Newbie intro and question

[elchivito]

Hello to all,

I've been reading here for some time and am really impressed with the wealth of experience among you all. I'm new to Mercedes as well as diesel but very anxious to learn. I've been looking at 300's for a while now but haven't pulled the trigger yet. Tomorrow I'm going to a nearby town to look at an 82 300SD with 227k miles. The owner is not it's first. He has 5 yrs of service records including timing chain replacement, valve adjustments etc. He states that all the electrics in the car work, but the tachometer is "intermittent" and won't register over about 2500 rpm. He says he hasn't looked into it as he doesn't depend on it. Speedo apparently works fine. This concerns me a bit as having no diesel experience I'd like to have the tach working for "educational purposes". My son, a new driver, will also be using the car and I'd like him to get used to using a tach also. Any suggestions on what this might be? Thanks and I look forward to more discussions here.