The majority of modern vehicles rely on a liquid known as coolant or antifreeze to keep the Engine at optimal temperature. Coolant transfers heat away From the Motor and out of your vehicle. The Engine Coolant Thermostat balances the coolant flow between the Engine, where heat forms, and the radiator, where the heat dissipates. The Engine Coolant Thermostat in your Nissan is a petite but powerful contraption that opens and shuts depending on Engine temperature. When you first turn the key in your Nissan's ignition, the Engine Coolant Thermostat stays closed, preventing the flow of coolant till the Motor reaches optimal operating temperature. Once your Engine is sufficiently warm, the thermostat opens, allowing coolant to circulate, effectively preventing the Engine From overheating. By Supporting your vehicle's ideal temperature, a working Engine Coolant Thermostat helps prevent Engine damage and cut down on unnecessary emissions. In contrast to Motor oil and cabin air filters, coolant thermostats don't need regular replaCements. Rather, these thermostats only require replaCement if and when they malfunction. Some signs that your Engine Coolant Thermostat is broken include: Engine overheating, the Engine not coming to temperature, subpar cabin Heater performance, or an illuminated dashboard light, in certain Nissan models. Additionally, sometimes, an old Engine Coolant Thermostat may lead to erratic changes in coolant levels or faster-than-usual coolant or antifreeze deterioration. Since the signs of a faulty Engine Coolant Thermostat parallel other signs of cooling system issues, we advise having your Nissan checked out at your nearest authorized service center. However, if you're sure that the Engine Coolant Thermostat is the source of the problem, replacing it w/ an authentic OEM Engine Coolant Thermostat might help get your Engine back to its optimal operating temperature. Typically, installing a new Engine Coolant Thermostat is a job best Left to certified Nissan technicians. But if you're an excellent DIY mechanic, you may be able to do it at home. Before you start, ensure that you have the Right parts and tools for the job: a replaCement Engine Coolant Thermostat, a new Gasket or sealing compound, a socket wrench, protective gloves, a wire brush, and a bucket. Whether you decide to replace your Engine Coolant Thermostat at home or pay a visit to your closest Nissan technicians, ensure that you always look to the owner's Manual as the source of truth for all things related to your vehicle. Additionally, ensure proper fitment and reliable performance by ordering a genuine replaCement Engine Coolant Thermostat and other parts made by Nissan for your Nissan model and year. Buy this Engine Coolant Thermostat if you drive the Nissan 240SX 1989-1998, Nissan 300ZX 1990-1996, Nissan Altima 1993-2001, Nissan Axxess 1990, Nissan Frontier 1998-2004, Nissan Pathfinder 1996-2004, Nissan PICKUP 1986-1997, Nissan Sentra 1991-2002, Nissan Stanza 1990-1992, or Nissan Xterra 2000-2004. Check the What This Fits tab for more details.