Newbie from Portland, OR saying hello!

[WrightSounds]

Well Oversize, I checked the air filter and I stand corrected. That thing was FILTHY. And clogged. It's gone now. Seems like something so cheap and simple to swap out wouldn't have gotten away from the previous owner. Maybe because it's so cheap and simple is why it was overlooked 

[Tony66_au]

Thanks, Tony. I forgot you were in Australia, but now that we're a global economy and all ...

LOL Yeah well i have been buying stuff Stateside for years Jason, the hotrod market demographic is too small here so we get bugger all of the good stuff and even with freight costs its often 1/3rd cheaper especially since your dollar dropped below ours.

Between Summit, Jegs, Napa, Classic industries, Autohaus, IPD and the insane Mopar shops you guys have, not to mention a far better range and in a lot of cases better quality so even simple stuff like Thermo fans and Exhaust components we cant get here are cheaper and better than the best available here in Oz.

And when I was building Classic Trucks and Bus's the USA is a veritable playground of goodies for Detroit diesel muscle AND the Guys n Gals I deal with are friendly as hell on Skype or via email and usually love a good chat.

[Tony66_au]

I'm loving the input guys!

Tony66: I'm very intrigued by the vacuum system and all the tubing. I think it's pretty genius. I've watched the Mercedes Source YouTube videos showing how to use the hand vacuum pump to diagnose the problem. I'm a bit leery but I might give it a go!

Once you get used to it the system is fairly simple and a Vac pump and gauge is a must have item, The diaphragms can be a sticking point but you will usually find that some mook has disconnected something instead of fixing it and half the issue or more is un doing shitty half arsed repairs.

Trust me when I say that turning the key and watching your central locking work and hearing that clunk as the fuel flap locks is almost as good as sex once you get the system sorted out.

3 words my friend,  Git her Dun.

[WrightSounds]

Thanks for the encouragement Tony66! I saw this today at Harbor Fright: http://www.harborfreight.com/brake-bleeder-and-vacuum-pump-kit-69328.html Seems like it will get the job done.

[Tony66_au]

Maybe!

Vac testing is all about leakdown.

By this I mean creating a vacuum and holding it, then seeing how long it takes the vacuum to drop.

Chasing a leak this will do the job but it looks a bit cheapish to be truly effective on some of the finer testing.

That said if it is all thats available and the price is right then its a good start!

Tony

[ZCarFan]

Sorry about that WrightSounds, I basically mean that for driving over 55-60 that the gearing is too low, in my opinion, leaving the engine revving too much for a Diesel.  As-is you will see about 3000 rpm at 70 mph.   The 2.65 final drive ratio used in the 450SEL 6.9 and 560 SEL would put the engine at about 2500 rpm at 70 mph.  Doesn't sound like much, but it helps.

The 80's 307 Oldsmobile v-8 has a similar power curve as the OM617.950 and they used as low as a 2.14 final drive to achieve good fuel economy without overdrive.  I mention it as I feel it provides a useful analogue when examining good practices with high torque, low speed engines.

[JasonP]

Mine is around 3,100 RPM @ 70 mph. I always wondered if that was too high.

[WrightSounds]

Sorry about that WrightSounds...

No problem at all ZCarFan! That makes sense to me. And I love learning about all this. I was wondering about the RPMs, too, since mine is also running around 3000rpm at highway speeds. But the engine and ride is smooth so I figured that's just the way it is. Thanks for the clarification!

[andyatcrux]

The back window regulator not working could be as simple as cleaning the switch that is in your center console. Have you tried the switch on the door itself? I had the same issue that was resolved by some electrical contact spray on the switch. They gunk up. If it is making a noise but not working, then removing the panel to get to the regulator may be the only way to fix it. That is another topic if you go that route.
The thermostat is a 5 minute change. Really easy access. AutohauzAZ.com  is a great source for parts. Highly recommended. The local Harbor freight has that Mityvac vacuum tester BTW

[WrightSounds]

Hi Andy,
Saw your other reply before this one! Greetings!
Haven't messed with the window much at all. Thanks for the tip, though. I'll have to read about how to pull the switch out. I've been reading about pulling off the door panels for the last 5 days  I have close to zero experience working on cars so I have to build up (false) confidence before I tackle any of this stuff since it's all new to me. Or at least new to me in terms of a car of this caliber. I had no problem messing with my '84 Chevette when I was 16. I'm a little more cautious now that I'm older and my toys are more expensive.

I did change the thermostat! I got one at Napa over on SE 9th and Morrison. Wow what a difference, really. The car was taking   s o    l o n g   to warm up. And it never hit anywhere close to 90˚C. Ahhh. Much better now.

I saw the vacuum pump at Harbor Freight but cheap-me wanted to go home and print one of their 20% off coupons. But lucky for me I've got a mechanic friend next door that is loaning me his pump.

Thanks for the responses!

[andyatcrux]

This being my first diesel and Mercedes, I am slowly learning all about this car myself. I did minimal work on my gassers. It is a real pleasure learning about these old cars because there are so many information resources out there. Sounds like you are taking care of the high priority stuff first. The thermostat was one of the first things I did when getting mine. I also did the Citrus Flush when changing to the proper coolant (it had the green stuff), which you will likely read about at some point. Careful if you do this. It needs to be done carefully so as to not leave any residue of the citric acid. Anyhow, I am getting off topic. Enjoy the new car.