Hello all,

What a way to get introduced to the Mercedes family! You will probably be getting a lot of questions from me, as my fiancee bought a 1979 300SD from Green Benz in L.A. As you know, these people are crooks. We now have a vehicle which may or may not be worth the effort it will take to get it up to speed, but I am so impressed with the loyalty & information exchange on this forum that I am willing to give it a try.

My first question (and I know it may sound stupid, but this is my first experience with a diesel) is, do you use the same anti-freeze as a regular engine?

Second, none of my gauges (temp,oil pressure,fuel,glow plug, etc) or dash lights work. When we first received the vehicle, the battery was flat. Tostart it,I put in a battery from another (gas engine) car and when the Benz started, some of the lights/gauges worked. But after I changed back to the battery that came with the car, nothing worked and even with a 24 hour trickle charge, it will start, but no lights or gauges. Does the battery have to be at full charge for these items to work, or should they work off the generator when the vehicle is running? The fuses all seem to be good and the headlights come on, butthey dim as the batterycharge goes down. This seems to indicate a generator/regulator issue - any thoughts would be appreciated.

For all you people who love to tinker with cars, I'm sure I will provide plenty of entertainment, butI'll get this Green Benz clunker running decent with your help.
This should keep me busy for a couple of daysand then I'll be backlooking for more assistance.

Thanks in advance,
Ian

 

Couple of days.
Good job it isn't an S Class.

1. Anti freeze is the same as for gas engine BUT two things. MB usually run at 50% mix, since it is not just antifreeze but supresses boiling point. In addition aluminium engines (or part aluminium engines) are very particular to antifreeze type since anti corrosion inhibitors need to be present. My recommendation is only use MB antifreeze BUT since this is an old car I guess you could use 50% antifreeze recommended by one of the aftermarket garages/companies without undue risk.

Your battery is DEAD.
Once it has been below 12.5 volts its useless. Throw it away. Buy a new one but ensure that the charging circuit is working correctly otherwise you will end up with another bad battery. Recharging does not return the battery to AOK even if it appears to be OK by holding enough charge to start the car. it will suddenly let go at the worst possible time. IRREVERSIBLE changes occur within the chemistry of the battery. It will never be correct again.

Good luck

Stuart