I have experience with deisel benzs but not a SD. i had a 300D '79 without a turbo. the SD series had turbos. anyways, make sure the car starts right up, if it kind of turns a few seconds or has a rough start up, the deisel injection pump might be going. thats about a 1000 dollars for a new and about 800 for a rebuilt. i live in Socal as well, its not the summer its the winter, sometimes it might start rough. make sure the glow plug are good, turn the car to the on position, without cranking the starter, and the little glow plug dash indicator should come on and go off pretty quick, if it doesnt the car may need new glow plugs, but thats fairly cheap. All in all, deisel benzs last a lifetime, my mechanic has seen some deisels last 400k miles.