how to know radiator is bad?
 

Hey guys, been having problems ever since the beginning of time keeping my 500E cool.

I've tried JimF's cool harness but it still runs 100C+ in cold weather

I'm wondering if it is my radiator

how do you check, what are signs?

Man, a radiator is little more than a water reservoir, if you are running hotter than what spec is then you need to do a systematic elimination of possible faults:

coolant level?, Serpt. belt, water pump, themostat? water channels plugged? engine temp sensor, coolant temp sensor, fans working at right temp? aux fan,if equipt? air flow in front of radiator blocked by accesories?

A "bad" radiator is one that leaks, small leaks can be fixed Plugged radiators can be flushed.

'Man, a radiator is little more than a water reservoir'

I don't agree. This IS the principal thermal exchange device designed to cool the engine, and it contains narrow passages that are easily plugged by precipitating sludge or rust particles. If the cooling system has been meticulously maintained since day one, you should never have a problem until it leaks. Normal maintenance is less ideal, and having a radiator rodded out is a very common procedure to rectify this problem.

A somewhat plugged radiator usually can function adequately in normal driving, but can't handle more severe conditions. If the cooling system temperature shoots up to 100C, but tends not to 'overheat', then the radiator is probably not at fault. Look to the systems that regulate the temperature, or for a faulty indicator circuit.

Steve

I understand that, that's why I'm asking about this. Before I wasn't sure if it was running hot because it was normal to run that hot. But after putting the harness in and it's still running hot, i realize something is wrong, that's why i'm asking.

I'm going to have the dealership look at it.

IMHO, 100 degrees is not hot for a 500E, or even a 300E or E320.

It is in the normal operating temperature of the engine.

At 100 degrees, the thermostat is not even in the fully open position, yet.

We owners of W124's freak out a lot about operating temperature because the temp gauge moves a lot.

Does everybody realize that in response to owners like us, Mercedes designed a buffer in the temp gauge of W210's so that the gauge stays at 95 degrees when the temp goes between 95 and 115 derees celsius?

After 115, the gauge starts to record actual temperature.