Mercedes Forum - Mercedes Benz Enthusiast Forums - New to me '84 300D. Some questions??

I just bought an '84 300D with 182,000 miles. I have a few questions about operation and maintenance.
-I am planning on purchasing a maintenance manual from Bentley.http://www.bentleypublishers.com/mercedesbenz/300d/ Is this a good one to get? I had one for my VW GTI and liked the format.
-What is a good online source to buy parts?
-The car seems to have good power as I have to climb 2000 feet in elevation to get home and it handles this well. However I can't detect ANY turbo noise. I have no Mecedes diesel experience but quite a bit of American truck experience. My '03 Ford F350 diesel has noticeable turbo noise when it spools.
-The A/C does not work and the heater temp output is low. Any ideas of things to check first? Also, what is involved in converting to R134? I am mechanically competent but have never worked on an A/C system.
-I have heard to keep the engine RPMs down to promote longer life. What should I use as a redline and cruise RPM? So far I have been trying to drive under 3000 rpm. To conservative?
-I have not heard or seen the electric fan come on in the week I have owned the car. Does this come on other then when using the A/C?
-Lastly. I have read to keep engine coolant temp under 100C True? Too hot?

Thanks for any help.
Phil