Diesel Engine Specific Aid

Hi, My wife has a 350SD (W126 - 1991) with 146k miles. We have had it only for the last 15k miles or so. The car has developed a strong throbbing, low frequency vibration or shaking (the whole car) when stopped at a stop light (for example) after it has been driven for a while and is well warmed up. It is slightly noticeable, but much less severe, when started up from cold. Otherwise, the engine seems to run smoothly and be OK at higher RPMs. I have noticed that the idle speed drops a little from, >6500 to

Just recently purchased a 1981 300TD TurboDiesel and was wondering if other owner's are able to actually hear the turbo spool up?

The date is March 12, 2007. I get a strange sort of metallic noise that seems to be temperature aggravated. It seems to be engine RPM related, but I can't be certain. All winter I heard it, most at AM startup. I don't think it goes away at speed but can't hear it over other engine and road noise. It seems load related. At 25 mph in town it could be aggravated by light throttle pressure and sort of disappears on no load with a matched speed and throttle. I live in Fallon, NV, so it was cold. The last couple of days I have been in Blythe, CA, and it has been very warm - about 90.

I am currently dealing with a very frustrating starting problem with my 300D. This is the symptom: I turn the key in the ignition and sometimes it will start and sometimes it won’t. If it doesn’t start I proceed to turn the key between the off position and the start position. Eventually it starts, sometimes after doing this once, sometimes after 10 attempts. At the beginning of this problem, I knew nothing about automotive electrical systems, so I thought it was the starter and replaced it with a remanufactured Autolite starter from Kragen/Checker Auto Parts (I know this was probably a bad idea). Well, the problem continued and since I already dropped off my (probably) good Bosch starter for a core refund, it’s too late to go back.