W211 E230 Engine Start cranking sound
 

Greetings to all! I am in a desperate need for help on starting issue. The starting sound is cranking and taking a longer time to start.

[Please find the video clip of the cranking sound in the attachment below]

1. It happens only when I turn off the engine for at least 2 hours or cold start
2. I have experiment it by turning off the headlight, radio and A/C before starting (The chance of cranking sound is lesser to 20% of occurrence). If I turn these 3 things on, the chance of cranking sound is about 100%.
3. The success rate of starting the car is 100%. However, I fear that it might cause some damage to any electronic parts or control unit of the car

Information about my car:
2008 E230 V6 2.5 Facelift
Mileage: 90,000 KM

Have anybody ever encounter the similar problem? If so, what is the part that I choose change or diagnose? I would be very thankful to all the comments and opinions!

hi
first of all, I think you must diagnose battery and alternator. Maybe because of bad alternator battery doesn't charge well. If the alternator is good, then battery might be faulty.

Hi Fakhri,

Thank you for your reply!

That's on my mine as well, the alternator and the battery. For the battery, I am currently running on Bosch battery for W211 E230. However, the battery status gauge presented in green color ( which should mean it is healthy ). Are there any case where the status appear Green but actually it already went bad?

For the alternator, one of the repair shop told me to change to BOSCH alternator instead of the Dealer alternator. What is your thought on this? Would I go for it or buy the dealer's alternator.

Hi, if functioning well I don't recommend to change the alternator. I encountered almost the same thing. Both of mine, alternator, and battery was faulty. First I changed the battery, everything was ok, but after a time alternator stopped charging the battery, I repaired alternator, changed some relays, coils inside.

Maybe alternator doesn't charge well. because of this battery is weak, and can't start car
Maybe alternator is well, battery can't store charge

If these two is ok, maybe there are problems in glow plugs, air-flow parts, or starter, or diesel/petrol pump etc.

After I bought a car, I learned that it is very hard to find a certain problem, a lot of things depends on each other and the same problem may occur for different reasons. I recommend to diagnose these parts consistently

Thank you very much for sharing your experience! Currently, my battery gauge appear Green which mean it is in a good condition. However, it might be faulty though. I guess I can start off by checking the battery charge and repair the alternator first. I will follow through your recommended steps. I wish the problem will be solved when I check the battery and alternator. Thanks again for the recommendation. If you have any further information to share with me, please feel free to!