Opinions wanted *Please*: Longevity & Pricing for a ’95 300D

[RunningTooHot]

I am looking at a 1995 E300D that has the 606 normally aspirated 6 cylinder. I am wondering about the longevity of this engine, as the car has just over 350,000 (apparently mostly highway) miles on it. If it was a 617 engine, I wouldn’t even think twice about it, but…

Here’s the kicker: the car has been serviced like clockwork by a Mercedes dealer, but ONLY according to the factory recommendations. The problem is that the factory requires oil changes every 7,500 miles, which is more than double of what I would usually want to see. (I certainly hope that the 15-40 oil that the Mercedes dealership uses is diesel rated oil!) My concerns would obviously be about bottom-end wear, i.e., bearings and cylinder wall clearances.

If anyone out there has a ’95, or any other 606 powered car, can you tell me what to expect for oil pressure at idle when the car is completely warmed up? (Assuming 15-40 oil)

Any ideas as to what a realistic price should be, considering excellent condition, but very high miles?

Thanks so much again everybody!

Glenn