I recently took my car to mech because it was acting like it had alternator problems. Mech told me alternator is bad and rplaced. Got it back and it went dead again. Mech told me replace battery. Did so. Went dead after one day. Mech said bad alternator and replaced. Car is again dead after 70 miles and I am rippin my hair out. What tests can I do to find real problem? Thanks.

You need to see if there is something draining the battery. Put an ammeter in series with one of the battery cables and its battery post and see if it draws any current with the ignition and everything else turned off.

If it is drawing current start pulling the fuses one at a time while observing your ammeter. When the current drops after pulling a fuse that is your leaking circuit. If after pulling all your fuses and you are still leaking current, get a wiring diagram and start looking at the other circuits that are hot all the time and not fused in the fuse box such as the starter solenoid, heater blower motor, glow plug circuit and whatever else you can find in the wiring diagram.

Good luck,

Welcome to the forum.

I have the real problem and I'm now going to tell you exactly what it is:



















Your mechanic is an idiot.


Now that you have recognized the real problem, follow Larry's advice as indicated above. Larry is usually short and to the point, so, if you are unsure of what he's talking about.........post again and we'll walk you through it.

You do need an ammeter that is capable of reading 100 milliamps or less.

Thanks so much for the advice. Car is back with mechanic today but if it still doesn't work, I'll try your suggestion.

Thought the good ones were called "Technicians" these days...

Kudos to Larry on his recommendation; I just went through this very same procedure -

And I like Mr Carlton's observation - PC be darned!

bnc

After I had my (now ex) mechanic "fix" and oil leak on a diesel car and in the process, he shaved the head without resetting the valve seats deeper into the head (resulting in piston and valve interference), I have had reservations with having work done by any of them.
I recently was to busy to fix the oil leak on SWMBOs '82 300D, so sent it to the independent Eurpoean cars mechanic. when the car came back, they said that they couldn't get a gaxsket for the IP. They claimed that the rocker cover was sealed up tight, but that there was a leak from the rear crank seal and I would need $100+ to fix that. That'l be $250 thanks.

I took the car home and fould that the leaks had not changed. I degreased the engine and found the cam cover was still leaking even though they had used the blue silicone gasket on the seal. I took off the cover and found that there was plenty of the blue stuff on the outside of the gasket, but none between the gasket and hte head. Hmmm. Did they even remove the cover??
I nextturned my attention to the fuel pump, where the oil seemed to be dripping from. I sealed that up tight, but hte leak persisted unabated. I used an inspection mirror and found that the leak was coming from the side plate on the IP (different IP to that used in USA). Taking the fuel pump off, and then the side plate, I found that the gasket was not positioned correctly, and there was no way to hold it in position to ensure a good seal. I brought out the blue stuff and sealed the side plate, without the neoprene gasket.

I have since degreased the engine, including up thru the vents in the bottom of the bell housing. I have no leaks on the car , especialy not any from the rear crank seal.

Can you imagine why I am so cynical about the abilities of the mechanics I have dealt with?

There ARE good mechanics out there, many of them work on MB vehicles.
I just don't know any of them.

I have learned from this forum, enough to tackle any work on our cars, with the exception of engine rebuilding (and I may venture there anyway, with help from this forum)

ps, sorry about the rant.

__________________
Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.