The rubber "U" shaped hose connecting the water pump to the thermostat is a well-known failure point. The hard bends in the stock hose always end up cracking and leaking, but since the water pump thermostat assembly is tucked up above the subframe, it can be difficult to pinpoint the leak. When you upgrade your OE rubber hose to the ECS aluminized silicone hose, you don't just get a longer lasting, more flexible hose, but also one that's better suited to withstand high underhood temperatures. Due to this hose's proximity to the downpipes, it's subject to higher heat levels than other underhood hoses. It's subjected to?extreme heat?almost the entire time the car is being driven, as well as during cool-down when the car is parked. While BMW installed a small heat shield from the factory, it's ill-suited to withstand the temperatures placed on this hose.
ECS set out to beat the heat, using silicone because of its more pliable nature as well as its resistance to?heat. The next step was wrapping it with aluminum to offer further protection from the exhaust system and keeping the?coolant flowing at a more consistent temperature as it passes through this hose.
When performing this upgrade, it's an ideal time to replace the water pump and thermostat. Recommended replacement at 60,000-80,000 intervals.
