[vasanthjn]

I bought a second-hand W124 E220 last month. It has done 73000 kms on the odo and in the last 3 weeks I have driven around 600 kms (after I bought).

Off late I am experiencing an unique problem. During slow speed (10 / 20 kmph) my engine shuts off, this has happend on two different days (This happened on two days within a span of 3 weeks). Both the times within a span of 1 hour the engine has shuts off around 5 to 6 times, which is really dangerous considering that the steering wheel gets locked. The other thing I noticed is that the engine is getting hot and the meter shows around 95-100 C (am not sure whether this is normal) when I experience the above problem. I also noticed that the idling rpm is around 500-550 rpm.

I discussed the issue with my mechanic and he mentioned that this may be due to quality of fuel. But I am not convinced with his answer. But today he mentioned that this may be due to low idiling rpm.

Experts, please provide your opinion in this regard.

[Psycho]

Sounds like you breather pipe has come off from the intake pipe above the engine, this pipe is known to harden and crack causing starting and idling problems if air gets directly to the engine bypassing the MAF sensor.

Please check this and confirm.

[V-16]

Originally Posted by vasanthjn

I bought a second-hand W124 E220 last month. It has done 73000 kms on the odo and in the last 3 weeks I have driven around 600 kms (after I bought).

Off late I am experiencing an unique problem. During slow speed (10 / 20 kmph) my engine shuts off, this has happend on two different days (This happened on two days within a span of 3 weeks). Both the times within a span of 1 hour the engine has shuts off around 5 to 6 times, which is really dangerous considering that the steering wheel gets locked.

The other thing I noticed is that the engine is getting hot and the meter shows around 95-100 C (am not sure whether this is normal) when I experience the above problem.

Its difficult to say what the causes are until the car is seen personally but i will try to leaborate what the most common ones are for your problems.
Over and above what Psycho has adviced, i think you should check the coil.
Firstly its not normal for this car to cross 80-90C unless you are doing stop and go in bumper to bumper traffic for a great amount of time. Then maybe 100 but very rare. For this, get the cooling system checked for clogging, rust, blockages, leakages and always fill in a good coolant. Please also check the visco coupling of the electric fan. This may reduce the fan speed and will result in the car heating like you say it does.

Another thing that could cause this problem is a faulty cam sensor. That can be checked on a star diagnosis system easily.

Now as you say this problem occurs when the engine crosses 90-100C and when it has run for about an hour, maybe the coil is getting hot. A few minutes rest will cool the coil for it to start transmitting the current again.
Then again it may be a fuel pressure problem or as small as a dirty filter or clogged injectors.

I i noticed that the idling rpm is around 500-550 rpm.
I discussed the issue with my mechanic and he mentioned that this may be due to quality of fuel. But I am not convinced with his answer. But today he mentioned that this may be due to low idiling rpm.

I think its time you looked for a better mechanic. Firstly the rpm of 500-550 is too low. it should idle at around 750-800. That just may be the reason your car is stalling in low speeds. First get the rpm increased to 750-800 and see if your problem persists, if its still there, then at least you got the rpm right.
Next check the coil and then the fuel related problems mentioned above that may have occured.

IMHO, fixing the rpm should stop the problem. Still, do get your radiator flushed.

I would recommend you start in the way above from the easiest i.e. increasing the rpm and thereon but do not go changing any parts unless you are absolutely sure. Alos it wont hurt get a second opinion from another mechanic too.

Please let us know if the above have been helpful in solving your problem. Hope it has.
Regards.

[Otto]

well, perhaps you could try keeping the engine revs a little high at the times you think this problem occurs - and see if the engine shuts off. I agree 500rpm for an idling engine is too low.
How's the smoke? is it clean? that would eliminate air/fuel problems.

[Jaggu]

First check the fuse box, i faced the exact same issue in chennai long back. Went to the nearest shop bought a packet of those ceramic fuses and plonked em in. Everything started working fine.

So first check the fan, then move on to the cooling system. Maybe a good idea to do a complete radiator flush and fill up with new coolant also.

As mentioned above find a good merc specialist, should be easy to find in chennai.