New 1983 300D Turbo
 

What's up. Just bought a 1983 Mercedes 300D with a Turbo.302k on the odometer and it runs. Needs pretty much everything, previous owner did not take care of it. New battery. I have new glow plugs for it and it supposedly has a new glow plug relay, but the glow plugs in there don't work. The dash light GP symbol does not correlate to the glow plugs I don't think so though. Anyways, I will post some pictures up later! Oh btw I paid $500 for it. It does run amazing though.

Troubleshooting glow plugs is pretty easy.

What should happen is:

Turn key to "run"
Glow plug light illuminates
Glow plug light shuts off
The engine should now be able to start

The relay energizes when the key is turned to the run position. The relay provides current until either the key is turned to "start" and released back to "run", or the timer times out the relay after ~1 minute.

You have parallel glow plugs, so if one is dead the others will still work.

If you put the key to "run", wait 10 seconds, crank the engine, and it starts within 5 seconds of cranking, at least the glow plugs have some function.

Anyway, we'll need more info from you to diagnose further.

Lot of basics to do.
New set of copper/bronze fuses
ALL fluids and filter changes
Adjust your valves.
Fluids include your radiator.

You have a GP relay on the drivers side fender. They very seldom go bad.

Welcome to the forum!
And remember ... the only stupid question is the one you dont ask

Good advise so far.

The relay has a fuse too, remove and inspect carefully, they are know to obtain a hair line crack.

I posted a pic of the location in post #14 here:
http://www.peachparts.com/shopforum/diesel-discussion/365934-well-my-240d-glow-plugs-failed-morning.html

Welcome aboard, Rookie! Lots of great advice on here, not much from me. My M-B Diesel is in an S-10 race truck that's pretty stripped down so the Mercedes body, suspension, and brake stuff I haven't dealt with. The good news is that there are guys who have and they're willing to share their experiences without a lot of ego - good folks!

My glow plug system is really basic, using a continuous duty Ford starter relay so it doesn't apply to your situation.

I have done some serious engine work (new crank seals and main bearings, new turbo, new injectors, etc) so I'll chime in if I actually know something. Otherwise I turn you over the the experts.

Dan

Ok thanks for the tips guy. They are very welcome. So I found out that my glow plug relay is full of water.. How that happened I have no clue. I assume the previous owner is responsible. It would make sense that the glow plugs are burning out. Well that and they are the crappy auto lite ones. I have another question though. The transmission on this will shift without the key in or brake pedal held down... Any clues on how to fix it??? It is almost an electrical mess, but I am slowly but surely figuring it out. My sunroof ain't working either. I am waiting on parts for a brake caliper rebuild for all. Unless somebody has all 4 for sale and they are in good condition lol. Thanks guys!!!

The bit about the shifter moving in and out of gear without a key in the ignition or the brake pedal pressed isn't an issue.. that's just how it works. No shift interlock in these caars.

BTW, as advice from someone who bought a basketcase 300D and eventually parted it out: go around the car and tally all the costs that you will incur bringing it back to whatever state you are trying to get it to. Then, look at what cars in that condition are going for. You may find that you can spend quite a bit less money in the end by buying a nicer one and keeping this thing as a parts car.

Oh, and don't worry about not getting "repair experience" from a $2000-$3000 300D, if that's what you are trying to do with this car. Any 30-year-old car will definitely give you that.

I appreciate the advice. Yeah I bought her as a fixer upper. My daily driver is a 2013 F350 6.7L Diesel. Part of finding everything that's wrong is half the fun!! I tried searching but is there a symbol table??? Like what everything means?? The doors have some kind of electric lock but I don't see a button for it. Once again thank you for all the help

The doors have vacuum locks :). They are operated by the plungers -- there are no buttons. I don't exactly remember which plunger operates all doors (I think it's only the driver's plunger), but I do think that both exterior door locks operate all plungers... I've never had a 'Benz with working central locking, so I'm guessing what I think I remember reading in the owner's manual.

Speaking of which do you have an owner's manual for the car? If not, I may be able to dig up one to send to you... it may not be the exact year, but not much changed for your car between 1982-1985 that would be reflected in the owner's manual.

Yeah no owners manual at all. I have a half rigged diesel maintenance manual lol.

Oh, and nice truck, dude! How is the 6.7 stacking up so far?

Even if you keep the car and fix it up, I would still make a full inventory of what needs to be replaced. Can't hurt, and that way you can plan everything out.

I think you can get old repair manuals for the car through STARTEK, a website on which Mercedes publishes repair manuals for older models. If they ask for a credit card number, they aren't going to charge you anything, they are just doing that to confirm where you live.

As far as an owner's manual, I have a decent 1983 240D/300D/300CD Owner's Manual sitting next to me. It's yours if you want it -- just PM me a mailing address. It's handy for educating yourself on how all the features in your car are supposed to work.

Ok, so I was poking around my engine just looking at what to tackle next. I stumbled upon the ALDA and what looks to be an upgraded switchover valve. The line that goes off the ALDA is just chilling and not connected to anything. The switchover valve looks to be hooked up to the automatic transmission valve thing next to the ALDA. The Banjo bolt line is connected to the switchover valve. Also when I took the banjo bolt out to clean it, it was covered in black OIL and soot. I figured out the Glow Plug issue for those are didn't catch it above.

Anybody ever create a simpler linkage system? Anyways, once again thank you for the advice and help.

Ok, so I have started tackling unbolting pieces from the engine, yet I am stuck. If somebody can show me a video or something how to get the turbo, exhaust off. Do I have to take everything off in pieces? Because I have everything loose and it still feels like something is holding it on there. I unbolted the turbo drain pipe from the bottom as well, trans dipstick, banjo bolt and line to switchover valve, air filter assembly, etc. Any help would be great.