembly and also the splash guard at the bottom of radiator area to get to it.

The good news its ..its a lot easier than taking out the alternator!

I would give yourself 2 to 3 hours depending on your abilities.

Good luck!