these are the tips for getting it in shape i've found so far.....
A few notes regarding newbies to diesels and Mercedes W123 vehicles:* *First, owning a diesel is*a little different than owning a gasoline (petrol) powered car, but not so much so that you should avoid them. Second, these diesels won't win you traffic light races. When cold, they need a couple minutes or so to warm up for optimum driving but this does not translate to anything negative at all - it's just the nature of the beast so to speak. Air, oil, and fuel (2) filters are the only tune-up parts you'll need - there are no spark plugs or points or transistorized ignition system on a 300D. The MOST important thing is to keep the oil changed regularly (I prefer every 3-4 thousand miles or 3-4 months whichever comes first).* This car starts well and warms up quickly. Transmission shifts very smooth once car is warmed up. Gas mileage for a 300D according to EPA back in 1980 is: 23-25 city and 26-28 highway with an average MPG of 25 overall. With regular unleaded gasoline rising rapidly nowadays, a diesel-powered car may be the best alternative for many out there! And by the way since this was originally a car from up northeast area, it does have the engine block heater option - but I never needed it here in Florida! I have had years of experience with all sorts of W123 cars and this 300D has been one of the most trouble-free cars I have ever had...
The 1980 Mercedes 300D is a fantastic car. The engine is very sound and free of problems, provided you take some necessary steps. The in-line fuel filter should be transparent, this allows the driver to see any buildup that may accumulate from dirty fuel. This clogged filter may cause the car to lose power and and stumble while driving. This stumbling may appear like a huge engine problem and some repair shops may lead you into the premise that there is a major problem when its just a two dollar filter.
Some people may think that the "pings" and "knocks" are a nuisance, these can be remedied by using a great product called RED LINE this fuel additive provides lubrication for the top of the engine which reduces the pings and knocks and provides better gas mileage.
The pockets on the front doors should have some type of support inserted inside of them, because most people accidentally kick and crack these convenient hard plastic pockets. A small dictionary will generally provide enough resistance to prevent cracking.
Be sure to read the manual because you will find many secrets in the car. Location of drain holes. Manual sun roof controls if the motor burns out. and many other neat little secrets.
Check the Air filter,
Replace both fuel filters,
Run Lubro-Moly "Diesel Purge" through the system (undiluted)
Clean the EGR valve,
Clean the manifold fitting for the the ALDA,
Change the oil (I recommend mobil-1).
I may be forgetting some things, but the air filter and the Lubro-Moly should eliminate two potential sources.
The trick with that model (and older) diesel when the fuel has run out, is the system needs to be primed again. To do that, there is a priming pump on the side of the injection pump (IP). Look for a flat topped knob and unscrew it. When unscrewed, cycle it in and out until you feel pressure. When you feel that the system has pressure (is primed), screw the knob back into place and start the car as normal. There will likely be some bad knocking sounds until the system runs all of the air out.
The IP is an expensive unit, but I have never had to replace one. Sometimes a leak can develop at the base of the injector lines at the IP, which is just a matter of replacing the "delivery valve seals" (o-rings).
These really are very solid cars. Often neglected maintenance items include valve adustments and timing chains (stretched beyond spec).
I found this very helpfull except you forgot to mention one very important thing about how to bleed the fuel lines... before you start pumping the priming pump by hand, you need to loosen the bolt a little on top of the screw-in fuel filter (not the in-line filter) to allow a place for air to escape out...
then you can pump it 'til you feel pressure build up & then retighten the fuel filter bolt & rescrew the priming pump back like it was
I have a 79 300TD with a broken gas gauge & yep, it ran out of gas. It's my first diesel & everyone was making out like it was going to be a big thing to get it restarted ( including my boyfriend ). I've been working on my own cars for years & figured it can't be "That" hard. I ended up here... Thanks guys!... You got me started in the right direction but I ended up hand pumping for a long time with no results until I finally found out from a book I got a hold of about loosening the bolt. I hope my post saves someone else a lot of time & headaches!
And Thanks cracker for describing the priming pump knob, I found it easily 'cuz of your description. Mine happens to be flat as you said & made out of plastic with ridges on the edge (for anyone else who has my model ).
Bear in mind that there are TWo fuel filters in the engine compartment. One clear plastic on and one that looks like an oil filter. You might have another filter to replace.
Also, be sure to adjust the valves.
This site can be invaluable:
Sorry. An "italian tuneup" is a way of flushing the injection system with clean fuel by keeping the car in a lower gear and running it hard, preferably under load, like up a hill at 4000+rpm.
First of all, the key to success with diesel cars is:
CLEAN FILTERS AND CLEAN OIL AND CLEAN FUEL TANK.
So how do we accomplish this?
First of all, we have to make sure your fuel tank is not full of water and crude. Dumping it all out and cleaning the tank is a big messy job and may not be necessary, but you should put in a "biocide", something that kills algae (yep, they love diesel fuel) and removes water, and a fuel conditioner.
Then drive the car and see if it runs smoothly. If it seems okay, then change the two fuel filters immediately! That should get rid of all the crud you picked up with the cleaners. You may have to do this twice in a row with the filters. They aren't expensive. The main filter is only about $12 and the secondary filter is only about $5.
Once you have the fuel situation under control, then you should change the oil and filter.
If you went to a Mercedes DIESEL specialist, they could get the car in shape for you---you just tell 'em it's been stored for a year and they'll know what to do.
Personally I'd put in a quick $500 for oil change, filter change, fuel tank additives, safety check, tire check, belt and hoses check, and I'd flush out the brake fluid, too...and....do a valve adjustment.
I'd recommend a 3,000 mile service schedule for oil changes. As for filters, etc., you can buy a service booklet at the Mercedes dealer that will tell you everything you need to do---although it sounds like Uncle might still have these books in the glove compartment.
So to summarize:
Once the repair shop has you up and running, resolve yourself to frequently change the oil, pay attention to the fuel filter change interval, and ALWAYS ALWAYS, put in a diesel fuel conditioner when you fill the tank----REDLINE makes a good product.
Clean fuel solves 90% of diesel car problems!
don't drive it TOO FAST. These older diesels do NOT like to rev up. Try to stay under 76 mph if you can. Change the oil a lot, adjust the valves every 30K, change your filters often and flush your coolant every two years.
My mechanic told me it was a common mistake with my car the oil filler cap has a gasket inside it and " meine ist kaputt" in friendly words and it literally blew all the oil out of the top while I was driving.