Mishimoto has developed a direct-fit replacement thermostat for the 2002-2006 Audi A4 1.8T This Mishimoto thermostat is the ideal replacement for your failed stock thermostat. Our thermostat comes pre-installed in a durable OEM-quality housing and includes a high-quality O-ring for a perfect seal. Like all Mishimoto cooling products, this 2002-2006 Audi A4 1.8T thermostat is backed by our Mishimoto Lifetime Warranty.