I drive a 1999 E300 Turbo diesel. It is in mint condition with about 38,000 miles. My father owned it before I did and he babies cars.

I replaced one glow plug at 24K miles, and two more at 26K miles.

I had a lady hit me about 5 weeks ago and the car is just getting out of the body shop (body damage to front right of car, but did not hit engine). However, they had to remove the engine to fix one of the rails.

The service shop is now calling and saying that all 6 glow plugs (Are there 5 or 6?) have to be replaced because all are worn. Est. cost of about $1,000. They say it has nothing to do with the engine being removed or the accident, it is just time to change them.

It seems odd to me that I have change 3 within the last 10-12K miles and now all 6 need to be changed, and all at once.

1. How long do glow plugs typically last?

2. Do they always go out at once like this?

3. I have the extended warranty from Mercedes (up to 100M miles). Should I have the dealer fix this or can I go to another repair shop that handles Mercedes and get them to fix it. Will that void my warranty?

4. Any idea how to find a good mechanic that is not with a dealership.