Does the W202 C200 petrol have a radiator expansion tank?

[Steed]

Quick question,

Does a petrol engined W202 C200 have a separate radiator expansion tank?

Radiator cap doesn't have a pressure marking so it so I presume its not a vent to atmosphere system, but I'm unable to locate the expansion tank and you wouldn't have thought it was that difficult to find, possibly brain fade on my behalf, car drives fine.

Can anyone confirm the location?

 

[Uncle Benz]

If it has a metal radiator cap on the top of the radiator it is likely the type that doesn’t have an expansion tank. If one were fitted there would be a pipe stub on the neck just below the cap with a pipe on it. The pipe would run to the tank. I can picture the type you have. The radiator top is like a cylinder shape.

 

[grahamcol]

As above. I've had two C200 202's. One had the expansion tank (with pressure cap) and the other didn't have the expansion tank, the pressure cap being fitted on top of the radiator.

 

[Steed]

Thanks Uncle Benz and Graham

You are both correct the top of the radiator is a tank shape, and despite having no pressure rating stamped on it the cap does have a pressure relief spring inside.
Occasionally the low water level light will come on even though the water level is fine, any suggestions on what to check?

 

[Uncle Benz]

I think the sensor is on the top of the radiator. It may be showing its age if the level is good. Mercedes often use the low coolant level light if there is a problem with the cooling fan too. Yours may be the type with a carbon brush that often wears.

 

[Steed]

Appreciate the reply thank you.

There is a sensor on top of the radiator, but it looks more like a temperature sensor rather than level, as no obvious sign of any moving parts when I removed it.

Is the carbon brush on the cooling fan motor ?

 

[Uncle Benz]

My memory for these things is not what it once was! You probably have a radiator fan that is attached to the water pump pulley, rather than an electric one mounted to the radiator. Some of the water pump mounted ones have a thermostatic centre which mechanically brings the fan to speed when required. The older w201 used to have a fan mounted to the pulley, but it was brought into play electrically via a carbon brush and an electromagnetic clutch. I cannot remember clearly if early w202 had the same system. Anyway, if the fan is electrically operated, either mounted to the radiator or on the water pump pulley, the coolant warning light can also indicate that something is wrong with that system.

 

[Steed]

Having just looked at a few diagrams, it looks like the sensor one top of the radiator is for coolant level. I will look at options for testing or replacing it and also check operation of the radiator mounted fan.

Thanks again.