When were the engine's valves last adjusted? Adjustment is due every
24,000 kms.
And your starting technique: At 0 degrees C. M-B wants the accelerator depressed and held there while the motor is being cranked, let off the accelerator when the motor fires. At -20 degrees C. M-B wants the accelerator pumped three times before cranking the motor, then the above procedure.
You are probably on the right track about the grounding strap... the battery negative ground cable is the first thing to check and the ground strap... which is by the starter if I am not mistaken... needs to be replaced.
No, a bad cable just won't be able to deliver as much current which is critical when cranking. If you leave the car until it's reached a final cold temperature, say 8 hours and it starts OK, but won't crank about the same after sitting for say 24 hours or 48 hours at the same temp, that suggests you have a small load that is not turning off and draining the battery.
You can disconnect one of the battery leads and insert an amp meter. With everything off, the current should only be 10ma or so, which would be the clock, etc. If it's substantially more, something is drawing current and you need to track it down.
If the battery has been drained overnight there are some suspects on your model:
The cursed climate control "servo" is reported to drain a battery. The car's power antenna is known to drain a battery. A stuck power window switch can drain the battery.
If you need to replace the servo I'd suggest you check out a digital retrofit system from
My mechanic looked after the car for the previous owner. He checked out everything and in the shop it starts every time. Valves were done by him, the glow plugs fine. He's baffled! He said I may have to take it into Mercedes to have them run diagonstics on it. Is there anything else before I take it to them?
My mechanic looked after the car for the previous owner. He checked out everything and in the shop it starts every time. Valves were done by him, the glow plugs fine. He's baffled! He said I may have to take it into Mercedes to have them run diagonstics on it. Is there anything else before I take it to them?
If you are talking about the starting problem it is either fuel (pump, filters, algae etc), electrical (battery, relay, glow plugs, block heater etc.) or mechanical(vacuum, valves, worn rings etc.) . Based on the report of a battery drain problem I would certainly fix the problem or replace the battery before I took it to the stealership.
If you want to troubleshoot the battery drain problem try here:
In this entire discussion there isn't a good description of exactly how it behaves when it won't start. If it barely turns over, and won't crank for more than a min, that is a very different thing than if it turns over normally, with plenty of cranking ability, but won't fire at all, etc. Does it always have this starting problem, or does it depend on temperature? Does it start perfectly when warm?
Did the mechanic leave it out over night in the cold at similar temps to when the problem occurs? BTW, I wouldn't have much faith in any mechanic who said you have to take it to MB for them run "diagnostics" on the car. There isn't any special diagnostic that MB has for a 30 year old car. It's just basic problem solving and elimination that any decent diesel mechanic should be capable of doing.
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