Hi there

My 1990 190 has began to overheat in traffic and it appears that the electromagnet cooling fan does not seem to operate
when the engine begins to get hot.

The car also seems to suffer from starting from cold and seems quite ' sluggish' at low RPM.

I have only recently taken ownership of this car, which has only covered 7,500 miles from new ( fully documented).

I have replaced the plugs, oil, filters, ect and flushed the cooling system through.

Apart from that the car drives like new ( which it all most is I guess).

If any one has any words of wisdom I'd like to here from them.

Many Thanks

Simon

Replace ALL of the fuses in the fuse box. They will biodegrade over time. Even if they look good~

Do them first.

Also, there is a green or red switch on the cylinder head that can fail and cause this...

Good luck.

Check your thermostat. It is a very easy test. Remove the thermostat ( it takes about 3 miniutes on this car). Boil it on the stove and use a thermometer to see when it opens or if it opens all the way. I was baffled because the thermostat on my 190e 2.6 was only opening a crack. On the highway the temp was fine, but would shoot up quickly in traffic. Hope this helps you. I wrestled with the problem for a while. I didn't think it was the thermostat because it opened enough to be cool on the highway. Usuallt the thermostat will stick open or not open at all. I flushed the cooling system several times and took it to "professionals" to have it flushed. Found out the professionals that I took it to didn't know jack.

Benzmac,
You mentioned the green and red switch, do you know what it's called and do you guys carry it?
Kodiak

Its called the fan switch. It sits just behind the oil cap on top of the engine. There are two or three types. One type is three prong and the other is two prong, they also vary in color as Benzmac mentioned. The trigger of the fan at about 105-110 on the guage.

1990 with that low a mileage?!! Quite a find. Undoubtedy the fuel system will be somewhat gummed up as it has spent most of it's life sitting. This would be my first suspicion for running problems. What on earth did the previous owner do with it? I have put more miles than that on my c280 that I just bought in April.

Check the timing. Retarded timing can cause overheating, hard starting and sluggish performance simultaneously.