[aquavelva]

My 1997 E220 (W124) stalls while it is moving. This is not a regular occurance and happens once in a while. I have observed the rpm around 500 and speed is almost near 20 kmph when this happens.

Another issue that i have been facing is that while driving in start and stop traffic conditions, the engine overheats and the reading goes beyound the "100" mark. But as soon as the car is running in open stretch of road the engine cools and reading is in usual "80" to "100" mark.

Any suggestions would be greatly appreciated.

[dhanushs]

At 20kmph and 500rpm, you are lugging the engine. Please keep the revvs higher than idle rpm.

Regarding overheating, those are classic symptoms of a malfunctioning cooling fan. I'm not sure if the car has a second fan or a second speed for the fan, but either does not seem to work. May be a thermostat problem or an electric issue, or worst case, the fan is kaput.

[R2D2]

Originally Posted by aquavelva

My 1997 E220 (W124) stalls while it is moving. This is not a regular occurance and happens once in a while. I have observed the rpm around 500 and speed is almost near 20 kmph when this happens.

Another issue that i have been facing is that while driving in start and stop traffic conditions, the engine overheats and the reading goes beyound the "100" mark. But as soon as the car is running in open stretch of road the engine cools and reading is in usual "80" to "100" mark.

Any suggestions would be greatly appreciated.

I would get the water pump and electric radiator fan(s) checked ASAP. And if possible Don't drive without having this done. As dhanushs said at 500 rpm you are lugging the engine, switch to a gear that gets the RPM into minimum 1100-1300 RPM range @ 20 kmph.

[aquavelva]

Dhanushs & R2D2 : The vehicle stalls when i am at low rpm while in motion. Twice, while i was on a turn i had to slow the vehicle and it stalled. As i said The overheating stops as soon as the vehicle gets a low traffic situation. I will surely get the radiator fans checked. It is an Auto transmission and i have been revving the engine more thann 500 rpm if i observe that such a situation might arise.

Thanks a lot

[aquavelva]

Dhanushs : I am not an expert on vehicle mechanics but from what i have read on forums, the vehicle has a auxillary fan. I am not 'lugging the engine' intentionally. As it is an automatic transmission vehicle. while taking a turn i slow down and that is when i have observed that the stalling has occurred on 2 occassions. It may also be some electrical issue (Not sure).

R2D2 I would surely get the radiator fans checked ASAP.

Thanks a lot

[GTO]

Originally Posted by aquavelva

This is not a regular occurance and happens once in a while. I have observed the rpm around 500 and speed is almost near 20 kmph when this happens.

Known W124 issue. It could potentially be a blocked catalytic converter (average life is anyways 10 years), bad MAF sensor and also get your throttle body checked. BTW, have you changed your wiring harness? Merc went enviro-friendly with bio degradeable stuff that just doesn't last as long as in the older Mercs. Again, 10 years is the maximum life for the car's wiring harness (costs 40K to replace)

Another issue that i have been facing is that while driving in start and stop traffic conditions, the engine overheats and the reading goes beyound the "100" mark. But as soon as the car is running in open stretch of road the engine cools and reading is in usual "80" to "100" mark.

Its your cooling fan. As simple as that.

[majorpayne]

Originally Posted by aquavelva

Another issue that i have been facing is that while driving in start and stop traffic conditions, the engine overheats and the reading goes beyound the "100" mark. But as soon as the car is running in open stretch of road the engine cools and reading is in usual "80" to "100" mark.

Any suggestions would be greatly appreciated.

Have you checked the coolant level in the radiator? Do you find that the engine coolant depletes over a period of time? (It could be a week, it could be a month)

[aquavelva]

Originally Posted by GTO

Known W124 issue. It could potentially be a blocked catalytic converter (average life is anyways 10 years), bad MAF sensor and also get your throttle body checked. BTW, have you changed your wiring harness? Merc went enviro-friendly with bio degradeable stuff that just doesn't last as long as in the older Mercs. Again, 10 years is the maximum life for the car's wiring harness (costs 40K to replace)

Hi GTO: The Wiring Harness was replaced by the dealer in Oct 2002 (Goodwill) as per the vehicle history. Throttle body had been cleaned recently. The injectors were also cleaned. Is the MAF a part with MOT written on it ? If that is the one then we had also cleaned it. How much is the catalytic convertor for. Does it need to be replaced or can it be cleaned ?


Its your cooling fan. As simple as that.

I will surely get the fan checked.

[aquavelva]

Originally Posted by majorpayne

Have you checked the coolant level in the radiator? Do you find that the engine coolant depletes over a period of time? (It could be a week, it could be a month)

Majorpayne: The coolant level is not depleting

[cicero]

Do you have any problem with the air conditioning? If not, then this could be beyond the cooling fan. However, it is possible that the cooling fan is not running at the specified speed. Could be an electrical issue (at the relay box).

At high speed, for cooling purposes, the fan is not really needed (due to the ram air), even when you have AC on, and if some fan power is needed, it will go undetected. However at idle and at low speed, fan power is very much needed and that's where you see the problem.

Take the car to the dealership and get it checked asap, before you drive any further.

However you can do one check - next time when at idle or at low speed, switch on the heating in the car at the full blast - open all your windows otherwise you will not be able to sit. If the climate-control is set to auto, go for the manual option. What happens- your HVAC heater acts as an extra radiator. if you see some improvement, then it is the fan trouble.

[Viraat13]

Originally Posted by GTO

BTW, have you changed your wiring harness? Merc went enviro-friendly with bio degradeable stuff that just doesn't last as long as in the older Mercs. Again, 10 years is the maximum life for the car's wiring harness (costs 40K to replace)

A little off topic...

The engine harness doesn't HAVE to degrade in 10 years time. Mine went kaput after 13 years. A friends went bust after 9. No hard and fast rule about it.

But if you're trying to convey that it can be a cause of worry after a decade, you're spot on.

[benz220]

Cooling sounds like a check of the aux an relay may be in order.

Intermittent stalling - check the OVP relay and the fuel pump relay. By the way the fuel pump relay and aux relay are the same part so you can interchange in an emergency.