Mishimoto has developed a performance low - temp racing thermostat for the BMW M52, M54, and M56 engines. This Mishimoto racing thermostat is ideal for modified engines that demand more from their cooling systems. Our thermostat begins opening 48F (27C) earlier than the stock thermostat to allow coolant to flow into your radiator and begin shedding heat sooner. This thermostat comes pre - installed in a durable OEM - quality housing and fits many BMWs including E46, E39, and E85 chassis. Like all Mishimoto performance products, this BMW M52, M54, and M56 thermostat is backed by our Mishimoto Lifetime Warranty.