Also, when the engine is warm, the top hose will be a lot cooler than you would expect. Thermostat is cheap. Order one and a new o-ring to go with it. If you haven't flushed your cooling system in 2 years, its time to do a flush and fill andyway. Even MB antifreeze is cheaper than a new radiator. If you have the plastic thermostat cover, order the metal replacement cover. The plastic one crack apart at the hose at the worst possible times. Mine came apart in my hands as I was pulling the hose off.